Genetic control of photoprotection and photosystem II operating efficiency in plants

Abstract

Summary Photoprotection against excess light via nonphotochemical quenching (NPQ) is indispensable for plant survival. However, slow NPQ relaxation under low light conditions can decrease yield of field‐grown crops up to 40%. Using semi‐high‐throughput assay, we quantified the kinetics of NPQ and photosystem II operating efficiency (ΦPSII) in a replicated field trial of more than 700 maize (Zea mays) genotypes across 2 yr. Parametrized kinetics data were used to conduct genome‐wide association studies. For six candidate genes involved in NPQ and ΦPSII kinetics in maize the loss of function alleles of orthologous genes in Arabidopsis (Arabidopsis thaliana) were characterized: two thioredoxin genes, and genes encoding a transporter in the chloroplast envelope, an initiator of chloroplast movement, a putative regulator of cell elongation and stomatal patterning, and a protein involved in plant energy homeostasis. Since maize and Arabidopsis are distantly related, we propose that genes involved in photoprotection and PSII function are conserved across vascular plants. The genes and naturally occurring functional alleles identified here considerably expand the toolbox to achieving a sustainable increase in crop productivity.

Comparative GWAS identifies a role for Mendel’s green pea gene in the nonphotochemical quenching kinetics of sorghum, maize, and arabidopsis

“…The second most consistently identified signal was located at position 56,606,003 on sorghum chromosome 4, approximately 500 kb from the sorghum ortholog of Zm00001d017171 (Sobic.004G210500), a maize gene identified in a GWAS of NPQ kinetic traits. Both Sobic.004G210500 and Zm00001d017171 are orthologous to OUTER ENVELOPE PROTEIN 37 ( OEP37 , At2g43950), an A. thaliana gene encoding a chloroplast-localized ion membrane channel protein, a null allele of which shows altered NPQ kinetics (Sahay et al . 2023).…”

“…2017; Rungrat et al . 2019; Sahay et al . 2023), the closest signal to the sorghum PSBS gene (Sobic.003G370000) was slightly more than 1 Mb away and modestly below our RMIP threshold for significance (Supplemental Table S1).…”

“…Black dots indicate the LD of SNPs within this mapping interval relative to Chr02:65,879,368. B) RMIP results for a reanalysis of published trait data from 746 maize genotypes from the Wisconsin Diversity panel grown in Lincoln, Nebraska, in the summer of 2020 (Sahay et al . 2023) using new higher density genetic markers from resequencing (Grzybowski et al .…”

“…We reanalyzed previously published maize NPQ kinetics data (Sahay et al . 2023) using a recently published high-density marker set (Grzybowski et al .…”

“…2022), a drought-tolerant and nitrogen-use-efficient relative of maize that is widely grown as a staple crop in Subsaharan Africa and South Asia. We identified several significant NPQ trait-associated loci including the sorghum ortholog of a gene previously reported in maize and A. thaliana (Sahay et al . 2023) and signal from sorghum and maize orthologs of NON-YELLOWING 1 (NYE1) .…”