The natural genetic basis of cooperation in Arabidopsis: implications for crop improvement

How will the UK increase its future agricultural productivity?

One of the major successes in agricultural production involved the artificial creation of dwarfed plants. On account of their small size, these plants did poorly against taller competitors. When grown together, however, dwarfed plants provided a major boost to crop productivity. This success story is sometimes told as 'reversal' of natural selection's work to produce tall and robust competitors. On the other hand, evolutionary biologists understand that natural selection will sometimes favour 'weak' competitors. This can occur when neighbours are genetically related (e.g., siblings), so that being nice to a neighbour means that you pass your genes on, albeit indirectly. My work is based on the idea that plants in nature often grow with relatives, and so these plants may have many unknown traits that benefit neighbours and promote group productivity. At the University of Oxford, I will search through many different variants of a model plant species (Arabidopsis thaliana, a relative of cabbage and mustard), aiming to discover these cooperative plant traits and their genetic basis. After finding the most cooperative types, I will determine how productive these natural variants are relative to the dwarfed plants currently used in agriculture. As the UK's need for sustainable agriculture grows, I want to know if Nature's work can be exploited to help meet the demand.

Studying the genetic basis of plant adaptation can uncover natural alleles for future crop improvement. This is particularly true of 'social' adaptation, or how plants adapt to grow and compete with their neighbours. Evolutionary biology predicts that if plants grow with genetically related neighbours (e.g., siblings), then natural selection can favour cooperation, or reduced competitiveness over resources. Furthermore, because reduced competitiveness should free up resources for reproduction, cooperation can promote group productivity (e.g., crop yield); indeed, this is one way of interpreting the success of agriculture's green revolution. My proposed research, focussed on the model plant Arabidopsis thaliana, is based on the idea that wild A. thaliana plants often grow with relatives, and so their genomes may contain many unknown genes that benefit neighbours and promote group productivity. To address this, I will exploit the Arabidopsis MAGIC inbred lines--a new genetic resource that captures much of the natural variation in the species. Specifically, I will: (1) perform a QTL analysis to map the genetic basis of plants' competitiveness towards related neighbours; (2) use RNA-Seq to test whether the expression of cooperative traits depends on the detection of related neighbours; and (3) determine how the group productivity of naturally cooperative genotypes compares with that of 'green revolution' genotypes. My work will address fundamental questions about the genetic basis of plant adaptation to the social environment, and it will also have practical implications for crop improvement. As the need for sustainable agriculture grows, I want to know if nature's work can be exploited to help meet the demand.

Who will benefit from this research?

-- plant breeders and agronomists working in research and industry related to food crops
-- plant breeders and agronomists working in research and industry related to energy crops
-- the general public

How will they benefit from this research?

My work will identify candidate genes associated with reduced competitiveness toward genetically similar neighbours. This reduced competitiveness will often lead to higher fruit and seed production in food crops. Hence, plant breeders and agronomists in the food industry may eventually use my results to select for or design cultivars with higher collective yield (realistically, in the next ten years). This has the potential to boost the UK's agricultural productivity without increasing the use of chemicals or expanding agricultural land use. This will benefit the health of UK society and will contribute to the protection of the UK's natural biodiversity.

My research may also help to boost the productivity of energy crops. In this case, the goal is to encourage plants to allocate more energy to competitiveness (e.g. stem biomass) and less to reproduction. Social biology suggests that increased competitiveness can be promoted by encouraging interactions among individuals who are not genetically related. Increasing the productivity of energy crops may ultimately contribute to reductions in the UK's production of greenhouse gasses.

Finally, my work will be of general interest to the public. They will benefit by learning about how evolution has shaped the productivity of plants in nature and what this says about the possibilities for further improvements in agriculture. This will contribute to UK culture by encouraging public interest in basic science and its potential practical benefits.