Striga hermonthica – a beautiful but devastating plant…

This week’s post was written by Caroline Wood, a PhD candidate at the University of Sheffield.

When it comes to crop diseases, insects, viruses, and fungi may get the media limelight but in certain regions it is actually other plants which are a farmer’s greatest enemy. In sub-Saharan Africa, one weed in particular – Striga hermonthica – is an almost unstoppable scourge and one of the main limiting factors for food security.

Striga is a parasitic plant; it attaches to and feeds off a host plant. For most of us, parasitic plants are simply harmless curiosities. Over 4,000 plants are known to have adopted a parasitic mode of life, including the seasonal favorite mistletoe (a stem parasite of conifers) and Rafflesia arnoldii, nicknamed the “corpse flower” for its huge, smelly blooms. Although the latter produces the world’s largest flower, it has no true roots – only thread-like structures that infect tropical vines.

When parasitic plants infect food crops, they can turn very nasty indeed. Striga hermonthica is particularly notorious because it infects almost every cereal crop, including rice, maize, and sorghum. Striga is a hemiparasite, meaning that it mainly withdraws water from the host (parasitic plants can also be holoparasites, which withdraw both water and carbon sugars from the host). However, Striga also causes a severe stunting effect on the host crop (see Figure 1), reducing their  yield to practically nothing. Little wonder then, that the common name for Striga is ‘witchweed’.

Striga-infected sorghum

Figure 1: Striga-infected sorghum. Note the withered, shrunken appearance of the infected plants. Image credit: Joel Ransom.

 

Several features of the Striga lifecycle make it especially difficult to control. The seeds can remain dormant for decades and only germinate in response to signals produced by the host root (called strigolactones) (Figure 2). Once farmland becomes infested with Striga seed, it becomes virtually useless for crop production. Germination and attachment takes place underground, so the farmer can’t tell if the land is infected until the parasite sends up shoots (with ironically beautiful purple flowers). Some chemical treatments can be effective but these remain too expensive for the subsistence farmers who are mostly affected by the weed. Many resort to simply pulling the shoots out as they appear; a time-consuming and labor-intensive process. It is estimated that Striga spp. cause crop losses of around US $10 billion each year [1].

Certain crop cultivars and their wild relatives show natural resistance to Striga. Here at the University of Sheffield, our lab group (headed by Professor Julie Scholes) is working to identify resistance genes in rice and maize, with the eventual aim of breeding these into high-yielding cultivars. To do this, we grow the host plants in rhizotrons (root observation chambers) which allow us to observe the process of Striga attachment and infection (see Figure 3). Already this has been successful in identifying rice cultivars that have broad-spectrum resistance to Striga, and which are now being used by farmers across Africa.

 

Life cycle of Striga

Figure 2: Life cycle of Striga spp. A single plant produces up to 100,000 seeds, which can remain viable in the soil for 20 years. Following a warm, moist conditioning phase, parasite seeds become responsive to chemical cues produced by the roots of suitable hosts, which cause them to germinate and attach to the host root. The parasite then develops a haustorium: an absorptive organ which penetrates the root and connects to the xylem vessels in the host’s vascular system. This fuels the development of the Striga shoots, which eventually emerge above ground and flower. Figure from [2].

 

But many fundamental aspects of the infection process remain almost a complete mystery, particularly how the parasite overcomes the host’s intrinsic defense systems. It is possible that Striga deliberately triggers certain host signaling pathways; a strategy used by other root pathogens such as the fungus Fusarium oxysporum. This is the focus of my project: to identify the key defense pathways that determine the level of host resistance to Striga. It would be very difficult to investigate this in crop plants, which typically have incredibly large genomes, so my model organism is Arabidopsis thaliana, the workhorse of the plant science world, whose genome has been fully sequenced and mapped. Arabidopsis cannot be infected by Striga hermonthica but it is susceptible to the related species, Striga gesnerioides, which normally infects cowpea.  I am currently working through a range of different Arabidopsis mutants, each affected in a certain defense pathway, to test whether these have an altered resistance to the parasite.  Once I have an idea of which plant defense hormones may be involved (such as salicylic acid or jasmonic acid), I plant to test the expression of candidate genes to decipher what is happening at the molecular level.

Striga-infected Arabidopsis

Figure 3: One of my Arabidopsis plants growing in a rhizotron. Preconditioned Striga seeds were applied to the roots three weeks ago with a paintbrush. Those that successfully attached and infected the host have now developed into haustoria. The number of haustoria indicates the level of resistance in the host. Image credit: Caroline Wood.

 

It’s early days yet, but I am excited by the prospect of shedding light on how these devastating weeds are so effective in breaking into their hosts. Ultimately this could lead to new ways of ‘priming’ host plants so that they are armed and ready when Striga attacks. It’s an ambitious challenge, and one that will certainly keep me going for the remaining two years of my PhD!

 

You can follow my journey by reading my blog and keeping up with me on Twitter (@sciencedestiny).

 

References:

[1] Westwood, J. H. et al. (2010). The evolution of parasitism in plants. Trends in Plant Science, 15(4): 227-235.

[2] Scholes, J. D. and Press, M. C. (2008). Striga infestation of cereal crops – an unsolved problem in resource limited agriculture. Current Opinion in Plant Biology, 11(2): 180-186.

Student-driven plant breeding symposium addresses global challenges in the 21st century

This week we spoke to Francisco Gomez and Ammani Kyanam, graduate students in the Soil and Crop Science Department at Texas A&M University, USA. They were part of the organizing committee for the recent Texas A&M Plant Breeding Symposium, a successful meeting run entirely by students at the University.

Francisco Gomez and Ammani Kyanam

Francisco Gomez and Ammani Kyanam, part of the student organizing committee of the Plant Breeding Symposium

Could you begin with a brief introduction to the Plant Breeding Symposium held at Texas A&M in February?

