Food biodiversity needs both systems, just like pandas need zoos and bamboo forests, say Marie Haga and Ann Tutwiler.
The efforts of many organisations mean that most of us understand the importance of conserving the biodiversity of wild animals and their habitats. But few of us think about food in the same way we think about pandas, even though the issues are much the same.
And as with pandas and other wild animals, conservation of agricultural biodiversity can and must be done both in the laboratory and in the field.
From pandas to seeds
If you had a choice, would you rather see a panda in a zoo, or in the bamboo forests of southern China?
For most of us, seeing wild and endangered animals in their own habitat and watching how they behave, adapt and survive in their natural surroundings would be the preferred choice. But, the role of zoos in conserving wild and endangered animals is equally important.
Many zoos are home to breeding programmes. These can help re-introduce animals into wild areas from which they have disappeared, and maintain the genetic diversity of small populations of threatened species. Zoos that are well-run carry out vital conservation research and can increase public support for conservation. And the only chance that most of us (and our kids) will have to see a panda is in a zoo.
Much in the same way, and for several decades now, dedicated researchers around the world have invested a great deal of effort in collecting and storing the seeds of different varieties of crops in genebanks, for what’s called ex situ conservation. Their collective work has created a precious global collection of over seven million seed, tissue, and other samples in many global and national genebanks.
“The problem is that systems of in situ and ex situ conservation have been largely disconnected for some time. Some conservationists even see them as antagonistic.
And while devotees of one side argue with the other, the diversity that underpins the food we eat is lost both in genebanks and in farmers’ fields.”
Marie Haga and Ann Tutwiler
At the same time, some concerns that apply to zoos — that they cannot maintain the evolutionary dynamics which allow ‘wild’ animals to evolve and adapt, for example — also apply to seed banks.
Researchers are increasingly recognising that in situ conservation is also important: maintaining crop and livestock diversity in farmers’ fields and farms, gardens, orchards, and the natural landscapes in which these are embedded.
A call for collaboration
Ex situ and in situ conservation each has their benefits.
It is relatively cheap to maintain crop diversity in a genebank, where it is safe from the vagaries of changing climates, and is readily accessible for research and breeding. But crop diversity stored in genebank is less accessible to farmers, and is not exposed to changing environments — which means it does not evolve and adapt.
On the other hand, crop diversity in farmers’ fields and under other in situ conditions, continues to evolve and adapt as a result of natural and human selections. As it evolves and adapts, this genetic diversity contributes directly to the resilience and sustainability of agricultural systems, as well as to farmers’ livelihoods and to their empowerment. But there’s a downside: it is more difficult for breeders to use in their crop improvement programmes.
This shouldn’t be about choosing one over the other — the world needs both conservation systems, with good communication channels and knowledge transfer between them. This will help to properly conserve the genepools of crops and make them available for use into the future, for food and nutritional security.
The problem is that systems of in situ and ex situ conservation have been largely disconnected for some time. Some conservationists even see them as antagonistic.
And while devotees of one side argue with the other, the diversity that underpins the food we eat is lost both in genebanks and in farmers’ fields.
Crop diversity in farmer’s fields continues to decline in many parts of the world, often driven by market forces beyond the control of farmers’ themselves. Diversity is also lost from genebanks — a shortage of funding and staff means collections are often poorly maintained.
But if we stop looking at these two forms of conservation as antagonistic but rather as complementary, attention can be focused on what matters most: how best to safeguard this diversity for the future.
The First International Agrobiodiversity Conference is an opportunity to begin anew. That’s why practitioners in all these fields, from all over the world, both industrialized and developing, and from both the formal and informal sector, are coming together in New Delhi, India this week.
This congress gives conservation and agro-biodiversity experts and policy makers the opportunity to start mapping out a future that breaks down barriers between the two approaches, integrating them to ensure global food and nutritional security.
Most importantly, this means helping politicians and the public understand that conserving the diversity of our food is just as important as conserving the diversity of wild animals.
The congress is a first step in the right direction.
Marie Haga is executive director of The Crop Trust, and Ann Tutwiler is director general of Bioversity International. Haga can be contacted on Twitter at@CropTrust, and Tutwiler at @AnnTutwiler.
Another fantastic year of discovery is over – read on for our 2016 plant science top picks!
A Zostera marina meadow in the Archipelago Sea, southwest Finland. Image credit: Christoffer Boström (Olsen et al., 2016. Nature).
The year began with the publication of the fascinating eelgrass (Zostera marina) genome by an international team of researchers. This marine monocot descended from land-dwelling ancestors, but went through a dramatic adaptation to life in the ocean, in what the lead author Professor Jeanine Olsen described as, “arguably the most extreme adaptation a terrestrial… species can undergo”.
One of the most interesting revelations was that eelgrass cannot make stomatal pores because it has completely lost the genes responsible for regulating their development. It also ditched genes involved in perceiving UV light, which does not penetrate well through its deep water habitat.
Plants are known to form new organs throughout their lifecycle, but it was not previously clear how they organized their cell development to form the right shapes. In February, researchers in Germany used an exciting new type of high-resolution fluorescence microscope to observe every individual cell in a developing lateral root, following the complex arrangement of their cell division over time.
Using this new four-dimensional cell lineage map of lateral root development in combination with computer modelling, the team revealed that, while the contribution of each cell is not pre-determined, the cells self-organize to regulate the overall development of the root in a predictable manner.
Watch the mesmerizing cell division in lateral root development in the video below, which accompanied the paper:
In March, a Spanish team of researchers revealed how the anti-wilting molecular machinery involved in preserving cell turgor assembles in response to drought. They found that a family of small proteins, the CARs, act in clusters to guide proteins to the cell membrane, in what author Dr. Pedro Luis Rodriguez described as “a kind of landing strip, acting as molecular antennas that call out to other proteins as and when necessary to orchestrate the required cellular response”.
