Genetics to boost sugarcane production

Scientists in Brazil are taking steps towards genetically modifying sugar cane so it produces more sucrose naturally, looking to eventually boost the productivity and economic benefits of the tropical grass.

A man stacks sugarcane at the Ver-o-Peso (Check the Weight) market in Belem.

Currently, it is common for producers to raise sucrose levels in sugar cane by applying artificial growth regulators or chemical ripeners. This inhibits flowering, which in turn prolongs harvest and milling periods.

One of these growth regulators, ethephon, is used to manage agricultural, horticultural and forestry crops around the world. It is widely used to manipulate and stimulate the maturation of sugarcane as it contains ethylene, which is released to the plant on spraying.

Ethylene, considered a ripening hormone in plants, contributes to increasing the storage of sucrose in sugar cane.

“Although we knew ethylene helps increase the amount of sugar in the cane, it was not clear how the synthesis and action of this hormone affected the maturation of the plant,” said Marcelo Menossi, professor at the University of Campinas (Unicamp) and coordinator of the project, which is supported by the Brazilian research foundation FAPESP.

To study how ethylene acts on sugarcane, the researchers sprayed ethephon and an ethylene inhibitor, aminoethoxyvinylglycine (AVG), on sugar cane before it began to mature.
sucrose accumulation.jpg

After spraying both compounds, they quantified sucrose levels in tissue samples from the leaves and stem of the cane. They did this five days after application and again 32 days later, on harvest.

Those plants treated with the ethephon ripener had 60 per cent more sucrose in the upper and middle internodes at the time of harvest, while the plants treated with the AVG inhibitor had a sucrose content that was lower by 42 per cent.

The researchers were then able to identify genes that respond to the action of ethylene during ripening of the sugar cane. They also successfully identified the genes involved in regulating sucrose metabolism, as well as how the hormone acts on sucrose accumulation sites in the plant.

Based on the findings, the team has proposed a molecular model of how ethylene interacts with other hormones.

“Knowing which genes or ripeners make it possible for the plant to increase the accumulation of sucrose will allow us to make genetic improvements in sugarcane and develop varieties that over-express these genes, without the need to apply ethylene, for example,” explained Menossi.

This research could also help with spotting the most productive sugar cane, as some varieties that do not respond well to hormones, he added. “It will be possible to identify those [varieties] that best express these genes and facilitate the ripening action.”

Taken from a newsletter by FAPESP, a SciDev.Net donor, edited by our Latin America and the Caribbean desk

 

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Rise in groundwater overuse could hit food prices

By Neena Bhandari

[SYDNEY] The increasing use of groundwater for irrigation poses a major threat to global food security and could lead to unaffordable prices of staple foods. From 2000 to 2010, the amount of non-renewable groundwater used for irrigation increased by a quarter, according to an article published in Nature on March 30. During the same period China had doubled its groundwater use.

The article finds that 11 per cent of groundwater extraction for irrigation is linked to agricultural trade.

“In some regions, for example in Central California or North-West India, there is not enough precipitation or surface water available to grow crops like maize or rice and so farmers also use water from the underground to irrigate,” the article says.

“When a country imports US maize grown with this non-renewable water, it virtually imports non-renewable groundwater.”

Carole Dalin,  Institute for Sustainable Resources at University College, London

The article focused on cases where underground reservoirs or aquifers, are overused. “When a country imports US maize grown with this non-renewable water, it virtually imports non-renewable groundwater,” Carole Dalin, lead author and senior research fellow at the Institute for Sustainable Resources at University College, London, tells SciDev.Net.

Crops such as rice, wheat, cotton, maize, sugar crops and soybeans are most reliant on this unsustainable water use, according to the article. It lists countries in the Middle East and North Africa as well as China, India, Mexico, Pakistan and the US as most at risk.

“Pakistan and India have been locally most affected due to groundwater depletion and exporting agricultural products grown with non-sustainable groundwater. Iran is both exporting and importing and The Philippines is importing from Pakistan, which is non-sustainable. China is importing a lot from India. Japan and Indonesia are importing, mainly from the US,” says Yoshihide Wada, co-author of the report and deputy director of the International Institute for Applied Systems Analysis’s Water Programme, Laxenburg, Austria.

Agriculture is the leading user of groundwater, accounting for more than 80 to 90 per cent of withdrawals in irrigation-intense countries like India, Pakistan and Iran, according to the report.

The researchers say efforts to improve water use efficiency and develop monitoring and regulation need to be prioritised. Governments must invest in better irrigation infrastructure such as sprinkler irrigation and introduce new cultivar or crop rotation to help producers minimise water use.