Texas A&M University is one of the largest academic and public plant breeding institutions worldwide, which trains breeders in a variety of programs. Every year, students at the University organize the Texas A&M Plant Breeding Symposium, which is part of the DuPont Pioneer series of symposia. The symposium provides a platform for graduate students to bridge the interaction between the public and private sectors and engage in conversations about the grand challenges facing humanity that could be addressed by plant breeding. It’s also a great chance to network with faculty, students, and industry representatives.

 

Could you tell us more about this theme and how the different sessions were chosen?

We wanted the theme of the meeting to mirror the university’s goal of thinking big to pinpoint solutions to modern global challenges using plant science and breeding. Every member of the committee had the opportunity propose a theme, which were then put to a vote.

Nikolai Vavilov

Nikolai Vavilov, a Russian botanist and geneticist, was the inspiration for this year’s symposium. Image credit: Public Domain.

This year’s theme, “The Vavilov Method: Utilizing Genetic Diversity”, celebrated the life and career of Russian botanist Nikolai Vavilov, who identified the centers of origin of cultivated plants. We invited plant scientists and breeders who are applying Vavilov’s ideas through the conservation, collection, and effective utilization of genetic diversity in modern crop breeding programs. This year we also developed a workshop entitled “Where does a breeder go to find genetic diversity?”, which allowed students and faculty to talk about the importance of utilizing genetic diversity in crop improvement and to learn new tools to help them incorporate genetic diversity in breeding programs.

 

Could you tell us more about how you developed the workshop?

Our aim for the workshop was to engage students and faculty on where we can find genetic diversity, how we can use it, and to include a panel discussion on the challenges and the future of genetic diversity in modern plant breeding programs. As a new value-added event, the workshop was challenging to set up because it required a different set of skills to the rest of the meeting. Once we had an idea of what we wanted, we set up an initial meeting with our speakers where we brainstormed ideas. After several online meetings and e-mails with Professor Paul Gepts (UC Davis), Dr. Colin Khoury (Agricultural Research Service, USDA; check out his recent GPC blog here!), and Professor Susan McCouch (Cornell University), we finalized the structure of the workshop, the layout of the sessions, and the objectives for the speakers. We also had a representative from DivSeek, Dr. Ruth Bastow, on the discussion panel, who contributed to our discussion on future tools for accessing diversity in the future.

 

How has the symposium grown since the inaugural meeting in 2015?

Every year we want to make the symposium a memorable event, and we want other students and faculty to really get something out of it. We are learning more and more about the students and faculty with these events, particularly in terms of which topics are the most exciting or interesting. The symposium has also grown into a two-day event, with this year’s inclusion of the workshop.

 

Did you have to overcome any challenges in the organization of the event?

One of our biggest challenges was to secure funding for the event, which is free to attend. To add further value to our event, we wanted to have additional components such as a student research competition and/or workshop, which meant we had to aggressively fundraise from multiple sources. This involved writing a lot of grant proposals both to plant sciences departments across Texas A&M University, as well as to other sources of external funding.

We are grateful to DuPont Pioneer for providing a large amount of the funding. In 2017, we also received sponsorship from the Texas Institute for Genomic Science and Society, Departments of Soil and Crop Sciences, Molecular and Environmental Plant Science, Horticulture, Plant Pathology, and Biology, Texas Grain Sorghum Association, Texas Peanut Producers Board, and Cotton Incorporated. Our beverage sponsor was Pepsi and Kind Snacks was our snack sponsor.

 

What advice would you give a graduate student trying to organize a similar event?

Plan early and set small goals! Communication is key for a large team to organize such an event. We encourage groups to use Slack or some sort of team work interface. It really helped us to be in constant communication with each other during the months leading up to the symposium.

 

Could you tell us a little about your own research?

My research (Francisco Gomez) is focused on identifying genomic regions (known as quantitative trait loci; QTLs) associated with mechanical traits that are known to be associated with stem lodging, a major agronomic problem that reduces yields worldwide. My colleague and co-chair, Ammani Kyanam, received her Masters in Plant Breeding in while working in the cotton cytogenetics program in our department. Her research focused on developing genomic tools to facilitate the development of Chromosome Segment Substitution Lines for upland cotton. She is currently mapping QTLs for aphid resistance in sorghum for her Ph.D. You can learn more about the research of our individual committee members at http://plantbreedingsymposium.com/committee/.

 

How can our readers connect with you?

We have a strong social media presence via Facebook, Instagram and YouTube, where we post event videos, photos and periodical updates. Check them out below!

Facebook: TAMUPBsymposium

Instagram: @pbsymposium

Twitter: @pbsymposium

YouTube: Texas A&M Plant Breeding Symposium

Website: plantbreedingsymposium.com

Email: mailto:[email protected]

Healthy soil is the real key to feeding the world

By David R. Montgomery, University of Washington

 

Image 20170329 8557 1q1xe1z
Planting a diverse blend of crops and cover crops, and not tilling, helps promote soil health. Catherine Ulitsky, USDA/Flickr, CC BY

 

One of the biggest modern myths about agriculture is that organic farming is inherently sustainable. It can be, but it isn’t necessarily. After all, soil erosion from chemical-free tilled fields undermined the Roman Empire and other ancient societies around the world. Other agricultural myths hinder recognizing the potential to restore degraded soils to feed the world using fewer agrochemicals. The Conversation

When I embarked on a six-month trip to visit farms around the world to research my forthcoming book, “Growing a Revolution: Bringing Our Soil Back to Life,” the innovative farmers I met showed me that regenerative farming practices can restore the world’s agricultural soils. In both the developed and developing worlds, these farmers rapidly rebuilt the fertility of their degraded soil, which then allowed them to maintain high yields using far less fertilizer and fewer pesticides.