In April, we received an amazing insight into the ‘decision-making ability’ of plants when a Swiss team discovered that plants can punish mutualist fungi that try to cheat them. In a clever experiment, the researchers provided a plant with two mutualistic partners; a ‘generous’ fungus that provides the plant with a lot of phosphates in return for carbohydrates, and a ‘meaner’ fungus that attempts to reduce the amount of phosphate it ‘pays’. They revealed that the plants can starve the meaner fungus, providing fewer carbohydrates until it pays its phosphate bill.
Author Professor Andres Wiemskenexplains: “The plant exploits the competitive situation of the two fungi in a targeted manner, triggering what is essentially a market-based process determined by cost and performance”.
The transition of ancient plants from water onto land was one of the most important events in our planet’s evolution, but required a massive change in plant biology. Suddenly plants risked drying out, so had to develop new ways to survive drought.
In May, an international team discovered a key gene in moss (Physcomitrella patens) that allows it to tolerate dehydration. This gene, ANR, was an ancient adaptation of an algal gene that allowed the early plants to respond to the drought-signaling hormone ABA. Its evolution is still a mystery, though, as author Dr. Sean Stevensonexplains: “What’s interesting is that aquatic algae can’t respond to ABA: the next challenge is to discover how this hormone signaling process arose.”
Sometimes revisiting old ideas can pay off, as a US team revealed in June. In 1930, Ernst Münch hypothesized that transport through the phloem sieve tubes in the plant vascular tissue is driven by pressure gradients, but no-one really knew how this would account for the massive pressure required to move nutrients through something as large as a tree.
Professor Michael Knoblauch and colleagues spent decades devising new methods to investigate pressures and flow within phloem without disrupting the system. He eventually developed a suite of techniques, including a picogauge with the help of his son, Jan, to measure tiny pressure differences in the plants. They found that plants can alter the shape of their phloem vessels to change the pressure within them, allowing them to transport sugars over varying distances, which provided strong support for Münch flow.
BLOG: We featured similar work (including an amazing video of the wound response in sieve tubes) by Knoblauch’s collaborator, Dr. Winfried Peters, on the blog – read it here!
Preserved remains of rope, seeds, reeds and pellets (left), and a desiccated barley grain (right) found at Yoram Cave in the Judean Desert. Credit: Uri Davidovich and Ehud Weiss.
In July, an international and highly multidisciplinary team published the genome of 6,000-year-old barley grains excavated from a cave in Israel, the oldest plant genome reconstructed to date. The grains were visually and genetically very similar to modern barley, showing that this crop was domesticated very early on in our agricultural history. With more analysis ongoing, author Dr. Verena Schünemannpredicts that “DNA-analysis of archaeological remains of prehistoric plants will provide us with novel insights into the origin, domestication and spread of crop plants”.
BLOG: We interviewed Dr. Nils Stein about this fascinating work on the blog – click here to read more!
Another exciting cereal paper was published in August, when an Australian team revealed that C4 photosynthesis occurs in wheat seeds. Like many important crops, wheat leaves perform C3 photosynthesis, which is a less efficient process, so many researchers are attempting to engineer the complex C4 photosynthesis pathway into C3 crops.
This discovery was completely unexpected, as throughout its evolution wheat has been a C3 plant. Author Professor Robert Henrysuggested: “One theory is that as [atmospheric] carbon dioxide began to decline, [wheat’s] seeds evolved a C4 pathway to capture more sunlight to convert to energy.”
Professor Stefan Jansson cooks up “Tagliatelle with CRISPRy fried vegetables”. Image credit: Stefan Jansson.
September marked an historic event. Professor Stefan Jansson cooked up the world’s first CRISPR meal, tagliatelle with CRISPRy fried vegetables (genome-edited cabbage). Jansson has paved the way for CRISPR in Europe; while the EU is yet to make a decision about how CRISPR-edited plants will be regulated, Jansson successfully convinced the Swedish Board of Agriculture to rule that plants edited in a manner that could have been achieved by traditional breeding (i.e. the deletion or minor mutation of a gene, but not the insertion of a gene from another species) cannot be treated as a GMO.
Phytochromes help plants detect day length by sensing differences in red and far-red light, but a UK-Germany research collaboration revealed that these receptors switch roles at night to become thermometers, helping plants to respond to seasonal changes in temperature.
Dr Philip Wiggeexplains: “Just as mercury rises in a thermometer, the rate at which phytochromes revert to their inactive state during the night is a direct measure of temperature. The lower the temperature, the slower phytochromes revert to inactivity, so the molecules spend more time in their active, growth-suppressing state. This is why plants are slower to grow in winter”.
A fossil ginkgo (Ginkgo biloba) leaf with its modern counterpart. Image credit: Gigascience.
In November, a Chinese team published the genome of Ginkgo biloba¸ the oldest extant tree species. Its large (10.6 Gb) genome has previously impeded our understanding of this living fossil, but researchers will now be able to investigate its ~42,000 genes to understand its interesting characteristics, such as resistance to stress and dioecious reproduction, and how it remained almost unchanged in the 270 million years it has existed.
Author Professor Yunpeng Zhaosaid, “Such a genome fills a major phylogenetic gap of land plants, and provides key genetic resources to address evolutionary questions [such as the] phylogenetic relationships of gymnosperm lineages, [and the] evolution of genome and genes in land plants”.
The year ended with another fascinating discovery from a Danish team, who used fluorescent tags and microscopy to confirm the existence of metabolons, clusters of metabolic enzymes that have never been detected in cells before. These metabolons can assemble rapidly in response to a stimulus, working as a metabolic production line to efficiently produce the required compounds. Scientists have been looking for metabolons for 40 years, and this discovery could be crucial for improving our ability to harness the production power of plants.
