598 / 2019-04-19 20:52:20

The genetic basis of intraspecific competition in Arabidopsis thaliana

intraspecific interaction, genetics, QTL

Environmental Interactions > Environmental Interactions

In natural and agricultural environments, one of the key stresses that plants face is competition from neighbours. Plant-plant interaction is a dynamic and multiple process that involves numerous changes in morphology, physiology and reproductive success (fitness), but the extent of genetic variation in these effects remains largely unknown. Using a set of 480 Recombinant Inbred Lines from an Arabidopsis multi-parent advanced generation intercross (MAGIC), we (1) compared morphological traits and fitness with or without intra-genotypic competition and with or without nutrient stress and (2) mapped traits, and the response to competition to regions of the genome by a quantitative trait loci (QTL) approach. We found that, as expected, plants were generally smaller and produce fewer fruits, when grown with competitors. But, there was extensive genetic variation in the competitive response of the different lines. We found QTL regions strongly associated with variation in fruit number and the intensity of competition (although interactions with nutrient revealed the complexity of these effects). We also found that small plant size was associated with higher collective productivity under competition and we identified erecta as a gene that underlies this effect. Overall, we report a set of QTL regions and candidate genes related with intraspecific competition. However, there is a complex genetic basis and responses are genotypic dependent and highly influence by the environment.