Their experiences, and the results that I saw on their farms in North and South Dakota, Ohio, Pennsylvania, Ghana and Costa Rica, offer compelling evidence that the key to sustaining highly productive agriculture lies in rebuilding healthy, fertile soil. This journey also led me to question three pillars of conventional wisdom about today’s industrialized agrochemical agriculture: that it feeds the world, is a more efficient way to produce food and will be necessary to feed the future.

Myth 1: Large-scale agriculture feeds the world today

According to a recent U.N. Food and Agriculture Organization (FAO) report, family farms produce over three-quarters of the world’s food. The FAO also estimates that almost three-quarters of all farms worldwide are smaller than one hectare – about 2.5 acres, or the size of a typical city block.

 

A Ugandan farmer transports bananas to market. Most food consumed in the developing world is grown on small family farms.Svetlana Edmeades/IFPRI/Flickr, CC BY-NC-ND

 

Only about 1 percent of Americans are farmers today. Yet most of the world’s farmers work the land to feed themselves and their families. So while conventional industrialized agriculture feeds the developed world, most of the world’s farmers work small family farms. A 2016 Environmental Working Group report found that almost 90 percent of U.S. agricultural exports went to developed countries with few hungry people.

Of course the world needs commercial agriculture, unless we all want to live on and work our own farms. But are large industrial farms really the best, let alone the only, way forward? This question leads us to a second myth.

Myth 2: Large farms are more efficient

Many high-volume industrial processes exhibit efficiencies at large scale that decrease inputs per unit of production. The more widgets you make, the more efficiently you can make each one. But agriculture is different. A 1989 National Research Council study concluded that “well-managed alternative farming systems nearly always use less synthetic chemical pesticides, fertilizers, and antibiotics per unit of production than conventional farms.”

And while mechanization can provide cost and labor efficiencies on large farms, bigger farms do not necessarily produce more food. According to a 1992 agricultural census report, small, diversified farms produce more than twice as much food per acre than large farms do.

Even the World Bank endorses small farms as the way to increase agricultural output in developing nations where food security remains a pressing issue. While large farms excel at producing a lot of a particular crop – like corn or wheat – small diversified farms produce more food and more kinds of food per hectare overall.

Myth 3: Conventional farming is necessary to feed the world

We’ve all heard proponents of conventional agriculture claim that organic farming is a recipe for global starvation because it produces lower yields. The most extensive yield comparison to date, a 2015 meta-analysis of 115 studies, found that organic production averaged almost 20 percent less than conventionally grown crops, a finding similar to those of prior studies.

But the study went a step further, comparing crop yields on conventional farms to those on organic farms where cover crops were planted and crops were rotated to build soil health. These techniques shrank the yield gap to below 10 percent.

The authors concluded that the actual gap may be much smaller, as they found “evidence of bias in the meta-dataset toward studies reporting higher conventional yields.” In other words, the basis for claims that organic agriculture can’t feed the world depend as much on specific farming methods as on the type of farm.

 

Cover crops planted on wheat fields in The Dalles, Oregon.
Garrett Duyck, NRCS/Flickr, CC BY-ND

 

Consider too that about a quarter of all food produced worldwide is never eaten. Each year the United States alone throws out 133 billion pounds of food, more than enough to feed the nearly 50 million Americans who regularly face hunger. So even taken at face value, the oft-cited yield gap between conventional and organic farming is smaller than the amount of food we routinely throw away.

Building healthy soil

Conventional farming practices that degrade soil health undermine humanity’s ability to continue feeding everyone over the long run. Regenerative practices like those used on the farms and ranches I visited show that we can readily improve soil fertility on both large farms in the U.S. and on small subsistence farms in the tropics.

I no longer see debates about the future of agriculture as simply conventional versus organic. In my view, we’ve oversimplified the complexity of the land and underutilized the ingenuity of farmers. I now see adopting farming practices that build soil health as the key to a stable and resilient agriculture. And the farmers I visited had cracked this code, adapting no-till methods, cover cropping and complex rotations to their particular soil, environmental and socioeconomic conditions.

Whether they were organic or still used some fertilizers and pesticides, the farms I visited that adopted this transformational suite of practices all reported harvests that consistently matched or exceeded those from neighboring conventional farms after a short transition period. Another message was as simple as it was clear: Farmers who restored their soil used fewer inputs to produce higher yields, which translated into higher profits.

No matter how one looks at it, we can be certain that agriculture will soon face another revolution. For agriculture today runs on abundant, cheap oil for fuel and to make fertilizer – and our supply of cheap oil will not last forever. There are already enough people on the planet that we have less than a year’s supply of food for the global population on hand at any one time. This simple fact has critical implications for society.

So how do we speed the adoption of a more resilient agriculture? Creating demonstration farms would help, as would carrying out system-scale research to evaluate what works best to adapt specific practices to general principles in different settings.

We also need to reframe our agricultural policies and subsidies. It makes no sense to continue incentivizing conventional practices that degrade soil fertility. We must begin supporting and rewarding farmers who adopt regenerative practices.

Once we see through myths of modern agriculture, practices that build soil health become the lens through which to assess strategies for feeding us all over the long haul. Why am I so confident that regenerative farming practices can prove both productive and economical? The farmers I met showed me they already are.

David R. Montgomery, Professor of Earth and Space Sciences, University of Washington

This article was originally published on The Conversation. Read the original article.

Roots of a second green revolution

This week we spoke to Professor Jonathan Lynch, Penn State University, whose research on root traits has deepened our understanding of how plants adapt to drought and low soil fertility.

 

 

Could you begin by giving us a brief introduction to your research?

We are trying to understand how plants adapt to drought and low soil fertility. This is important because all plants in terrestrial ecosystems experience suboptimal water and nutrient availability, so in rich nations we maintain crop yields with irrigation and fertilizer, which is not sustainable in the long term. Furthermore, climate change is further degrading soil fertility and increasing plant stress. This topic is therefore both a central question in plant evolution and a key challenge for our civilization. We need to develop better ways to sustain so many people on this planet, and a big part of that will be developing more resilient, efficient crop plants.

