BREAD - ABRDC: A reverse genetics platform to characterize adaptations to drought and improved nutrient density of chickpea.
Chickpea (Cicer arietinum L.) is the second most important food legume worldwide. Green seeded chickpea and vegetable chickpea is a plant-based protein diet having good nutritive value. Higher nutrient density for carotenoids such as beta-carotene that are observed in the green-seeded chickpea could contribute to improving the nutritional status of consumers.
Incorporation of the functional stay-green trait into currently grown cultivars has the potential to narrow down the yield and/or nutrient gap that predominantly occurs on small-scale farms in the semiarid tropical agricultural systems of the developing world. Lengthening the shelf-life of vegetable chickpea from incorporating the ‘stay green’ trait would also benefit a range of value chain actors including small-scale farmers, local processors and retailers that typify the chickpea production value chain.
Chickpea is produced predominantly in arid and semi-arid agro-ecologies where drought is a major constraint that typically reduces yields by over half. Production statistics from the FAO show that chickpea is the primary source of plant protein in the diets of approximately 15% of the world’s population, predominantly in South Asia and East Africa where plant-based diets are common (FAOSTAT, 2014). In addition to local consumption as food, this crop is emerging as a cash-crop for export markets in countries of east and southern Africa. In cropping systems chickpea also improves soil fertility from its capacity for symbiotic nitrogen fixation. Two draft genome sequences for chickpea are available with additional whole genome re-sequencing projects currently underway. Despite these burgeoning sequence data, tools and understanding of how to link sequence variation with plant function are lacking. We propose to (A) develop a fast neutron saturation mutagenized population of chickpea as a reverse genetics tool for understanding gene function at varying levels of plant organization. We have recently observed that among green-seeded chickpea (a rare morpho-form with green cotyledons and seed coats), some genotypes also exhibit a ‘stay-green’ phenotype wherein many plant organs including leaves and pods exhibit delayed-age senescence. Such a delayed age senescence phenotype might be linked to elevated levels of photosynthetic pigments and carotenoids since a green-seeded chickpea cultivar was shown to have elevated beta-carotene at levels that are similar to the first generation of golden rice.
Therefore we also propose to:
(B) investigate the putative trade-offs of delayed-age senescence on plant productivity under water limitation (drought);
(C) characterize the impacts of green-seededness on carotenoid levels over stages of seed ripening relevant to vegetable (fresh) and mature (dry) seed markets;
(D) use the reverse genetics platform to characterize chickpea orthologs of genes related to delayed age senescence; and,
(E) determine the molecular genetic basis of green-seededness and delayed age senescence in chickpea from whole genome sequencing and molecular genetic analysis of purpose-built populations. Together these activities would improve our understanding of the molecular basis of physiological mechanisms that underlie the delayed age senescence phenotype. Furthermore, the genotypes, sequence data and understanding of delayed-age senescence phenotype up to the agronomy context should serve as a knowledge-base for crop improvement.
Within the project we will train post-doctoral scholars (at FIU & UCD) and two graduate students in India (jointly by SKUAST & ICRISAT), and provide training opportunities in research for undergraduate students at UCD and FIU. By bringing together molecular genetics/genomics with crop physiology and applied breeding the project has potential for cross-disciplinary synergies and it provides a rich training environment for students and post-docs. Our project participants derive from an institutional framework that spans academic institutions in the US and India and a research-for development global organization, strengthening linkages among these disparate organizations.
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.