MSH7 confers quantitative variation in pollen fertility and boosts grain yield in maize

Fertile pollen is critical for the survival, fitness and dispersal of flowering plants, and directly contributes to crop productivity. Extensive mutational screening studies have been carried out to dissect the genetic regulatory network determining pollen fertility, but we still lack fundamental knowledge about whether and how pollen fertility is controlled in natural populations. We used a genome-wide association study (GWAS) to show that ZmGEN1A and ZmMSH7, two DNA repair-related genes, confer natural variation in maize pollen fertility. Mutants defective in both genes exhibited abnormalities in meiotic or post-meiotic DNA repair, leading to reduced pollen fertility. More importantly, ZmMSH7 underwent selection during maize domestication, and its disruption resulted in a substantial increase in grain yield and protein content for both inbred and hybrid. Overall, our study describes the first systematic examination of natural genetic effects on pollen fertility in plants, providing valuable genetic resources for optimizing male fertility. Moreover, ZmMSH7 may be a potential candidate for simultaneous improvement of grain yield and quality. RNA-seq liabraries were prepared using developing maize seeds (7 DAP and 14 DAP) of zmmsh7-2 and wild-type plants