 

Drought is devastating for crops

Drought and low soil fertility are devastating for crops. Image credit: CIAT. Used under license: CC BY-SA 2.0.

 

What got you interested in this field, and how has your career developed over time?

When I was 9 years old I became aware of a famine in Africa related to crop failure and resolved to do something about it. I studied soils and plant nutrition as an undergraduate, and in graduate school worked on plant adaptation to low phosphorus and salinity stress, moving to a research position at the CIAT headquarters in Colombia. Later I moved to Penn State, where I have maintained this focus, working to understand the stress tolerance of staple crops, and collaborating with crop breeders in the USA, Europe, Africa, Asia, and Latin America.

 

Your recent publications feature a variety of different crop plants. Could you talk about how you select a species to study?

We work with species that are important for food security, that grow in our field environments, and that I think are cool. We have devoted most of our efforts to the common bean – globally the most important food legume – and maize, which is the most important global crop. These species are often grown together in Africa and Latin America, and part of our work has been geared to understanding how maize/bean and maize/bean/squash polycultures perform under stress. These are fascinating, beautiful plants with huge cultural importance in human history. They are also supported by talented, cooperative research communities. One nice feature of working with food security crops is that their research communities share common goals of achieving impact to improve human welfare.

 

Common bean (Phaseolus vulgaris)

The common bean (Phaseolus vulgaris) is an important staple in many parts of the world. Image credit: Ervins Strauhmanis. Used under license: CC BY 2.0.

 

Many researchers use Arabidopsis thaliana for plant research, but are crops better suited for root research than the delicate roots of Arabidopsis? Are crop plants more or less difficult to work with in your research than Arabidopsis?

The best research system is entirely a function of your goals and questions. We have worked with Arabidopsis for some questions. Since we work with processes at multiple scales, including crop stands, whole organisms, organs, tissues, and cells, it has been useful to work with large plants such as maize, which are large enough to easily measure and to work with in the field. The most interesting stress adaptations for crop breeding are those that differ among genotypes of the same species, and at that level of organization there is a lot of biology that is specific to that species, that cannot readily be generalized from model organisms with very different life strategies. There has been considerable attention to model genomes and much less attention to model phenomes.

 

You have developed methodologies for the high-throughput phenotyping of crop plants. What does this technique involve and what challenges did you have to overcome to succeed?

We have developed multiple phenotyping approaches – too many to summarize readily here. Our overall approach is simply to develop a tool that helps us achieve our goals. For example, we have developed tools to quantify the root architecture of thousands of plants in the field, to measure anatomical phenotypes of thousands of samples from field-grown roots, to help us determine which root phenotypes might affect soil resource capture, etc. Working with geneticists and breeders, we are constantly asked to measure something meaningful on thousands of plants in a field, in many fields, every season. ARPA-E (the US Advanced Research Projects Agency for Energy) has recently funded us to develop phenotyping tools for root depth in the field, but this is the first time we have been funded to develop phenotyping tools – generally we just come up with things to help us do our work, which fortunately have been useful for other researchers as well.

 

Could you talk about some of the computational models you have developed for investigating plant growth and development?

The biological interactions between plants and their environment are so complex, we need computational (in silico) tools to help us evaluate them. Increasingly, in silico tools can integrate information across multiple scales, from gene expression to crop stands. These tools also allow us to evaluate things that are difficult to measure, such as phenotypes that do not yet exist, or future climates. In silico biology will be an essential tool in 21st Century biology, which will have access to huge amounts of data at multiple scales that can be used to try to understand incredibly complex systems, such as the human brain or roots interacting with living soil. Our main in silico tool is SimRoot, developed over the past 25 years to understand how root phenotypes affect soil resource capture.

Check out a SimRoot model below:


 

You have been working on breeding plants that have improved yield in soils with low fertility. What have you achieved in this work?

In collaboration with crop breeders and colleagues in various nations we have developed improved common bean lines with better yield under drought and low soil fertility that are being deployed in Africa and Latin America, improved soybean lines with better yield in soils with low phosphorus being deployed in Africa and Asia, and are now working with maize breeders in Africa to develop lines with better yield under drought and low nitrogen stress. Many crop breeders are using our methods for root phenotyping to target root phenotypes in their selection regimes in multiple crops.

 

What piece of advice do you have for early career researchers?

You are at the forefront of an unprecedented challenge we face as a species – how to sustain 10 billion people in a degrading environment. Plant biologists are an essential part of the effort to reshape how we live on this planet. Do not doubt the importance of your efforts. Do not lose sight of the very real human impact of your scientific choices. Do not be deterred by the gamesmanship and ‘primate politics’ of science. You can make a difference. We need you.

Global Plant Council stress resilience commentaries published in Food and Energy Security

In October 2015, researchers from around the world came together in Iguassu Falls, Brazil, for the Stress Resilience Symposium, organized by the Global Plant Council and the Society for Experimental Biology (SEB), to discuss the current research efforts in developing plants resistant to the changing climate. (See our blog by GPC’s Lisa Martin for more on this meeting!)

Building on the success of the meeting, the Global Plant Council team and attendees compiled a set of papers to provide a powerful call to action for stress resilience scientists around the world to come together to tackle some of the biggest challenges we will face in the future. These four papers were published in the Open Access journal Food and Energy Security alongside an editorial about the Global Plant Council.

In the editorial, the Global Plant Council team (Lisa Martin, Sarah Jose, and Ruth Bastow) introduce readers to the Global Plant Council mission, and describe the Stress Resilience initiative, the meeting, and introduce the papers that came from it.

