Phenotyping stomatal closure by thermal imaging for GWAS and TWAS of water use efficiency-related genes

• DOI: 10.1093/plphys/kiab395
• Publication Date: 2021-08-14T03:54:58Z
• Authors: Charles P Pignon; Samuel B Fernandes; Ravi Valluru; Nonoy Bandillo; Roberto Lozano; Edward Buckler; Michael A Gore; Stephen P Long; Patrick J Brown; Andrew D B Leakey
• Keywords: Stomatal Conductance; Candidate gene; Water Use Efficiency; Light intensity; Genome-wide Association Study

Abstract Stomata allow CO2 uptake by leaves for photosynthetic assimilation at the cost of water vapor loss to atmosphere. The opening and closing stomata in response fluctuations light intensity regulate fluxes are essential maintaining water-use efficiency (WUE). However, a little is known about genetic basis natural variation stomatal movement, especially C4 crops. This partly because change difficult measure scale required association studies. Here, we used high-throughput thermal imaging bypass phenotyping bottleneck assess 10 traits describing conductance (gs) before, during after stepwise decrease diversity panel 659 sorghum (Sorghum bicolor) accessions. Results from significantly correlated with gas exchange measurements. gs varied substantially across population were moderately heritable (h2 up 0.72). An integrated genome-wide transcriptome-wide study identified candidate genes putatively driving traits. Of 239 unique greatest confidence, 77 putative orthologs Arabidopsis (Arabidopsis thaliana) related functions implicated WUE, including opening/closing (24 genes), stomatal/epidermal cell development (35 leaf/vasculature (12 or chlorophyll metabolism/photosynthesis (8 genes). These findings demonstrate an approach finding genotype-to-phenotype relationships challenging trait as well further investigation WUE model grass bioenergy, food, forage production.