TaNAC020 homoeologous genes are associated with higher thousand kernel weight and kernel length in Chinese wheat

Abstract

NAC proteins constitute one of the largest plant-specific transcription factor (TF) families and play significant roles in plant growth and development. In the present study, three TaNAC020 homoeologous genes located on chromosomes 7A, 7B, and 7D were isolated from wheat (Triticum aestivum L.). TaNAC020s were predominantly expressed in developing grains. The developed transgenic rice lines for TaNAC020-B showed higher starch density and lower amylose contents than those of the wild type (WT). Sequence polymorphism studies showed seven and eight SNPs in TaNAC020-A/B, making three and two haplotypes, respectively. No sequence polymorphism was identified in TaNAC020-D. Association analysis revealed that HAP-2 of TaNAC020-A and TaNAC020-B was the favored haplotype for higher thousand kernel weight and length. Geographic distribution and allelic frequency showed that our favored haplotype experienced strong selection in China, and likewise, diversity increased in TaNAC020s during wheat polyploidization. The results obtained in this study demonstrate that TaNAC020s positively influence starch synthesis and accumulation and are one of the key regulators of the kernel (seed) size and kernel number and have the potential for utilization in wheat breeding to improve grain yield. Molecular markers developed in this study stand instrumental in marker-assisted selection for genetic improvement and germplasm enhancement in wheat.

Molecular Network for Regulation of Seed Size in Plants

“…NAC proteins belong to one of the largest families of plant-specific transcription factors (TFs), and they play important roles in plant growth and development. TaNAC020s are mainly expressed in developing grains [ 49 ]. Transgenic rice overexpressing TaNAC020-B were found to exhibit higher starch density and lower amylose contents than WT [ 49 ].…”

“…TaNAC020s are mainly expressed in developing grains [ 49 ]. Transgenic rice overexpressing TaNAC020-B were found to exhibit higher starch density and lower amylose contents than WT [ 49 ]. In wheat, TaNAC020s positively regulated starch synthesis and accumulation and were critical regulators of grain size and number [ 49 ].…”

“…Transgenic rice overexpressing TaNAC020-B were found to exhibit higher starch density and lower amylose contents than WT [ 49 ]. In wheat, TaNAC020s positively regulated starch synthesis and accumulation and were critical regulators of grain size and number [ 49 ]. Overexpression of TaNAC100 in wheat suppresses plant height, prolongs the heading date, and promotes seed size and 1000-grain weight [ 50 ].…”