Wada suggests creating awareness by putting water labels, along the lines of food labels, “showing how much water is used domestically and internationally in produce and whether these water amounts are from sustainable or non-sustainable sources”.

Andrew Western, professor of hydrology and water resources at the University of Melbourne’s School of Engineering, suggests enforceable water entitlement systems and caps on extraction. “In recent decades, water reform in Australia has led to water having a clear economic value made explicit by a water market. This has enabled shifts in water use to cope with short-term climate fluctuations and has also driven a trend of increasing water productivity,” he says.

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

 

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

Creole maize reveals adaptation secrets

By Lucina Melesio

[MEXICO CITY] An international team of scientists identified a hundred genes that influence adaptation to the latitude, altitude, growing season and flowering time of nearly 4,500 native maize varieties in Mexico and in almost all Latin American and Caribbean countries.

Creole — or native — varieties of maize are derived from improvements made over thousands of years by local farmers, and contain genes that help them adapt to different environments.

“We are now using this analysis to find other genes that are of vital importance to breeders, such as those resistant to extreme heat, frost or drought — environmental conditions associated with climate change and that could affect maize production.”

Sarah Hearne, CIMMYT

“Latin American breeders will be able to use these results to identify native varieties that could contribute to improved adaptation”, Edward Buckler, a Cornell University researcher and co-author of the study published in Nature Genetics (February 6), told SciDev.Net.

The information on the genetic markers described in the study will be available online, said Sarah Hearne, a researcher at the International Maize and Wheat Improvement Center (CIMMYT) and co-author of the study. “Meanwhile, any breeder can contact us to request information”, she said.

“We are now using this analysis to find other genes that are of vital importance to breeders, such as those resistant to extreme heat, frost or drought — environmental conditions associated with climate change and that could affect maize production”, Hearne said.

Maize ears from CIMMYT’s collection, showing a wide variety of colors and shapes. CIMMYT’s germplasm bank contains about 28,000 unique samples of cultivated maize and its wild relatives, teosinte and Tripsacum. These include about 26,000 samples of farmer landraces—traditional, locally-adapted varieties that are rich in diversity. The bank both conserves this diversity and makes it available as a resource for breeding.
Photo credit: Xochiquetzal Fonseca/CIMMYT.

Studying native maize varieties is extremely difficult because of their genetic variation. Although domesticated, they are wilder than commercial varieties.

For this study, the researchers cultivated hybrid creole varieties in various environments in Latin America and identified regions of the genome that control growth rates. They looked into where the varieties came from and what genetic features contributed to their growth in that environment.

 In comments to SciDev.Net, James Holland, a researcher at North Carolina State University, Jeffrey Ross-Ibarra, a researcher at the University of California Davis, and Rodomiro Ortiz, a researcher at the Swedish University of Agricultural Sciences — who did not participate in the study — commended the magnitude of the study and the original method developed by the researchers to access the rich set of genetic information about native maize varieties.

Hearne added that the research team has initiated a “pre-breeding” programme with a small group of breeders in Mexico. As part of that programme, CIMMYT delivers to breeders materials from its germplasm bank of Creole maize; it also provides molecular information the breeders can use to generate new varieties.

This piece was produced by SciDev.Net’s Latin America and Carribean edition.

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

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.

The future of phenotyping

This week’s post was written by Dr Kasra Sabermanesh, Rothamsted Research.

I am a post-doctoral research scientist within Rothamsted Research’s BBSRC-funded 20:20 Wheat® program, which aims to provide the knowledge base and tools to increase the UK wheat yield potential from 8.4 to 20 tons of wheat per hectare within the next 20 years. Field phenotyping is one component of this program and facilitates the non-destructive monitoring of field-grown crops. Traditional methods of field phenotyping require huge human effort, which consequently limits the accuracy, frequency, and number of different measurements that can be taken at one time. Fortunately, Rothamsted has an exciting solution to this problem.

The Field Scanalyzer

Kasra Sabermanesh

Dr Kasra Sabermanesh shows off the Field Scanalyzer. Image credit: Rothamsted Research

Our field phenotyping platform, the Field Scanalyzer (constructed by LemnaTec GmbH and being further developed by ourselves), supports a motorized measuring platform with multiple sensors that can be accurately positioned anywhere within a dedicated field. The sensor array comprises a high-definition RGB camera, two hyperspectral cameras, a thermal infrared camera, a system for imaging chlorophyll fluorescence and twin scanning lasers for 3D information capture. Together, these sensors generate a wealth of data about crop growth, architecture, performance, and health. The Field Scanalyzer operates autonomously and in high-throughput, meaning it can take a lot of non-destructive measurements without human supervision, throughout the crops lifecycle, with high-accuracy and reproducibility. (You can read more about the Field Scanalyzer in our recent paper: http://www.publish.csiro.au/FP/pdf/FP16163).

