Spike traits are essential morphological structures that play a pivotal role in crop yield, making them a subject of intense research interest. The genetic relationship between grain characteristics and other spike traits is of utmost importance as it governs the allocation of assimilates, which are the products of plant photosynthesis. This allocation directly impacts crop yield. Despite wheat's significance as a global cereal crop, research on assimilate allocation has been relatively limited, and the underlying genetic mechanisms remain unclear. Hence, it is crucial to identify the regulatory machinery of assimilate allocation between wheat grains and other spike traits. Such findings hold paramount significance for enhancing the yield of wheat and other crops.
On August 28th, 2023, a collaborative research utilized a mapping population comprising 306 wheat accesions, representing global genetic diversity. The researchers also employed 40 million high-quality SNP data to conduct genetic analyses of wheat spike traits.
This comprehensive study involving GUO Zifeng’s group from the Institute of Botany, LU Fei’s group from the Institute of Genetics and Developmental Biology at the Chinese Academy of Sciences, MA Youzhi’s group and HAO Yuanfeng’s group from Crop Science Research Institute at the Chinese Academy of Agricultural Sciences, published new research entitled "A high-resolution genotype-phenotype map identifies TaSPL17 as a regulator of grain number and size in wheat" in the journal Genome Biology.
The study performed a genome-wide association analysis of 27 spike and grain-related traits, successfully identifying 590 associated genomic regions. Notably, 90% of these regions were newly discovered, representing valuable target loci for future spike trait dissection. The analysis of assimilate allocation traits within spikes revealed the presence of strong major-effect peaks overlapping with peaks of yield traits, as well as associated regions where yield traits were not previously identified.
The researchers leveraged high-density SNPs to detect signals related to genes or in close proximity to candidate genes. They identified TaSPL17 as a candidate gene responsible for regulating assimilate allocation. Further investigations involving mutagenesis and overexpression experiments confirmed that TaSPL17 controls grain size and quantity by regulating the development of spikelets and florets, ultimately leading to a substantial increase in grain yield. Subsequent haplotype analysis revealed distinct geographical distribution differences for TaSPL17, influenced by domestication and breeding selection. Particularly, the Hap-A2 haplotype was predominantly found in Chinese varieties; however, its prevalence has gradually decreased in modern wheat varieties due to reduced utilization in Chinese wheat breeding programs. Nevertheless, Hap-A2 holds significant potential for increasing wheat yield and remains an important target for future research.
This study has successfully established a high-density genotype-phenotype map specifically for wheat spike traits, providing a valuable resource for rapidly detecting and evaluating candidate genes associated with wheat spike traits. Three co-first authors include Yangyang Liu from Zifeng Guo’s group, Jun Chen from Crop Science Research Institute of the Chinese Academy of Agricultural Sciences, and Changbin Yin from Fei Lu’s group. The funding sources include the Chinese Academy of Sciences Strategic Priority Research Program, the Agricultural Science and Technology Innovation Program, the National Key Research and Development Program, the National Natural Science Foundation of China, and the "Leaders in Innovation" project from the Yazhou Bay Seed Laboratory in Hainan.
Genotype-Phenotype Association Map of 27 Spike Traits (Image by IGDB)
Contact:
LU Fei
Institute of Genetics and Developmental Biology, Chinese Academy of Sciences
CAS
中文
Genotype-Phenotype Association Map of 27 Spike Traits (Image by IGDB)Contact:LU FeiInstitute of Genetics and Developmental Biology, Chinese Academy of SciencesEmail: flu@genetics.ac.cn