Genetic biofortification of carotenoid content of grain legumes for novel market types as high-value fresh vegetables and in processed foods
Dr. R. Varma Penmetsa (PI/PD), Assoc. Prof. Researcher, Dept. of Plant Scs, Univ. of Calif.-Davis.
Dr. Paul Gepts, (CoPI), Distinguished Professor, Dept. of Plant Sciences, Univ. of California-Davis.
Dr. Jana Kholova (CoPI), Senior Scientist, Crop Physiology, ICRISAT-India.
Dr. Eric von Rettberg (CoPI), Associate Professor, Dept. of Plant & Soil Scs, Univ. of Vermont.
Dr. George Vandemark (Collaborator), Research Geneticist, USDA-ARS, & Washington St. Univ.
Grain legumes chickpea (garbanzo bean), lima bean, common (french or snap bean) bean and cowpea (black-eyed pea or southern pea) are legumes that are sources of biologically fixed nitrogen, therefore, alleviating needs for N-fertilization in cropping systems. Despite legumes are considered nutrient-dense food crops there is a scope for their productivity and nutrient density improvement using yet-untapped genetic resources. Improvements to quantity and quality of production would ensure food supply sustainability, raise and secure incomes of value chain players, and enhance the nutritional status of the consuming human population.
A rare form of green-seeded legumes variants exist and these are usually considered as a specific category of stay-green phenotypes. Recent unpublished results in chickpea and lentil, and prior work in common bean and garden pea suggest, indeed, that green-seeded phenotype is underlined by the loss-of-function of orthologs of stay-green protein (Stgr1). This defective Stgr1 protein causes disruption of chlorophyll catabolism in plant shoot organs which is associated with higher levels of carotenoids. Using candidate gene and positional cloning we will identify the genes for green-seediness in lima bean and cowpea, and develop molecular markers to enable marker-assisted breeding. We will investigate the levels of the human nutrition-relevant seed constituents (carotenoids and protein) in grain and leaf tissues in all four-grain legumes, as their elevated levels are suggested by the molecular function of the stay-green protein. We will evaluate the agronomic parameters as well as study detailed physiological functions of normal vs green-seeded variants in a state-of-the-art phenotyping facility. These phenomic studies are carefully designed to inform breeding programs whether any agronomically important tradeoffs are associated with green-seeded phenotype across the range of environmental conditions. Outputs from this integrated project will lay the foundation for the deployment of novel genetic technologies to develop a new generation of genetically fortified grain legume cultivars that are suited to both a fresh vegetable and dry seed markets.
Our specific objectives are to:
1. Develop DNA markers for chickpea stay-green ortholog and conduct marker-assisted introgression breeding (MAIB) for fresh vegetable and dry seed markets in California and Washington.
2. Identify the molecular-genetic basis of green-seediness in lima bean and cowpea using candidate gene or positional cloning with RADseq genomics, and develop molecular markers for MAIB.
3. Characterize green-seeded variants for agronomic performance; profile selected seed nutritional components relevant to human health; investigate which physiological processes are linked to stay-green protein and its consequences for the range of SAT production environments.
4. Develop an educational module for high-school curricula using genetic stocks developed in the project to introduce concepts in genetics and physiology.
For us gems means GEMS, or G*E*M*S (genotype by environment by management by society) interactions, i.e. the fact that crop yields results from complex biophysical interactions while acceptance depends on farmer/consumer preferences. This complexity becomes an opportunity when it is cracked into components that can be analysed, understood, predicted, and then used to prioritise research investments to maximise return. This is what we do, and this is when GEMS become gems!
For us gems means GEMS, or G*E*M*S (genotype by environment by management by society) interactions, i.e. the fact that crop yields results from complex biophysical interactions while acceptance depends on farmer/consumer preferences. This complexity becomes an opportunity when it is cracked into components that can be analyzed, understood, predicted, and then used to prioritize research investments to maximise return. This is what we do, and this is when GEMS become gems!
A crop performs in different ways in different sites, years and agronomic managements. These are called genotype-by-environment-by management(G*E*M) interactions, and they are a main challenge for breeders and agronomists. There is one more layer of interaction, even more complex: the society (S). Farmers and consumers have different desires, needs, expectations, and a cultivar that fits one may not fit the other (G*E*M*S interactions). The puzzle is complex and challenging but if its components are understood, specific interventions can be undertaken.For instance, breeding for a particular genotype (G, with particular physiological characteristics), for a particular environment (E, with a particular kind of drought pattern that requires a specific adaptive trait), in a particular management practice (M, for instance a sowing density, or a N fertilizer treatment), and targeted to particular farmer/consumer (S, for instance a genotype that produces a lot of rich stover for cattle ranchers) is the need of the hour.