We are currently using the Field Scanalyzer to identify new characteristics of crops that relate to performance, as well as identifying new genetic diversity for existing traits. Outputs from either of these research components can be delivered to breeders. We are screening approximately 400 wheat varieties, but also imaging some oilseed rape and oat plants.

Rothamsted Research

The scanalyzer. Image credit: Rothamsted Research

The big data problem

The Field Scanalyzer at Rothamsted is a world first, so we initially had to develop all the necessary image acquisition protocols and image processing tools, in order to exploit its full capabilities. A number of image processing tools are available; however, they are not suitable for field-grown crops, as they were not developed for complex canopies consisting of hundreds of plants in highly dynamic ambient conditions. The platform can generate up to 100 TB data with a year’s continuous operation (using all of the sensors). That’s why I work with two other post-docs to develop robust computer vision tools to automate the way we extracting quantitative image datasets. We are also validating the accuracy of the values extracted from our images by comparing them with measurements obtained manually.

Approximately 1.5 years have passed since we first began operating the Field Scanalyzer, and we have now optimized all of our image acquisition protocols and have collected a full seasonal dataset. With the good quality images stored in our database, we have developed some robust tools to automatically extract the information about some key growth stages (ear emergence and flowering), as well as quantifying height and the number of some plant organs. We are still just scraping the surface though, and have a list of traits for which we want to develop computer vision tools, in order to automatically analyze them.

Take to the skies: Drones for data collection

Some of my colleagues work with drones (UAVs) to capture information about crop height, plant density (Normalized Difference Vegetation Index), and canopy temperature from large-scale field trials containing 5000 plots. They also fly the UAVs over our Field Scanalyzer site, so we can compare data collected from the higher flying UAV with those collected from the Field Scanalyzer at close proximity. The way we see it, UAVs can image large fields in a very short time (15 min), so if we notice something interesting using the UAV at the large plot-scale, we can put the material under the Field Scanalyzer for high-resolution phenotyping. On the other hand, with the Field Scanalyzer, once we gain a better understanding of which trait/s we need to focus on, when we should be looking at them, and exactly which sensor/s are required to quantify the trait, we can deploy drones with the necessary sensors (once the sensors are portable enough) to collect this information at field-scale and at the appropriate time.

Drones at Rothamsted

Taking to the skies: Drones are used for large-scale phenotyping at Rothamsted. Credit: Rothamsted Research.

The future of phenotyping

I envision that the future of phenotyping technology will focus on reducing the cost and size of cameras/sensors, ultimately increasing their portability and accessibility. This will result in more sophisticated cameras being attached to UAVs (as many of sensors we currently use far out-weigh a UAV’s payload). Parallel to this, research efforts are focusing on developing image processing systems that efficiently extract quantitative information about the crops from acquired images. Together, phenotyping systems such as low-flying UAVs that generate easily interpreted data outputs could be developed, which may be more widely adopted by breeders and farmers to get a deeper insight into their crop’s health and performance.

Break down barriers between seed banks and field study

By Marie Haga , Ann Tutwiler

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.

The effective and efficient conservation of agricultural biodiversity — the biodiversity that’s important for providing the food we eat — is vital to meeting the global challenges of food and nutritional security for an expanding world population under the threat of climate change, and growing pressures on land and water.

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.

First steps

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

 

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

Genome editing: an introduction to CRISPR/Cas9

Damiano Martignago

Dr Damiano Martignago, Rothamsted Research

This week’s blog post was written by Dr Damiano Martignago, a genome editing specialist at Rothamsted Research.

 

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.

CRISPR/Cas9

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.

Wheat powdery mildew

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.

 

Using CRISPR, scientists from the Chinese Academy of Sciences produced a wheat variety resistant to powdery mildew, one of the major diseases in wheat. Similarly, another Chinese research group exploited CRISPR to produce a rice line with enhanced rice blast resistance that will help to reduce the amount of fungicides used in rice farming. CRISPR/Cas9 has also been already applied to maize, tomato, potato, orange, lettuce, soybean and other legumes.

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.

Cassava brown streak disease

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 Cellectis edited 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.

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