Non-random association of alleles in the nucleus and cytoplasmic organelles confer adaptive value of clock and growth plasticity in barley populations

In plants, the role of chloroplasts and mitochondria (plasmotype) in controlling circadian clock plasticity and overall plant robustness has not been elucidated. We investigate the fitness and circadian clock variation in the wild barley (Hordeum vulgare ssp. spontaneum) collection1 and in derived interspecific populations. Our goal is to better understand a major crop`s evolution and possible utilization of naturally-occurring variations for breeding and biotechnology. Our studies identified drivers of the clock (DOC) loci that control the loss of clock plasticity between wild and cultivated populations; these loci also show the signature of selection in the genome2. In the wild populations, we identified and experimentally validated key DOCs, including the chloroplast in which alleles of the rpoC1, a member of the RNA polymerase complex, are modulating the clock plasticity in barley3. Furthermore, population analysis shows a non-random association of alleles for chloroplastic rpoC1 and nuclear DOC loci, thereby indicating the signature of selection for clock plasticity before domestication. The pleiotropic effects of the DOC on plant fitness in the field, including that of the plasmotype, prompt us to develop advanced mapping populations for pre-breeding. I will present the modelling for genetic basis of plasticity and epistatic interaction in first built cytonuclear multiparent population (CMPP), which captures the segregation of ten wild organelles and nuclear genomes in the background of an elite cultivar. Finally, I will present how we apply genome editing tools to recombine alleles for fine-mapping and identification of causal variation underlying adaptation in changing environments4