Abstract
Abstract:
Seed dormancy (SD) and pre-harvest sprouting (PHS) impact the yield and quality of grain and hybrid seed production. Although the benefits of studying SD and seed germination (SG) during seed development have been established, research on the genetic variation and molecular regulation of SD, as well as the transition from SD to SG, remains limited. In this study, 40X BSA-QTL resequencing and linkage analysis were employed for QTL mapping of the maize vp16 mutant of PHS. Through genetic and molecular biological methods, the candidate gene was identified as Zmccr3. This gene encodes cinnamoyl-CoA reductase 3 (ccr3), which participates in the phenylalanine pathway to regulate lignin metabolism, thereby affecting SG. Based on RNA-seq of 36 samples at two stages of grain development with extreme PHS traits from three maize populations, a Weighted gene coexpression network analysis (WGCNA) related to SD and SG formation was constructed. Ten target genes and three pathways (lipid metabolism, reactive oxygen species) homeostasis under redox of electrophilic compounds, and cell wall oligosaccharide metabolism) were identified. Using WGCNA, vp16-RNA-seq, vp16-iTRAQ, and physiological and biochemical evidence, the Zmccr3 pathway was established and validated. This pathway involves Zmccr3-mediated energy supply for lipid metabolism, redox of electrophilic compounds, gibberellic acid levels or signaling regulation for endosperm weakening, and cell wall metabolism, affecting SG or SD. These findings have significant theoretical and practical implications for understanding the genetic basis of maize PHS and SD, increasing genetic resources, and improving trait genetics.