In the first of the commentaries, Matthew Gilliham (University of Adelaide), Scott Chapman (CSIRO), Lisa Martin, Sarah Jose, and Ruth Bastow discuss ‘The case for evidence-based policy to support stress-resilient cropping systems‘, commenting on the important relationships between research and policy and how each must influence the other.

Global Plant Council President Bill Davies (Lancaster University) and CIMMYT‘s Jean-Marcel Ribaut outline the ways in which research can be translated into locally adapted agricultural best practices in their article, ‘Stress resilience in crop plants: strategic thinking to address local food production problems‘.

In the next paper, ‘Harnessing diversity from ecosystems to crops to genes‘, Vicky Buchanan-Wollaston (University of Warwick), Zoe Wilson (University of Nottingham), François Tardieu (INRA), Jim Beynon (University of Warwick), and Katherine Denby (University of York) describe the challenges that must be overcome to promote effective and efficient international research collaboration to develop new solutions and stress resilience plants to enhance food security in the future.

University of Queensland‘s Andrew Borrell and CIMMYT‘s Matthew Reynolds discuss how best to bring together researchers from different disciplines, highlighting great examples of this in their paper, ‘Integrating islands of knowledge for greater synergy and efficiency in crop research‘.

In all of these papers, the authors suggest practical short- and long-term action steps and highlight ways in which the Global Plant Council could help to bring researchers together to coordinate these changes most effectively.

Read the papers in Food and Energy Security here.

Lentils under the lens: Improving genetic diversity for sustainable food security

This week’s post comes to us from Crystal Chan, project manager of the Application of Genomic Innovation in the Lentil Economy project led by Dr. Kirstin Bett at the Department of Plant Sciences, University of Saskatchewan.

 

Could you begin with a brief introduction to your research?

Our research focuses on the smart use of diverse genetic materials and wild relatives in the lentil (Lens culinaris) breeding program.

Canada has become the world’s largest producer and exporter of lentils in recent years. Lentils are an introduced species to the northern hemisphere and, until recently, our breeding program at the University of Saskatchewan involved just a handful of germplasms adapted to our climatic condition. With dedicated breeding efforts we have achieved noteworthy genetic gains in the past decade, but we are missing out on the vast genetic diversity available within the Lens genus. This is a major dilemma faced by all plant breeders: do we want consistency (sacrificing genetic diversity and reducing genetic gains over time) or diversity (sacrificing some important fixed traits and spending lots of time and resources in “backcrossing/rescue efforts”)?

 

In our current research, we use genomic tools to understand the genetic variability found in different lentil genotypes and the basis of what makes lentils grow well in different global environments (North America vs. Mediterranean countries vs. South Asian countries). We will then develop molecular breeding tools that breeders can use to improve the diversity and productivity of Canadian lentils while maintaining their adaptation to the northern temperate climate.

 

What first led you to this research topic?

Dr. Albert (Bert) Vandenberg, professor and lentil breeder at the University of Saskatchewan, noticed one of the wild lentil species was resistant to several diseases that devastate the cultivated lentil. After years of dedicated breeding effort, he was able to transfer the resistance traits to the cultivated lentil, but it took a lot of time and resources. We began looking into other beneficial traits and became fascinated with the domestication and adaptation aspects of lentil – after all lentil is one of the oldest cultivated crops, domesticated by man around 11,000 BC! With the rapid advance in genomic technology, we can start to better understand the biology and develop tools to harness these valuable genetic resources.

 

You have been involved in the development of tools that assist researchers to build databases of genomics and genetics data. Could you tell us more about projects such as Tripal?

Over the past six years, Lacey Sanderson (bioinformaticist in our group) has developed a database for our pulse research program at the University (Knowpulse, http://knowpulse.usask.ca/portal/). The database is specifically designed to present data that is relevant to breeders, as our group has a strong focus on variety development for the Canadian pulse crop industry. Knowpulse houses genotypic information from past and on-going lentil genomics projects, and includes tools for looking up genotypes as well as comparing the current genome assembly (currently v1.2) and other sequenced legume genomes. The tools are being developed in Tripal, an open-source toolkit that provides an interface between the data and a Drupal web content management system, in collaboration with colleagues at Washington State University.

 

At the moment we are developing new functionalities that will allow us to store and present germplasm information as well as phenotypic data. We are also working with our colleagues at Washington State University (under the “Tripal Gateway Project” funded by the National Science Foundation) to enhance interconnectivity between Knowpulse and other legume databases, such as the Legume Information Service (LIS) and Soybase, to facilitate comparative genomic studies.

How challenging are pulse genomes to assemble? How closely related are the various crops?

We had the fortune to lead the lentil genome sequencing initiative thanks to the support from producer groups and governments across the globe.  The lentil genome is really challenging to assemble! We see nice synteny between lentil and the model legume, medicago, however the lentil genome is much bigger. We see a significant increase in genome size between chickpea and beans versus lentil (and pea for that matter), yet we have evidence to show that genome duplication is not the cause of the size increase. There are a lot of very long repetitive elements sprinkled around the genome, which makes its sequencing and proper assembly very challenging. Not to mention understanding the role of these long repetitive elements in biological functions…

 

What insights into crop domestication have you gained from these genomes?

That’s what we are working on right now under the AGILE (“Application of Genomics to Innovation in the Lentil Economy”) project. Stay tuned!

 

Do you work with breeders to develop new cultivars? What sorts of traits are most important? 

Breeding is at the core of our work – both Kirstin and Bert are breeders (Kirstin has an active dry bean breeding program when she’s not busy with genomic research). All our research aims to feed information to the breeders so that they can make better crossing and selection decisions. Our work in herbicide tolerance has led to the development and implementation of a molecular marker to screen for herbicide resistance. With that marker we save time (skipping a crossing cycle) and forego the herbicide spraying test for all of our early materials.

