It has been predicted that agricultural water scarcity will increase in more than 80% of the world’s croplands by 2050. Improving the water use efficiency (WUE) of crops represents an important way to confront this challenge and ensure crop production. WUE is the ratio of biomass produced to units of water consumed by the crop. Although some genes have been reported to regulate WUE by manipulating the transpiration side, our knowledge about genes that regulate the biomass side of WUE remains quite limited. Govinal Badiger Bhaskara, from the University of Texas at Austin, and colleagues now report a genome-wide association study (GWAS) for WUE in Arabidopsis, identifying a set of novel genes that regulate WUE, including those affecting biomass accumulation.
Different Arabidopsis accessions exhibit varying water-use efficiency. The researchers re-analysed the integrated WUE measured through carbon isotope (δ13C) discrimination in a subset of 185 accessions reported in a previous study. GWAS was performed using the WUE of the well-watered control and drought treatments, as well as using WUE plasticity as the difference between the drought treatment and a well-watered condition. Genomic regions associated with WUE plasticity were found and were combined with stress-responsive transcriptome data to yield a list of 101 candidate genes that are likely to affect WUE plasticity.
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