Genome editing technologies comprise a diverse set of molecular tools that allow the targeted modification of a DNA sequence within a genome. Unlike “traditional” breeding, genome editing does not rely on random DNA recombination; instead it allows the precise targeting of specific DNA sequences of interest. Genome editing approaches induce a double strand break (DSB) of the DNA molecule at specific sites, activating the cell’s DNA repair system. This process could be either error-prone, thus used by scientists to deactivate “undesired” genes, or error-free, enabling target DNA sequences to be “re-written” or the insertion of DNA fragments in a specific genomic position.
The most promising among the genome editing technologies, CRISPR/Cas9, was chosen as Science’s 2015 Breakthrough of the Year. Cas9 is an enzyme able to target a specific position of a genome thanks to a small RNA molecule called guide RNA (gRNA). gRNAs are easy to design and can be delivered to cells along with the gene encoding Cas9, or as a pre-assembled Cas9-gRNA protein-RNA complex. Once inside the cell, Cas9 cuts the target DNA sequence homologous to the gRNAs, producing DSBs.
The guide RNA (sgRNA) directs Cas9 to a specific region of the genome, where it induces a double-strand break in the DNA. On the left, the break is repaired by non-homologous-end joining, which can result in insertion/deletion (indel) mutations. On the right, the homologous-directed recombination pathway creates precise changes using a supplied template DNA. Credit: Ran et al. (2013). Nature Protocols.
Genome editing in crops
Together with the increased data availability on crop genomes, genome editing techniques such as CRISPR are allowing scientists to carry out ambitious research on crop plants directly, building on the knowledge obtained during decades of investigation in model plants.
The concept of CRISPR was first tested in crops by generating cultivars that are resistant to herbicides, as this is an easy trait to screen for and identify. One of the first genome-edited crops, a herbicide-resistant oilseed rape produced by Cibus, has already been grown and harvested in the USA in 2015.
Researchers used CRISPR to engineer a wheat variety resistant to powdery mildew (shown here), a major disease of this crop. Image credit: NY State IPM Program. Used under license: CC BY 2.0.
Genome editing could also revolutionize the management of viral plant disease. The CRISPR/Cas9 system was originally discovered in bacteria, where it provided them with molecular immunity against viruses, but it can also be moved into plants. Scientists can transform plants to produce the Cas9 and gRNAs that target viral DNA, reducing virus accumulation; alternatively, they can suppress those plant genes that are hijacked by the virus to mediate its own diffusion in the plants. Since most plants are defenseless against viruses and there are no chemical controls available for plant viruses, the main method to stop the spread of these diseases is still the destruction of the infected plant. For the first time in history, scientists have an effective weapon to fight back against plant viruses.
The cassava brown streak disease virus can destroy cassava crops, threatening the food security of the 300 million people who rely on this crop in Africa. Image credit: Katie Tomlinson (for more on this topic, read her blog here).
Genome editing will be particularly useful in the genetic improvement of many crops that are propagated mainly by vegetative reproduction, and so very difficult to improve by traditional breeding methods involving crossing (e.g. cassava, banana, grape, potato). For example, using TALENs, scientists from Cellectisedited a potato line to minimize the accumulation of reducing sugars that may be converted into acrylamide (a possible carcinogen) during cooking.
Concerns about off-targets
One of the hypothesized risks of using CRISPR/Cas9 is the potential targeting of undesired DNA regions, called off-targets. It is possible to limit the potential for off-targets by designing very specific gRNAs, and all of the work published so far either did not detect any off-targets or, if detected, they occurred at a very low frequency. The number of off-target mutations produced by CRISPR/Cas9 is therefore minimal, especially if compared with the widely accepted random mutagenesis of crops used in plant breeding since the 1950s.
GM or not-GM
Genome editing is interesting from a regulatory point of view too. After obtaining the desired heritable mutation using CRISPR/Cas9, it is possible to remove the CRISPR/Cas9 integrated vectors from the genome using simple genetic segregation, leaving no trace of the genome modification other than the mutation itself. This means that some countries (including the USA, Canada, and Argentina) consider the products of genome editing on a case-by-case basis, ruling that a crop is non-GM when it contains gene combinations that could have been obtained through crossing or random mutation. Many other countries are yet to issue an official statement on CRISPR, however.
Recently, scientists showed that is possible to edit the genome of plants without adding any foreign DNA and without the need for bacteria- or virus-mediated plant transformation. Instead, a pre-assembled Cas9-gRNA ribonucleoprotein (RNP) is delivered to plant cells in vitro, which can edit the desired region of the genome before being rapidly degraded by the plant endogenous proteases and nucleases. This non-GM approach can also reduce the potential of off-target editing, because of the minimal time that the RNP is present inside the cell before being degraded. RNP-based genome editing has been already applied to tobacco plants, rice, and lettuce, as well as very recently to maize.
In conclusion, genome editing techniques, and CRISPR/Cas9 in particular, offers scientists and plant breeders a flexible and relatively easy approach to accelerate breeding practices in a wide variety of crop species, providing another tool that we can use to improve food security in the future.
For more on CRISPR, check out this recent TED Talk from Ellen Jorgensen:
About the author
Dr Damiano Martignago is a plant molecular biologist who graduated from Padua University, Italy, with a degree in Food Biotechnology in 2009. He obtained his PhD in Biology at Roma Tre University in 2014. His experience with CRISPR/Cas9 began in the lab of Prof. Fabio Fornara (University of Milan), where he used CRISPR/Cas9 to target photoperiod genes of interest in rice and generate mutants that were not previously available. He recently moved to Rothamsted Research, UK, where he works as Genome Editing Specialist, transferring CRISPR/Cas9 technology to hexaploid bread wheat with the aim of improving the efficiency of genome editing in this crop. He is actively involved with AIRIcerca (International Association of Italian Scientists), disseminating and promoting scientific news.
Aquaporins are water-channel proteins that move water molecules through cell membranes. They are found in every kingdom of life. Cell membranes are semi-permeable to water, but often require more rapid movements of water across membranes; cells achieve this using aquaporins.