Disease resistance and drought tolerance are also important for the growers. Visual quality (seed shape, size, color) are very important too as our customers are very picky as to what sort of lentils they like to buy/eat.

What does the future of legume/lentil agriculture hold?

Lentils have been a staple food in many countries for centuries and have been gaining popularity in North America in recent years as people are looking for plant-based protein sources. Lentils are high in fibre, protein, and complex carbohydrates, while low in fat and calories, and have a low glycemic index. They are suitable for vegetarian/vegan, gluten-free, diabetic, and heart-smart diets. Lentils also provide essential micronutrients such as iron, zinc and folates. Lentils are widely recognized as nutrient-dense food that could serve as part of the solution to combat global food and nutritional insecurity.

In modern agriculture, adding lentil or other leguminous crops in the crop rotation helps improve soil structure, soil quality, and biotic diversity, as well as enhancing soil fertility through their ability to fix nitrogen. Because pulse crops require little to no nitrogen fertilizer, they use half of the non-renewable energy inputs of other crops, reducing greenhouse gas emissions.

2016 was marked by the United Nations as the International Year of Pulses, which was great as many people have become more aware of the benefits of pulse crops on the plate and in the field.

 

Follow us on twitter (@Wildlentils) for research updates!

 

All images are credited to Mr Derek Wright.

Sustainable, resilient, and nutritious food production with N8 AgriFood

This week we spoke with Dr Sally Howlett, a Knowledge Exchange Fellow with the N8 AgriFood Programme. (More on Sally at the end).

Sally, what is the N8 AgriFood Programme? When and why was it established?

The N8 Research Partnership is a collaboration of the eight most research-intensive universities in the North of England, namely Durham, Lancaster, Leeds, Liverpool, Manchester, Newcastle, Sheffield, and York. It is a not-for-profit organization with the aim of bringing together research, industry and society in joint initiatives. These partners have a strong track record of working together on large-scale, collaborative research projects, one of which is the N8 AgriFood Programme. This £16M multi-disciplinary initiative is funded by the N8 partners and HEFCE (The Higher Education Funding Council for England), and was launched in 2015 to address three key global challenges in Food Security: sustainable food production, resilient food supply chains, and improved nutrition and consumer behavior.

How does plant science research fit into the N8 AgriFood Programme?

There is a strong motivation to ‘think interdisciplinary’ when it comes to developing projects for the N8 AgriFood Programme; therefore, whilst the most obvious home for plant science may be within the theme of sustainable food production, e.g. crop improvement, we see no boundaries when it comes to integrating fundamental research in plant science with applications in all three of our research themes. The testing of research ideas in the ‘real world’ is supported by the five University farms within the N8, which include arable and livestock holdings.

We are launching a Crop Innovation Pipeline to assist with the translation of research into practical applications, with the first event taking place in Newcastle on 2nd-3rd May 2017. It is an opportunity for scientists from academia and industry and representatives from the farming community to discuss their ideas for the implementation of plant biology research into on-farm crop improvement strategies.

How is the work split between the different institutions? How is such a large-scale initiative managed?

Whilst there are many areas of shared expertise between the eight partner institutions, each also has its own areas of specialism within the agri-food arena. The strength of the N8 AgriFood Programme is in working collaboratively to identify complementary strengths and grow those areas in a synergistic way. In this way, we are collectively able to tackle research projects that would not be possible for a single university alone. Pump-priming funds are available at a local and strategic level to support this kick-starting of new multi-institution projects. The Programme itself is led out of the University of York, and each University has its own N8 AgriFood Chair in complementary areas across the Programme. Having both inward- and outward-facing roles, they work with the Knowledge Exchange Fellows and the Programme Lead for each theme to ensure activities at their own institute are connected with what is going on in the wider N8.

What does your work as a Knowledge Exchange Fellow entail?

As a Knowledge Exchange Fellow within the N8 AgriFood Programme, my initial contact with people usually begins with the question ‘What on earth does a Knowledge Exchange Fellow do?’ – and it can be quite difficult to answer! Although some form of knowledge transfer activity has been a defined output of research projects for some time now, knowledge exchange as an ongoing two-way dialogue between researchers and external stakeholders to enable a co-creation process has been less common until recently. Hence dedicated Knowledge Exchange Fellows with academic training are a relatively ‘new’, but growing, phenomenon.

My role is best described as acting as a bridge between the research community and non-academics with a vested interest in developing or using the findings of the research process. It is key to have a good understanding of the perspectives of all parties involved and be able to translate this into the appropriate language for a particular sector. Each of the N8 institutes has appointed Knowledge Exchange Fellow(s), and we work as a cohort to keep abreast of the latest developments in our fields in order to support the development of relationships and innovative projects. In such a huge undertaking, the phrase ‘there is strength in numbers’ is certainly apposite!

 

How does N8 AgriFood interact with companies?

N8 Agrifood engages with UK-based companies in many ways, including individual face-to-face meetings, attending and hosting networking events, participating in national exhibitions, and holding business-facing conferences. We also run a series of Industry Innovation Forums on various topics throughout the year. These provide a unique opportunity to discuss key challenges, identify problems and deliver new insights into innovation for agri-food, matching practical and technical industry challenges with the best research capabilities of the N8 universities.

 

How does N8 Agrifood interact with farmers?

As the engine of the agri-food industry, the views and collective experience of the farming community are vitally important in shaping the direction and content of the projects we develop. Co-hosting events with programs such as the ADAS Yield Enhancement Network (YEN), which involves over 100 farms, is one way that we connect with the sector. We are also working with agricultural societies to promote what we are doing and engage directly with their networks of farming members, e.g. the Yorkshire Agricultural Society’s Farmer Scientist Network. Last year we gave a series of seminars at the Great Yorkshire Show and are keen to encourage further collaboration with practicing farmers and growers across the UK.

