Identifying genes that make plants 鈥渃ooperate鈥� with their neighbours rather than compete with them could enable breeders to develop more productive crops.
Natural selection usually favours 鈥渟elfish鈥� plants that beat their rivals in the competition for light, space and nutrients. But crop breeders can boost overall yield by selecting plants with traits that are helpful to nearby plants, such as shorter stems, less spread out leaves and compact roots.
During the 鈥済reen revolution鈥� of the 1950s and 60s, breeders developed dwarf cereal plants with short stems that shaded neighbouring plants less and avoided toppling over, resulting in major yield improvements unlike any observed since.
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Genetic analysis could be the key to discovering more of these cooperative traits that would enhance breeding programmes, says at the University of Zurich in Switzerland. 鈥淥ptimising the collective performance of plant groups may be achieved relatively easily, once we know how to identify cooperative traits or genes.鈥�
Wuest and his colleagues came up with a simple breeding experiment to identify how cooperative a plant鈥檚 genetic makeup is. They grew specimens of thale cress (Arabidopsis thaliana) alongside neighbours that were genetically similar or dissimilar.
By comparing how well each plant grew alongside similar or dissimilar plants, the researchers could determine which set of genes either promoted the ability to grow rapidly and competitively or the ability to grow cooperatively.
They discovered a gene with two variants, in which the less frequent 鈥� or minor 鈥� variant was strongly associated with cooperation.
Plants with this variant collectively produced 15 per cent more biomass when grown in high-density situations than those carrying the other version of the gene. This could be because plants with the minor variant didn鈥檛 invade their neighbours鈥� root zones with their own roots as much, allowing more equitable access to nutrients.
Similar experiments with crop plants may help breeders find genes that promote cooperation and improve yields.
Combining genetic techniques with breeding for cooperative traits is a promising approach, says at the University of Copenhagen in Denmark. 鈥淚f we鈥檙e going to have another breakthrough [such as the Green Revolution], this is the line we are heading in.鈥�
PLoS Biology