Aquaporins play key roles in your kidneys, which typically filter each of the three liters of plasma in your body 60 times per day – that’s 180 liters of plasma each day! Around three times your body weight in water passes through your own aquaporins each day.
Around 50% of global rainfall passes through plants, and half of this moves through the aquaporins. Image credit: Dennis Seiffert. Used under license: CC BY-ND 2.0.
Have you got on the scales recently? Nearly 70% of your body weight is water. Water is the major component of cells in all of your tissues and this is the same for plants. Around 50% of global precipitation passes through plants, and half of this moves through aquaporins, so aquaporins account for the largest movement of mass for any protein on earth.
Often, in cell membranes, four aquaporin proteins will come together to form a tetramer to assist with the transportation of water across the cell membrane. There are types of aquaporins that only transport water, and others that transport glycerol, neutral acids or gasses. Historically, plant science literature has reported that the molecular structure of aquaporins prevents any charged particles, such as ions, from permeating. This is different in the animal world where there are reports of aquaporins that are permeable to ions. For example, in humans one of the most highly expressed aquaporins, AQP1, can function as a dual water and ion channel.
Testing plant aquaporins in frog cells
Recently, we observed that one of the most highly expressed plant aquaporins is permeable to ions when expressed in heterologous systems such as Xenopus laevis (frog) oocyte (egg) cells or yeast cells. This indicates that plants may also have types of aquaporins that can function as a dual water:ion channels.
The function of plant aquaporins can be studied by expressing them in different systems such as the Xenopus laevis oocyte cells pictured here. Photo credit: Dr Caitlin Byrt.
If you want to know if a particular plant aquaporin can function as a water channel you can test it by expressing the aquaporin in a laboratory oocyte expression system. We use a tiny needle to inject RNA coding for plant aquaporins of interest into the oocyte, and for control oocytes we inject the same amount of water. The oocytes are kept in a saline solution and we usually study them one or two days after injecting the RNA to allow time for them to synthesize the protein.
If you place oocytes expressing an aquaporin into water alongside control oocytes, then the aquaporin-expressing oocytes will burst much quicker than the controls because water rushes in through the aquaporin and causes the cell to swell rapidly. To explore whether a protein conducts ions, we use electrodes to measure the currents generated when charged ions pass across the oocyte membrane. We can also use ion-specific electrodes to explore which ions are transported.
AtPIP2;1 can transport water and ions
The plant aquaporin we studied is coded in the genome of the model plant Arabidopsis; it is a plasma membrane-located protein called AtPIP2;1. The AtPIP2;1 protein is known to be highly prevalent in root epidermal cell membranes, and it also functions in the guard cells of leaves, which act like tiny valves to regulate the uptake of carbon dioxide for photosynthesis and the release of water vapor.
The model plant Arabidopsis has an aquaporin, AtPIP2;1, that can function as a dual water:ion channel. Photo credit: Dr. Jiaen Qiu.
We observed that AtPIP2;1 expression induces both water and ion (salt) movement across the cell membrane of oocytes. We know that the ionic conductance can be carried in part by sodium ions and that it is inhibited by calcium, cadmium and protons. This means AtPIP2;1 is a candidate for a previously reported calcium-sensitive non-selective cation channel responsible for sodium ion entry into Arabidopsis roots in saline conditions.
We are investigating the physiological role of ion permeable aquaporins in plants, and exploring how plants regulate the coupling of ion and water flow across key membranes. The regulation of ion permeability through plant aquaporins could be important in the control of water flow and regulation of cell volume. There is increasing discussion around the hypothesis that plants could drive water transport in the absence of water potential differences using salt and water co-transport, and this makes us wonder whether ion-permeable aquaporins may be involved. Testing whether ion-permeable aquaporins can function as an ‘all-in-one’ osmotic system in plants is an exciting new direction for research in this field.
Dr. Caitlin Byrt, Professor Steve Tyerman and colleagues are investigating whether aquaporins permeable to ions are present in a range of different plant species. Photo credit: Wendy Sullivan
Dr. Mike Roberts, Lancaster University, UK, Mike with an experiment to test the effects of parental herbivory on defense priming in the next generation of Arabidopsis plants. (Photo credit: Lancaster University)
It is widely accepted that achieving agricultural sustainability means reducing our reliance on synthetic agrochemicals. One major group of agrochemicals is pesticides, which include the insecticides and fungicides that protect crop plants against pests and diseases. Pests and diseases aren’t going to go away, so reducing pesticide usage means that alternative crop protection approaches are needed. EU Directive 2009/128/EC (Sustainable Use of Pesticides) recommends the use of integrated pest and disease management (IPM) – the combined use of multiple approaches that together provide sufficient protection.
Our contribution to this challenge has been to identify ways in which we might enhance a plant’s own natural defense mechanisms. Plants have a wide array of structural and chemical defenses that they can employ to fight off enemies. Many of these are inducible, meaning that they are only activated in response to attack, which allows plants to balance the costs and benefits of defense. For crop plants, these costs can often translate into reduced yields. Spraying with compounds that switch on inducible defenses, such as the plant hormones jasmonic acid (JA) and salicylic acid (SA), can make plants more resistant, but this approach also risks unwanted growth reductions.
Fortunately, evolution has produced another way of regulating inducible defenses that we can take advantage of: the phenomenon we refer to as ‘priming’. When we ourselves get infected with something like a virus, our immune system generates antibodies to quickly fight it off, but it also produces memory cells that can respond to the same infection many months, or even years, in the future, with a more rapid and effective immune response. This is the basis of the familiar concept of vaccination. While plants don’t make antibodies, they are nevertheless able to alter future patterns of defense activation in response to previous infection by disease or feeding by herbivorous insects; thus, priming results in a faster and stronger activation of future inducible defense responses.