 

Does N8 AgriFood collaborate with other research institutes around the world?

The N8 AgriFood Programme has strong international connections and actively welcomes working with international research institutes. Given the interconnectedness of our global food system, we feel that it is vital to link with overseas partners and that real impact can be had by bringing together top researchers from other countries to work together on problems. The value of N8 AgriFood as a one-stop shop is that we represent a large breadth and depth of expertise under a single umbrella, which greatly facilitates collaborating and finding suitable collaboration partners. Our pump-priming funds are a way for researchers to initiate new international partnerships, and we are also working to build links with global research organizations who have shared interests. For example, we recently visited Brazil and China to explore specific opportunities for collaboration and leveraging of research expertise and facilities, and are currently organizing a workshop in Argentina in March.

 

Where can readers get more information?

If you’d like to find out more, please visit our website: http://n8agrifood.ac.uk/, or consider attending one of our upcoming events:

 

All images are credited to the N8 Agrifood Programme.


Dr Sally Howlett is a Knowledge Exchange Fellow with the N8 AgriFood Programme. Her research background is in sustainable crop production and plant pest management.  After working on the control of invertebrate crop pests in New Zealand for several years, she returned to on-farm research in the UK and extended her focus to include the crops themselves taking a whole-systems view and comparing performance under conventional, organic and agroforestry management approaches. Sally’s role within N8 AgriFood provides a great opportunity to use her experience of agriculture and working with different actors across the sector to engage with external stakeholders, co-producing ideas and multi-disciplinary projects with applications throughout the agrifood chain.

Chickpea innovation: Revisiting the origins of crops to solve the challenges of modern agriculture

Doug Cook

Professor Doug Cook

This post was written by Professor Doug Cook (University of California, Davis), the Director of the Feed the Future Innovation Lab for Climate Resilient Chickpea. His current research spans both model and crop legume systems from a cellular to an ecosystem scale. 

 

The origins of modern human society derive, in large part, from the transition to an agrarian lifestyle that occurred in parallel at multiple locations around the world, including ~10,000 years ago in Mesopotamia*. Early agriculturalists wrought a revolution that would define human trajectory to the current day, domesticating wild plant and animal species into crops and livestock. The wild progenitors of chickpea, for example, were among a handful of Mesopotamian neo-crops, brought from hilly slopes into more fertile and cultivable plains and river valleys. In doing so, these farmers selected a small number of useful traits largely based on natural mutations that made wild forms amenable to agriculture, such as the consistency of flowering, upright growth, and seeds that remained attached to plants rather than dispersing.

Chickpea innovation

Doug Cook collecting chickpeas

Collecting wild chickpea plants, soil, and seed in southeastern Turkey. Image credit: Chickpea Innovation lab.

An unintended consequence of crop domestication was the loss of the vast majority of genetic diversity found in the wild populations. The Feed the Future Innovation Lab for Climate Resilient Chickpea at the University of California, Davis (Chickpea Innovation Lab) documented a ~95% loss of genetic variation from wild species to modern elite varieties. This reduction in genetic variation constrains our ability to adapt the chickpea crop to the range of challenges facing modern agriculture.

The Chickpea Innovation Lab is re-awakening the untapped potential of wild chickpea and directing that potential to solve global problems in agriculture, especially in the developing world.  Combining longstanding practices in ecology with the remarkable power of genomics and sophisticated computational methods, we have spanned the gap from the wild systems to cultivated crops. Beginning with the analysis of ~2,000 wild genomes, the simple technology of genetic crosses applied at massive scale has delivered a large and representative suite of wild variation into agricultural germplasm. These traits are now being actively used for phenotyping and breeding in the U.S., India, Ethiopia and Turkey, and our team is currently prospecting for tolerance to drought, heat and cold; increased pest and disease resistance; improved seed nutritional content; nitrogen fixation; plant architecture; and yield.

Characterizing wild germplasm

Sultan Mohammed Yimer

Visiting Ethiopian student, Sultan Mohammed Yimer investigating disease resistance in wild chickpea. Image credit: Chickpea Innovation lab.

Along the way, the Chickpea Innovation Lab has deposited wild germplasm into the multi-lateral system, providing open access to a treasure trove of genetic variation. The Chickpea Innovation Lab derives support from numerous sponsors whose funds enable the collection, characterization, and utilization of this vital germplasm resource.

International research

A unique strength of the lab is that our diverse sponsorship permits activities ranging from fundamental scientific investigation to applied agricultural research and product development.

An additional objective of the Lab is to train and educate students in the developing world. Towards that end, 18 international and nine domestic students, postdoctoral scientists and visiting faculty have received training in disciplines ranging from computational biology, plant pathology and entomology, to agricultural microbiology, and molecular genetics and breeding.

Chickpea breeding

Harvesting progeny derived by crossing wild and cultivated chickpea plants in Davis, California. Image credit: Chickpea Innovation lab.

* Mesopotamia, literally “between the rivers”, is the region of modern day southeastern Turkey, bounded by the Tigris and Euphrates rivers.

 

RNA clay offers green alternative to plant pesticides

By Neena Bhandari

A nano-sized bio-degradable clay-comprising double stranded ribonucleic acid (dsRNA) could offer a cost-effective, clean and green alternative to chemical-based plant pesticides.

Australian researchers from the University of Queensland have successfully used a gene-silencing spray, named BioClay, a combination of biomolecules and clay, to protect tobacco plants from a virus for 20 days with a single application. Their study has been published in Nature Plants.

“When BioClay is sprayed onto a plant, the virus-specific dsRNA is slowly released from the clay nanosheets into the plant. This activates a pathway in the plant that is a natural defence mechanism. The dsRNA is chopped up into small bits of RNA by enzymes of this pathway. These small bits attack the virus when it infects the plant without altering the plant genome,” explains lead researcher, Neena Mitter.

