Professor Ren Xifeng's team at Huazhong Agricultural University (HZAU) published a research paper titled "Unraveling the regulatory network of barley grain metabolism through the integrative analysis of multiomics and mQTL" in Nature Communications.

Using the "Huaai 11 x Huadamai 6" barley DH population as material, the study constructed a global co-expression regulatory network of barley grain development. Through this network, candidate genes regulating the biosynthesis of important metabolites such as flavonoids were identified. The study reconstructed the metabolic and regulatory network by elucidated the functions of key structural genes in the flavonoid metabolism pathway and their regulatory relationships with transcription factors.

For the first time in barley, researchers validated the protein-protein interaction between the NAC transcription factor HvNAC-1 and the MYB transcription factor HvMYB-1, proposing a new model for the regulation of barley grain flavonoid metabolism. In the early stages of grain development, the flavonoid synthesis pathway is activated, leading to the synthesis of a large amount of flavonoid monomers. In the later stages, the pathway is closed, and monomers undergo modification reactions, with HvNAC-1 and HvMYB-2 acting as "switches" in regulation.

Regulatory model of barley grain color differentiation. [Photo/news.hzau.edu.cn]

Furthermore, the team used this network to unravel a new mechanism for grain color differentiation, identifying the known gene cluster MbHF35 and two new genetic hotspots. Through genetic transformation and functional analysis of candidate genes HvMYC-1 and HvC1-1 in barley and Arabidopsis, as well as haplotype analysis of three loci, the results indicated that these three loci collectively determine barley grain color differentiation. HvC1-1 and HvMYC-1 can effectively compensate for the functional defects of HvMYB4H and HvMYC4H in the MbHF35 gene cluster, ensuring the normal expression of HvHF35 to deepen the color of barley grains.