Transgenerational immune priming enhances disease resistance in Arabidopsis. All the plants in the photograph were inoculated by spraying the whole tray with a suspension of Pseudomonas syringae bacteria. The plants on the right side of the photo are from seed collected from parent plants that were infected with the same P. syringae bacteria, whilst those on the left come from healthy parents. (Photo credit: Belinda Ameyaw)
If we can find ways to prime defenses in crop plants, we might be able to improve pest and disease resistance with minimal impacts on yield. One way to do this is through seed treatments. We found that treating seeds with the defense hormone JA provides long-term enhanced resistance against herbivory and some fungal diseases, without affecting growth and development. We were able to patent this discovery, and the approach has since been successfully commercialized. The same approach can also be used to prime defenses against other forms of biotic and abiotic stress.
How and why seed treatments provide long-term defense priming can be explained by the phenomenon of transgenerational immune priming, which my lab has also been investigating. After our success with the seed treatment, we wondered, “What if seeds were exposed to hormones like JA during the course of their development on the parent plant?” We tested this by infecting plants with bacteria or exposing them to herbivores, and then examined defense in their offspring. Remarkably, we saw that priming responses established in the parent were passed on to the offspring; something we refer to as transgenerational immune priming.
The evidence we have at present suggests that the mechanism for this heritable stress memory is epigenetic, meaning the genes that control priming are chemically tagged to alter their activity. These epigenetic modifications don’t involve changes in the DNA sequence and are reversible, allowing rapid, flexible responses to environmental stress. Understanding the nature of these epigenetic changes may provide another way to exploit priming for crop protection. Introducing the right epigenetic marks onto genes in elite crop varieties may enable the priming of defense without altering their genetic make-up. Given the difficulty of introducing new chemical and biological methods of crop protection, which require time-consuming and costly regulatory approval before they can be brought to market, this could prove an especially attractive option in the future.
Plant samples in the genebank at the International Center for Tropical Agriculture’s Genetic Resources Unit, at the institution’s headquarters in Colombia. Credit: Neil Palmer / CIAT. Used under license: CC BY-SA 2.0.
It was too dry in the Australian region of Wimmera to produce crops last summer. This year, floods are set to wipe out yields again. Like a number of other regions across the planet, climate change is starting to be felt.
For Norton and many of her colleagues in agricultural genetics, the picture is increasingly clear: The variety of crops used today are not able to withstand the changing conditions and changes expected in the future.
Australia’s biodiversity may offer some help, according to discussions at the recent International Genebank Managers Annual General Meeting held in Horsham, Victoria. The gathering, which brings together 11 countries, focused on how to better conserve seeds, build databases to manage collections, boost capacity across the world and fill gaps in genebanks.
Researchers are particularly interested in crop wilds, “the ancestors of our domesticated crops,” Marie Haga, executive director of the The Crop Trust, explained to Devex. Australia is one of the richest sources of these seeds. “It’s like the wolf being the ancestor to our domesticated dogs. Crop wild relatives have traits that we have lost in the domestication process — they might need less water, might live in unfriendly conditions, may be resistant to pests and diseases.”
As climate change continues to batter agricultural yields, crop wild relatives could provide resilience. The seeds give breeders and farmers new options of plant varieties with traits to withstand a variety of conditions based on the harsh climates they are found — drought, fire, flood, poor soil, high salinity.
For Haga, crop wild relatives are a solution for food security. “The challenge is that many of the varieties widely used in modern agriculture are very vulnerable, because we have been breeding on the same line and they are adapted to very specific environment,” Haga said. Varieties that flourish today, she said, could wither as the climate fluctuates.
“Utilization of the natural diversity of crops is key to the future,” she said. “The climate is rapidly changing and we need to feed a growing population with more nutritious food. It is very hard to see how we can do this unless we go back to the building blocks of agriculture.”
Norton agreed: “Crop wild relatives have an amazing adaptability to changing conditions,” she told Devex. “When we talk about food security, we are talking about getting varieties in farm paddocks that have greater resilience to extreme conditions. It may not be the highest yield, but you are going to get something from this crop.”
Why have they been overlooked?
Crop wild relatives have so far been underutilized in the research and breeding process of crops.
“We have this fabulous natural diversity out there including 125,000 varieties of wheat and 200,000 varieties of rice.” Haga said. “We have not at all unlocked the potential of these crops.”
One reason is a dearth of research. “Adapting Agriculture to Climate Change: Collecting, Protecting and Preparing Crop Wild Relatives,” a 10-year project led by Haga to ensure long-term conservation of crop wild relatives, conducted a global survey of distribution and conservation and found that of 1,076 known wild relatives for 81 crops, more than 95 percent are insufficiently represented in genebanks and 29 percent are completely missing. They are missing purely due to the fact that they have yet to be collected.
“Genebank managers are generally open to include crop wild relatives in their collections.” Haga said. “It’s just quite simply that not enough work has been done in this area and the full potential is yet to be realized,” she said.
At the moment, seeds are being collected in 25 countries around the world as part of the crop wild relative project, but it is Australia that has been identified as one of the richest sources for crop wild relatives in the world. Because of the continent’s low population density and vast, undisturbed natural environment, a wide variety of species have been conserved, said Norton.
Australia holds significant diversity of wild relatives of rice, sorghum, pigeon pea, banana, sweet potato and eggplant currently missing from global collections, according to research by the Australian Seed Bank Partnership. Forty species have been prioritized for collection with high hopes that they will enable crops to withstand the harsh environmental conditions in which Australian species are found.
There are still many areas of Australia yet to be surveyed, and the full extent of its agricultural riches may yet to be tapped.
Australian researchers will play an important role in pre-breeding local species of wild relatives to improve their use in breeding programs. Crop wild relatives have historically been used in a variety of crops including synthetic wheat, but Australian native wild relatives have been harder to include in the breeding process.
“In the next 10 to 15 years it would be surprising if there is not something coming out that hasn’t got a component of Australian native wild relative in it,” Norton said who is currently involved in the collection of Australian crop wild relatives.
Collection of crop wild relatives is time sensitive
There is an urgency to collect crop wild relatives. Not only are wild species needed now to support changing environmental conditions affecting crops and farming, urbanization is putting crop wild relatives at risk of disappearing.
