TaGeBPL-4B, a novel gene that regulates grain number per spike in wheat
image: TaGeBPL-4B, a novel gene regulates grain number per spike in wheat
Credit: Dr. Sishen Li
Wheat is one of the most important crops globally, providing a major source of energy for human consumption. Hence, improving yield potential is an urgent objective in wheat genetic improvement.
Grain number per spike (GNS) is one of the three component factors for grain yield and a high-priority target for molecular breeding. Wheat has a very large and highly repetitive genome. Efficient cloning of wheat genes using the traditional map-based cloning method is challenging.
To address this, Professor Sishen Li from Shandong Agricultural University, China, along with his team, conducted a study to identify and confirm a candidate gene for GNS, and investigate its molecular mechanisms. The study was published online on July 14, 2026, in The Crop Journal.
Using QTL mapping in a recombinant inbred line (RIL) population and GWAS in an association panel of 272 wheat varieties based on RNA-seq resequencing, the team identified TraesCS4B02G044100, annotated as a glabrous enhancer-binding protein-like gene (TaGeBPL-4B), as the candidate gene for GNS. CRISPR/Cas9 knockout and overexpression experiments further confirmed that TaGeBPL-4B positively regulates GNS by modulating wheat spike development.
“Combining QTL mapping with GWAS based on physical positions of unigenes is an efficient strategy for gene cloning in wheat,” explains Li. “This approach has helped our group clone a series of yield-related genes in recent years, and TaGeBPL-4B is an important achievement.”
Notably, the GeBP family is plant-specific transcription factors that exhibit broad functions, and their function for GNS and spike development in wheat remained unknown. “Through integrated RNA-seq and DAP-seq analyses and Y1H, Dual-Luc and EMSA assays, we found that TaGeBPL-4B binds directly to the promoter of TaAAP-5B and activates its transcription.,” adds Li.
Further, the knockout lines of TaGeBPL-4B showed reduced free amino acid contents in booting-stage spikes, while the overexpression lines accumulated higher levels of the amino acid.
“We identified TaGeBPL-4B as a positive regulator of GNS in wheat and showed that it directly targets and activates the TaAAP-5B gene, which possibly influences spike development and GNS by modulating amino acid contents,” adds co-corresponding author Prof. Yanrong An.
The team's findings are also of practical importance in wheat breeding programs. The RNA-seq data of 272 wheat varieties revealed two haplotypes of TaGeBPL-4B. The favorable haplotype, Hap 2, conferred significantly higher GNS without a reduction in 1000-grain weight (TGW).
“By consciously selecting the Hap 2 haplotype using molecular marker, breeders can increase GNS without compromising TGW,” says co-corresponding author Prof. Ying Guo. “For global food security, this represents a novel and deployable genetic tool that can enhance yield potential.”
Author Contact:
Dr. Sishen Li
E-mail address:guoying729@126.com
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