TaGS5-3A, a grain size gene selected during wheat improvement for larger kernel and yield

Area of Science:

• Plant genetics and breeding
• Molecular biology of crop development
• Agricultural science

Background:

• Grain size is a critical determinant of grain weight in cereal crops.
• The rice gene OsGS5 regulates grain size and weight by promoting cell division.
• Understanding homologous genes in wheat is crucial for improving yield.

Purpose of the Study:

• To isolate and characterize TaGS5 homoeologues in wheat.
• To investigate the role of TaGS5 in regulating grain size and weight.
• To explore the potential of TaGS5 alleles in wheat breeding.

Main Methods:

• Isolation and chromosomal mapping of TaGS5 homoeologues in wheat.
• Analysis of temporal and spatial gene expression patterns.
• Identification and functional marker development for TaGS5-3A alleles.
• Association analysis, biochemical assays, and transgenic rice studies.
• Evolutionary analysis of TaGS5-3A during wheat polyploidization.

Main Results:

• TaGS5 homoeologues were mapped to wheat chromosomes 3A, 3B, and 3D, with preferential expression in developing grains.
• The TaGS5-3A-T allele was significantly associated with larger grain size and higher thousand kernel weight compared to TaGS5-3A-G.
• TaGS5-3A-T exhibited higher enzymatic activity and led to increased grain size and weight in transgenic rice.
• Evolutionary analysis revealed strong artificial selection favoring TaGS5-3A-T in modern wheat cultivars.

Conclusions:

• TaGS5-3A acts as a positive regulator of grain size and weight in wheat.
• The favored allele, TaGS5-3A-T, has significant potential for application in high-yield wheat breeding.
• Understanding TaGS5-3A's role provides insights into cereal yield improvement strategies.