“We need to collect these sooner rather than later,” Norton told Devex. “Urbanization has a big impact on any native environment, let alone crop wild relatives. We know what species on our target list are more threatened than others — urbanization, flooding and fire are all risks to their security. We certainly have a priority list of species to collect and we need to make sure we target the ones that are under threat first.”
Once the varieties are conserved, breeders and farmers will need to be convinced to start using crop wild relatives. Many are already on board. “Most breeders understand these wild relatives have great potential,” Haga said.
Still, wild relatives can be difficult to work with and produce a lower yield. Haga expects there to be some reluctance, though limited.
“The understanding of the need is increasing and we feel very confident that this material will be used and some of them may be the game changer we are looking for,” she said.
The plans for crop wild relatives
Haga’s 10-year project on crop wild relatives is halfway complete. They are nearing the end of the collection phase and entering the pre-breeding process, before they are able to breed and deliver new species to farmers.
Australian support for the program includes an agreement for additional amount of $5 million. That comes on top of previous support of $21.2 million to the Crop Diversity Endowment Fund, which supports crop diversity globally and with a focus on the Indo-Pacific. Brazil, Chile, Germany, Japan, New Zealand, Norway, Switzerland and the United States are among other supporters of the endowment fund that hopes to reach $850 million. In Australia, further resources are still required to fund and support better seed collection at home.
Globally, plans for crop wild relatives includes raising greater awareness of their potential and importance.
“We have a big job to do to create awareness of the important of crop diversity generally and crop wild relatives specifically,” Haga said. “We have been speaking for years about biodiversity in birds and fish and a range of other animals, but we have talked very little about conserving the diversity of crops. I will fight for all types of diversity, but especially plants.”
Agricultural production in temperate regions is highly productive with a significant proportion of global output originating from temperate (i.e. non-tropical) countries – 21% of global meat production and 20% of global cereal production [link opens PDF] originate from Europe alone. This proportion is very likely to increase in light of climate change.
Little fluffy clouds: temperate zones are well suited to agricultural production. Image credit: connect11/Thinkstock
TempAg is an international research collaboration network that was established to increase the impact of agricultural research and inform policy making in the world’s temperate regions. Its work does not solely focus on research, but also provides insights into current thinking through mapping existing scientific findings and outstanding knowledge gaps. In this way, the network aspires to become a platform for the alignment of national agricultural research and food partnership programs (such as Global Food Security) that will enable the development of more effective agricultural policies with a long-term vision.
Since its official inauguration in Paris in April 2015, TempAg has been leading a series of on-going workstreams around:
Boosting resilience of agricultural production systems at multiple scales and levels
Optimising land management for ecosystem services and food production
Improving sustainability of food productivity in the farms & enterprise level
After 18 months of existence, TempAg held a foresight workshop in London on 5–7 October to determine its future priorities.
Forty delegates took part in the workshop, coming from the 14 different countries in the temperate region, and from academia, policy, industry, and professionals at the science–policy interface. Through a series of presentations and interactive sessions, participants were invited to consider what the current and future challenges are in temperate agriculture, taking into account the needs of policy makers and industry in helping them to improve sustainable agriculture practices.
To tackle sustainability in temperate agriculture, there is a need to better manage risks and stresses (both biotic and abiotic), as well as finding ways to manage the restoration of natural capital, ecosystem services, and soils. During the workshop, it was noted that utilizing the diversity within different agricultural systems, via identifying the best practice and using the appropriate technological mix, may be a way forward in making production systems more sustainable.
Participants stressed the importance of taking a holistic view of the sustainability agenda within agriculture, without just focusing on environmental aspects. This means also taking into consideration socioeconomic factors, such as making food value chains (like turning milk into cheese), more equitable by identifying who gets the equity from the food commodities’ prices, or identifying what the optimum legal framework for sharing data might be.
The group also considered sustainable agriculture issues from a policy and industry needs angle. It was interesting to see that dealing with shocks (environmental, socioeconomic, and technological) featured highly in this discussion as well. It was suggested that increasing resilience to these shocks could be facilitated via the widespread diffusion of existing technologies. Engaging with farmers during this time would be necessary to identify technology uptake barriers.
Future-proofing agricultural resilience and enhancing the capacity to respond to shocks was deemed an urgent priority, so the development of a comprehensive map identifying the multiple shocks that could impact on farm resilience in temperate zones might be a future workstream for TempAg. Work in this area could help develop models to assess the flexibility within agricultural production systems.
What we eat is largely based on the types of food we produce. Therefore, healthy diets are intrinsically linked with our production systems. Another area of interest for TempAg could be to explore what the nutritional value of crops should be for better health, and what a nutritional diet will look like for sustainable temperate agriculture. Developing frameworks in this area could further inform future farming practices in temperate areas.
Since TempAg’s initiation, two major global policy agendas have been adopted by the international community: the Sustainable Development Goals and the Paris COP21 agreement. Identifying what types of data and scientific evidence policy makers will need to achieve the agriculture-relevant targets was another area where TempAg could focus its activity moving forward.
Finally, delegates highlighted areas of work that could help to build more effective policies with a longer-term vision. These included developing economic tools for valuing natural capital and ecosystem services, as well as integrated assessment tools to monitor the performance and impact (environmental cost) of existing policies.
Evangelia is International Coordinator & Programme Manager for the Global Food Security program (GFS). Before joining GFS, Evangelia worked as an Innovation Manager for GFS partners BBSRC. She holds a PhD in plant development and genetics from the University of Oxford.
As popular British botanist (and GPC blog guest) James Wong wrote in the UK’s Guardian newspaper earlier this year: “gardening is good for you”. Ask most people how they can benefit from gardening, and they might suggest improved physical activity or stress relief, but this is only scratching the surface.
