Integrative multi-omics analysis uncovers the regulatory network of wheat grain development during grain filling

Wheat grain development is the core biological process that determines the formation of grain yield and quality. However, as a heterohexaploid crop, wheat has not been systematically analyzed for its molecular regulatory network governing grain development.

In this study, the wheat cultivar 'Dianmai 24' was used as the experimental material to identify the phenotypic characteristics of grains at three key grain filling stages, namely 7 days (d), 14 d, and 21 d after anthesis, and to integrate transcriptomic, non-targeted metabolomic, and proteomic analyses.

Phenotypic analysis showed that there were significant differences in grain width and biomass among the three stages, which exhibited the typical growth characteristics during the grain filling period. A total of 2665 metabolites were identified in the metabolomic analysis, among which flavonoids, amino acids and their derivatives, and lipid metabolites were the main differential metabolic components across different developmental stages. Transcriptomic analysis yielded a total of 85.13 Gb of clean data. A total of 10,445, 16,306, and 8,437 differentially expressed genes (DEGs) were screened out in the three comparison groups, which were significantly enriched in metabolic pathways, photosynthesis-antenna proteins, biosynthesis of secondary metabolites, starch and sucrose metabolism, and carbon metabolism. A total of 17,729 proteins were identified by proteomic analysis, among which α-amylase/trypsin inhibitor CM3, β-amylase, and globulin-3A accumulated continuously across the three stages, and these proteins may play a core role in the process of grain development.

Through multi-omics analysis, the α-linolenic acid metabolic pathway was identified as the core regulatory pathway, and 15 key genes, 17 core proteins, and 11 characteristic metabolites were screened to participate in the molecular regulatory network of grain filling. This study systematically analyzed the molecular regulatory mechanism of the wheat grain filling stage and provided important candidate genes and metabolic targets for the breeding of high-yield and high-quality wheat.