Natural variation in ZmGRF10 regulates tolerance to phosphate deficiency in maize by modulating phosphorus remobilization

Abstract

Phosphorus is a limiting factor in agriculture due to restricted availability in soil and low utilization efficiency of crops. The identification of superior haplotypes of key genes responsible for low-phosphate (Pi) tolerance and their natural variation is important for molecular breeding. In this study, we conducted genome-wide association studies on low-phosphate tolerance coefficients using 152 maize inbred lines, and identified a significant association between SNPs on chromosome 7 and a low-phosphate tolerance coefficient. ZmGRF10 was identified as a candidate gene involved in adaptation of maize to Pi starvation. Expression of ZmGRF10 is induced by Pi starvation. A mutation in ZmGRF10 alleviated Pi starvation stress. RNA-seq analyses revealed significant upregulation of genes encoding various phosphatases in the zmgrf10-1 mutant, suggesting that ZmGRF10 negatively regulates expression of these genes, thereby affecting low-Pi tolerance by suppressing phosphorus remobilization. A superior haplotype with variations in the promoter region exhibited lower transcription activity of ZmGRF10. Our study unveiled a novel gene contributing to tolerance to low-Pi availability with potential to benefit molecular breeding for high Pi utilization.