“Even with current pesticides, we lose up to 40 per cent of our crop productivity because of pests and pathogens. We are hoping that having BioClay in the mix as an environmentally friendly, sustainable crop protection measure will reduce crop losses,” Mitter adds.

“The clay-based delivery technology could represent a positive inflection point in the progress towards commercialisation of topical RNAi. This is a non-GM, environmentally benign and very specific technology.”

 John Killmer, APSE

While chemical-based pesticides kill the targeted insect, they can also affect a range of other insects that are beneficial. Mitter says, “BioClay is specific and it only kills the pathogen being targeted. Currently farmers use insecticides to kill the vector that comes with the viruses, but with BioClay we can target the virus itself.”

BioClay field trials may begin in Australia by year-end. “The first test will be on a virus that infects vegetable crops — capsicum, tomato, chilli,” Mitter tells SciDev.Net.

Farmers can use the existing equipment to deliver BioClay and the researchers are hopeful that it will be a commercially viable product for farmers everywhere. The clay component is cheap to make, but not the RNA.

Several companies like APSE, a US based startup, are working on the mass production of RNAs. APSE is developing RNA manufacturing technology for RNA interference (RNAi) or gene silencing applications.

“Our technology for RNA production should be ready in 2-3 years. We are targeting US$2 per gram,” APSE’s John Killmer tells SciDev.Net.

Killmer says, “The clay-based delivery technology could represent a positive inflection point in the progress towards commercialisation of topical RNAi. This is a non-GM, environmentally benign and very specific technology.”

RNAi technology is being used by many in the agriculture industry including the biotech firm Monsanto. The company’s BioDirect technology is focused on applications of RNAi directly onto the leaves of a plant.

Monsanto’s spokesperson John Combest tells SciDev.Net, “As insects develop resistance to certain classes of pesticides, giving farmers another option to control these pests is critical. The idea is not to replace any given system of farming, whether modern GM systems or others — it’s to provide farmers with products that can complement or replace agricultural chemical products.”

This piece was produced by SciDev.Net’s Asia & Pacific desk.

 

This article was originally published on SciDev.Net. Read the original article.

Mother grain genome: insights into quinoa

Sales of quinoa (Chenopodium quinoa) have exploded in the last decade, with prices more than tripling between 2008 and 2014. The popularity of this pseudocereal comes from its highly nutritious seeds, which resemble grains and contain a good balance of protein, vitamins, and minerals. The nourishing nature of quinoa meant it was prized by the Incas, who called it the “Mother grain”.

Quinoa

Quinoa is a popular ‘grain’, but it is more closely related to spinach and beetroot than cereals like wheat or barley. Image credit: Flickr user. Used under license: CC BY 2.0.

Quinoa is native to the Andes of South America, where it thrives in a range of conditions from coastal regions to alpine regions of up to 4000 m above sea level. Its resilience and nutritious seeds means that quinoa has been identified as a key crop for enhancing food security, but there are currently very few breeding programs targeting this species.

The challenge of improving the efficiency and sustainability of quinoa production has so far been restricted by the lack of a reference genome. This week, a team of researchers led by Professor Mark Tester (King Abdullah University of Science & Technology; KAUST) addressed this issue, publishing a high-quality genome sequence for quinoa in Nature. They compared the genome with that of related species to characterize the evolution and domestication of the crop, and investigated the genetic diversity of economically important traits.

 

The evolution of quinoa

Tester and colleagues used an array of genomics techniques to assemble 1.39 Gb of the estimated 1.45-1.50 Gb full length of quinoa’s genome. Quinoa is a tetraploid, meaning it has four copies of each chromosome. The researchers shed light on the evolutionary history of this crop by sequencing descendants of the two diploid species (each containing two sets of chromosomes) that hybridized to generate quinoa; kañiwa (Chenopodium pallidicaule) and Swedish goosefoot (Chenopodium suecicum). Comparing these sequences to quinoa and other relatives, the team showed that the hybridization event likely occurred between 3.3 and 6.3 million years ago. A comparison with other closely related Chenopodium species also suggested that, contrary to previous predictions, quinoa may have been domesticated twice, both in highland and coastal environments.

Quinoa field

Quinoa field. Image credit: LID. Used under license: CC BY-SA 2.0.

 

Washing away quinoa’s bitter taste

Quinoa seeds are coated with soap-like chemicals called saponins, which have a bitter taste that deters herbivores. Saponins can disrupt the cell membranes of red blood cells, so they have to be removed before human consumption, but this process is costly, so quinoa breeders are always looking for varieties that produce lower levels of saponins.

Sweet (low-saponin) quinoa strains do occur naturally, but the genes that regulate this phenotype were previously unknown. Tester and colleagues investigated sweet and bitter quinoa strains and discovered that a single gene (TRITERPENE SAPONIN BIOSYNTHESIS ACTIVATING REGULATOR-LIKE 1 [TSARL1]) controls the amount of saponins produced in the seeds. The low-saponin quinoa strains contained mutations in TSARL1 that prevented it from functioning properly. This is a key target for the improvement of quinoa in the future, although farmers will have to find new ways to protect their crops from birds and other seed predators!

Quinoa flowers

Quinoa flowers. Image credit: Alan Cann. Used under license: CC BY-SA 2.0.

 

Quality quinoa

The high-quality reference genome for quinoa generated by Tester and colleagues is likely to be vital for allowing many exciting improvements in the future. Breeders hoping to improve the yield, ease of harvest, stress tolerance, and saponin content of quinoa can develop genetic markers to speed up breeding for these key traits, improving the productivity of quinoa varieties and enhancing future food security.

 


Read the paper in Nature: Jarvis et al., 2017. The genome of Chenopodium quinoa. Nature. DOI: 10.1038/nature21370

Thank you to Professor Mark Tester (KAUST) for providing information used in this post!