The People Plant Council (PPC) is an international group of researchers and other industrial and not-for-profit partners, which aims to understand the effects plants have on our well-being. By communicating its findings to affiliates and the public, the PPC encourages the translation of these findings into health-enhancing programs. The PPC was established after a 1990 symposium entitled, “The Role of Horticulture in Human Well-Being and Social Development”, which identified a need for scientific research into the influence of horticulture on human health and quality of life.
The benefits of plants
The earliest reports of horticulture being used to improve human health come from ancient Egypt, where members of royalty were prescribed walks through the palace gardens as a treatment for mental illness (1). Today, research from the PPC and others has identified wide-ranging psychological, physiological, and sociological benefits from plants.
Gardening is good for both physical and mental health. Credit: Shyn Darkly. Used under license: CC BY 2.0.
The physiological benefits of gardening include an increase in physical activity (and the resulting improvements in cardiovascular fitness, muscle strength and aerobic capacity), but there are also some less obvious benefits, including better hand-eye coordination, balance, and an improvement in some chronic diseases. In one PPC-led study, elderly women took part in 50-minute gardening sessions twice a week, which led to significant improvements in their dexterity, muscle mass and cognitive ability compared to a control group (2).
There are also significant psychophysiological benefits to horticulture. Two interesting studies found that exposure to soil – or more precisely, to a common bacterium in soil (Mycobacterium vaccae) – improved the quality of life for both human cancer patients and mice by inducing the production of the brain’s “happy chemical”, seratonin (3,4). Contact with nature has also been shown to improve memory, concentration and stress.
People connect with each other around plants; whether it’s admiring a friend’s garden, giving a partner some flowers, or sharing a picnic at the local park, most of us have experienced the sociological benefits of plants. A PPC-led study found that horticulture was brilliant for improving peer relationships in schools too; a collaborative gardening program for small groups of 12–13 year-olds led to meaningful friendships that persisted after the class ended. The gardening students were also more law-abiding and social than the control group.
People bond over the experience of enjoying nature together. Credit: Amelia Wells. Used under license: CC BY 2.0.
At the IPPS meetings, delegates address the inherent impacts of nature on every aspect of our lives, including physical and mental health, and education. Dr Park elaborated, “The IPPS is attended by researchers, practitioners (such as horticultural therapists), and educators in various fields such as horticultural science, ethnobotany, psychology, nursing, occupational therapy, etc. The International Society for Horticultural Science supports the PPC, and enables us to publish the IPPS proceedings in their journal, Acta Horticulturae”.
This week we spoke to Professor Neil Bruce, whose research at the University of York (UK) focuses on metabolic pathways. His insights into the detoxification of pollutants by plants and microorganisms has led to promising new solutions to help clean up polluting explosives from military testing.
Could you begin by telling us a little about your research interests?
I have very broad research interests that often revolve around finding enzymes for biotechnological applications. A particular focus of my lab is the biochemistry and molecular genetics of plant and microbial metabolism of xenobiotic (foreign) compounds, such as environmental pollutants. Elucidating these metabolic pathways often results in the discovery of new enzymes that catalyze interesting chemistries. Being a biologist at heart, I’m interested in the evolutionary origin of these enzymes, but also by studying their structure and function I’m exploring how these enzymes can be engineered to further improve their properties for a particular application, such as environmental remediation or biocatalysis.
You spoke at the GARNet 2016 meeting about engineering plants to remediate explosives pollution. Could you explain what this problem is and how it affects both people and the environment?
Explosive compounds used in munitions are highly toxic and the potential for progressive accumulation of such compounds in soil, plants, and groundwater is a significant concern at military sites. It is estimated that in the US alone, 10 million hectares of military land is contaminated with components of munitions. The explosives mainly used in artillery, mortars and bombs are 2,4,6-trinitrotoluene (TNT) and Composition B (containing TNT and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX)). The US Department of Defense estimated that the clean-up of unexploded ordnance, discarded military munitions and munition constituents on its active ranges would cost between $16 billion and $165 billion. Explosives pollution is, however, a global problem, with large amounts of land and groundwater contaminated by TNT and RDX, including polluted sites in the UK that date back to the First and Second World Wars. Explosives pollution will continue to be a pressing issue while there is a requirement for military to train and the existence of armed conflict requires munitions to be manufactured. There is an urgent need to develop sustainable in situ technologies to contain and treat these pollutants.
TNT is toxic to plants because of the actions of an enzyme called monodehydroascorbate reductase, which breaks TNT down into a toxic form. Plants lacking this enzyme, such as the mdhar6 mutant plants on the right, can grow very well on TNT-polluted soil. Credit: Johnston et al. (2015).
How did you develop the idea of using plants to remove explosives pollution? What benefits do plants have over the microorganisms from which the enzymes are obtained?
We have worked closely with the UK Ministry of Defence and US Army to understand the fate of explosives in the environment. Knowledge of their effects on biological systems is important, as this information can be used to support the management of contaminated sites. We have, therefore, been uncovering the molecular mechanisms behind these detoxification processes in plants, and have used this knowledge, in combination with studies on the bacterial degradation of pollutants, to successfully engineer transgenic plants able to remediate toxic explosive pollutants in a process called ‘phytoremediation’.
An innovative aspect of our work has been the use of genetic engineering to combine the biodegradative capabilities of explosives-degrading bacteria with the high biomass, stability and detoxification systems inherent in plants. While it is possible to find explosives-degrading bacteria on polluted land, they do not degrade the explosives fast enough to prevent leaching into the groundwater. Our engineered transgenic plant systems, however, can efficiently remove toxic levels of TNT and RDX from contaminated soil and water.
You mentioned that you are currently testing transgenic switchgrass to remove RDX and TNT pollution in the US. Why did you choose this species and have you considered developing other species suited to different environments?
Plants appropriate for the phytoremediation of explosives need to be adaptable to conditions on military ranges, for example, they need good fire tolerance, and to be able to grow over a wide geographical range. Switchgrass meets these criteria, and is also deep-rooting, can be grown on marginal lands, and researchers can benefit from established methods for genetically engineering switchgrass. We have also been engineering other grass species and have considered fast-growing deep-rooting trees such as poplar.
