Unlocking the Potential of Grasspea for Resilient Agriculture in Drought-prone Environments (UPGRADE)

Grass pea is a pulse crop with remarkable tolerance to drought as well as flooding, making its seeds an important local food source in several tropical countries, especially Ethiopia, Sudan and Eritrea as well as India and Bangladesh. In times of weather extremes causing crop losses, grass pea often remains one of the most available foods and the cheapest source of protein, helping people survive during food shortages. The mounting challenge of climate change increases the need for crops that can be grown sustainably and withstand weather extremes. Through its 8000-year history of cultivation grass pea has been a part of human diets - from Neolithic sites in the Balkans, through the bronze-age middle east, the Roman Empire and medieval Europe until the modern day. But despite its value for food and nutritional security, grass pea carries the stigma of a potentially dangerous food. Its seeds and leaves contain a neurotoxic compound that can cause a debilitating disease known as neurolathyrism. This disease only appears in people who are malnourished and consume large amounts of grass pea over several months. Yet the fear of neurolathyrism, which has been known since antiquity, has led to grass pea being undervalued by farmers, breeders and scientists, making it an 'orphan crop'. There is no significant international trade in grass pea and too little research to develop the potential of this resilient, sustainable source of protein. Grass pea is able to fix nitrogen from the air (through symbiosis with nodulating bacteria), can efficiently use soil phosphate through its mycorrhizal associations, can penetrate into hard, heavy soil and is relatively tolerant to pests and diseases. All these characteristics make it an ideal crop for agriculture where farming inputs (fertiliser, pesticides, irrigation, etc.) are limited, as is the case in most smallholder farms in Sub-Saharan Africa. We therefore believe that improved grass pea varieties can have a significant impact beyond the millions of people who already cultivate it in Africa today and could become a crucial sustainable food source for many more.
Our project aims to remove the limitations of this crop by using the tools and resources we have already developed in our previous research to breed new varieties that are safe to consume, high-yielding, nutritious and resilient to environmental stress. We have identified new low-toxin variants with lower beta-ODAP contents than any existing varieties. In addition we have sequenced and assembled the grass pea genome and transcriptomes under stress and non-stress conditions and we are working to enable modern crop improvement methods on the back of these. Through this research partnership we have access to grass pea lines representing the global diversity of the crop and those that are locally adapted to East Africa and to expertise on smallholder agriculture and seed systems.
The UPGRADE project will build on this foundation and create a partnership to translate bioscience research advances on grass pea into new varieties with tangible benefits for smallholder farmers. Besides this, our research will generate valuable data on the performance of grass pea and the physiological role and regulation of the production of the toxin in the plant. Through a better foundational understanding, we and other researchers will be better able to direct future breeding efforts and deliver the promise of grass pea.

Grass pea (Lathyrus sativus) is the most drought-tolerant legume crop, and shows remarkable tolerance to flooding. It serves primarily as a grain crop for food use, but has multiple secondary uses as a leafy vegetable, a cover crop, green manure and fodder. Grass pea is crucial for food security in many Low and Middle Income Countries. In the Sub-Saharan Africa region, grass pea is most widely cultivated in Ethiopia, Sudan and Eritrea.

Grass pea produces a toxin, Beta-ODAP. While it is safe to consume as part of a mixed diet and is a regular food for more than 100 million people worldwide, the known risk of neurolathyrism has led to grass pea being disfavoured by many consumers and consequently by breeders. Its environmental resilience allows it to be cultivated successfully under conditions that cause the failure of other crops, making it an important 'insurance crop' for smallholder farmers.
UPGRADE will introgress novel low-ODAP and high-methionine traits into locally adapted germplasm using marker-assisted selection and characterise the performance of isogenic high- and low-ODAP lines under agricultural stress conditions. UPGRADE will trial the performance of grass pea in drought-tolerant, mixed forage systems to investigate the potential of grass pea for enhancing fodder production in water-stressed regions. UPGRADE will identify novel variation for yield-, nutrition-, and disease resistance-associated traits by TILLING and develop protocols for transformation/genome editing to allow rapid improvement of the grass pea crop in the future.

UPGRADE will co-ordinate lab- and glasshouse-based research in the UK with field studies in Ethiopia and Kenya including field sites in multiple agroecological zones. The international nature of the consortium will allow rapid integration of new developments into breeding programmes in Sub-Saharan Africa which will lead to the release of new, locally-adapted varieties within 5 years of project completion.

UPGRADE will focus on translating our previous work, using our new low-ODAP lines for the development of safe, reliable, and locally adapted grass pea varieties for East Africa. UPGRADE aims to develop new applications for grass pea for soil nutrient management and climate resilience of forage crop systems. UPGRADE will build a partnership between UK and SSA research institutions to turn scientific advances on grass pea into novel crop varieties that will benefit smallholder farmers directly. UPGRADE will underpin future improvement of this orphan crop by researchers in the UK, SSA and beyond.

UPGRADE will address directly several Sustainable Development Goals (SDGs)

Goal 2: Zero Hunger
Grass pea is a crop ideally suited to improving food production in challenging agricultural conditions. Both drought and flooding are unpredictable weather extremes that can cause severe crop losses, leading to famine. Furthermore, sudden flooding can follow a period of drought, causing losses even in crops adapted to either one of these stresses. The production of safe, high-yielding varieties of grass pea adapted to local agricultural conditions will help maintain food security during times of widespread crop failure.

As a crop that can be grown successfully with minimum inputs, grass pea is also suitable for agriculture as a side business (common for many smallholder farmers in LMICs) and during political disruptions that limit the access to farming inputs. SSA farmers often choose not to use costly inputs because of the risk of losing all to crop failure. If that risk is lessened by the resilience of grass pea, they may be more likely to invest in inputs that improve overall yield.

Due to its high protein content (28-30 % of seed dry weight) and high content of lysine, grass pea can make a significant contributions to nutritional security beyond the provision of calories alone.

Goal 12: Responsible Consumption and Production
As a deep-rooting pulse crop suited to heavy soils, the expansion of grass pea production will contribute substantially to regenerating compressed and nitrogen-poor soils for agriculture. This will make agricultural land use more sustainable and allow more depleted and marginal land to be brought into productive use, thus facilitating sustainable intensification of agriculture.

Goal 13: Climate Action
Pulses have a very low carbon footprint, as they can be grown without the addition of artificial nitrogen fertiliser and can even supplement the nitrogen needs of other crops in crop rotations or mixed stands. Pulses have the lowest CO2e impact and land-use per gram of protein of all protein-rich agricultural foodstuffs. Expanded cultivation of grass pea will intensify pulse production in marginal areas, increasing food and protein production, while minimising environmental impacts.

Goal 17: Partnership for the Goals
UPGRADE will build a partnership involving researchers engaged in fundamental science and platform development, breeders focused on variety development for Sub-Saharan Africa and seed-system specialists with experience in distributing new pulse varieties to smallholder farmers. This partnership will enable the future improvement of grass pea to be streamlined, allowing breeding of new traits developed using the TILLING platform, to be bred into locally adapted varieties using markers identified from the grass pea genome.

Scientific impacts
In addition to tangible impacts on food security and sustainability of agriculture, UPGRADE will generate data to further our understanding of metabolism. By screening isogenic high/low-ODAP genotypes under real agricultural stress conditions we will learn about the crucial genotype x environment interactions determining ODAP production. The performance of the new mutant lines under different environments will provide evidence to settle the question of the physiological role of ODAP for the plant. Metabolomic data on mutants of genes