In a poetic twist, rather than turning fertilizers into explosives, Professor Bruce’s phytoremediating plants convert explosives into fertilizer. Credit: Neil Bruce.
How quickly can engineered plants remove this pollution?
In the lab these plants can remove levels of explosives pollution found in the environment within a matter of days. We are currently carrying out field trials with our transgenic plants on a military site in the US, to observe their phytoremediation effectiveness in the real world. If these trials are successful, a number of demonstration studies on contaminated sites will be required to convince end users of the benefits of phytoremediation for remediating and maintaining military land. These demonstration studies will also allow us to evaluate any risks, which will be important to obtain further approval from the US Department of Agriculture to be able to use these plants on a larger scale.
What other projects are you working on? Could you elaborate on any recent discoveries?
As well as explosives, we are also working on the use of plants to extract platinum group metals (PGMs) from mining waste. PGMs are used in an ever-expanding array of technologies and demand is spiralling upwards; however, these are rare and expensive to mine. It is essential that these metal reserves are utilized and recycled responsibly, not dispersed and lost into the environment. Plants can take up metals from their environment and, in the case of PGMs, can deposit them as nanoparticles within their tissues. Importantly, we have recently shown that plants containing palladium nanoparticles can also be used to make efficient biocatalysts, and we are currently using synthetic biology in plants to improve palladium uptake and nanoparticle formation.
Could you give a brief introduction to Farming Futures and its mission?
Farming Futures is an independent, UK-based, inclusive agri-food supply chains alliance. Our mission is to work with researchers and industry to share knowledge, with the aim of improving the sustainability and productive efficiency of agriculture, all within the context of healthy, high-quality food.
The inauguration meeting of Farming Futures in 2009, then known as the Centre of Excellence for UK Farming. Left-Right: Tim Williams, Wayne Powell, Heather Jenkins, David Davies, Philip Morgan, Jamie Newbold.
How has plant and crop research been integrated into the recommendations presented by Farming Futures?
Plant science is the fundamental driver for agri-food development. We work closely with industry, as well as the AHDB and other farm advisory bodies across the UK to inform them about new developments. Accelerated, directed breeding programs using genomic and phenomic technologies are helping us to develop new varieties that offer more productive, more resilient, environmentally friendly plants – not just as food crops, but also for soil quality, nutrient retention, flood reduction, energy biomass, renewable chemistry, and a host of other desirable characteristics.
Historically, to paraphrase a fellow botanist, we have bred ‘needy, greedy plants’ that deplete resources and need lots of nasty chemicals to keep them growing. Now scientists are mining the genomes of crop ancestors to rediscover the genetic traits we unwittingly threw away on the route to increased yield.
What roles do research partners such as universities play?
We work together in a pre-competitive way to enable research, and to represent farming within agri-food policy – researchers from different organizations can collaborate thanks to our partners’ trusting relationships with each other. Collaborations in science are vital because the problems our global society faces are multi-factorial, non-linear and multi-disciplinary. They are far too complex for the typical university research team, working alone, to address efficiently. We need the equivalent of the CERN Large Hadron Collider project for agri-food.
In addition to helping researchers to bring in millions of pounds worth of applied research projects (at least £12 million, but it is notoriously difficult to find out what industry is funding), Farming Futures helped to establish the government-funded Agri-Food Tech Centres of Innovation for a total of around £90 million, bringing in industry to co-fund and support three of the four: the Agrimetrics Centre, Agri-Epi-Centre and Centre of Innovation Excellence in Livestock. In time, these Centres will catalyze a lot of collaborative research and will help stimulate innovation and technology uptake by industry.
…Economic returns on R&D are about 27 X investment but takes an average of 23 yrs for R&D innovation to be taken up by agriculture. 2/2
What climate change challenges will farmers face? Are there any specific challenges that Farming Futures can address?
Farming Futures and its network brings together scientists from different disciplines to discuss these problems and potential solutions. For instance, people from the UK’s national weather service (the Met Office) and some of the biggest food retailers and processors in the world come together at our conferences and workshops to think through scenarios and solutions. These solutions include breeding crops for increased resilience, not just peak yield. We are running out of fungicides that work efficiently, in the same way that we are running out of antibiotics; however, some very clever scientists have worked out some potential solutions that are more environmentally sound, so I am an optimist.
This problem solving is best done at the supply-chain level as it brings in a wider expertise. As I repeat often, a colleague once said to the board of one of the world’s biggest brewers, “No barley = no beer = no business”, inferring the question, “What are you doing to ensure that barley growers are going to be able to supply you in the future?”
Your website has an interesting study from 2011 highlighting six potential jobs of the future, including geoengineer, energy farming, web 3.0 farm host, pharmer, etc. How can students direct their skill development to meet the needs of the future?
There are many emerging jobs and skills, but each of these named jobs from 2011 are actually in practice now. The web 3.0 has now become web 4.0, which is the “internet of things”, with data collection from lots of devices including drones for precision agriculture and robots for weeding and picking crops.
The future of agri-food is in big data, including consumer behavior, weather forecasting, genomics, phenomics, and real-time analysis of the growth progress of plants and animals on-farm. We need more electronic and mechanical engineers with an understanding of biology, as well as more biologists who work within the agri-food industries and in government policy development.
The Farming Futures exhibition stand at the Livestock Event, NEC Birmingham, 2012.
What are you currently working on?
We are currently working with partners on a number of projects across the Agri-Food Tech Centres and trying to form more research collaborations. One of our big projects is The National Library for Agri-Food. I am currently working with web developers and experts from Jisc and the British Library to scope the requirements and to build a demonstration web site.
Finally, I would just like to add that we are open to collaborations across agri-food supply chains and will work to foster them, either openly or privately as appropriate.