Recently, the rice functional genomics innovation team of China National Rice Research Institute revealed that SBM1, a major nutrient-efficient gene selected by rice evolutionary selection, affects rice yield. This research provides excellent alleles and theoretical basis for breeding environmentally friendly rice varieties with higher yield potential and nitrogen fertilizer use efficiency. Related research results were published in”Plant Biotechnology Journal”.
In recent years, due to the continuous reduction of rice planting area and the excessive input of chemical fertilizers, new contradictions between the increase in output, resource consumption and environmental pollution have become increasingly prominent, and there is an urgent need to further tap the potential for high yield of rice. Therefore, the effective screening and identification of rice nutrient-efficient major genes and new germplasm is a necessary way to direct selection of super rice varieties through molecular design, and it is also the key to solving current contradictions.
The team used a recombination inbred line population derived from the parental 93-11 and PA64s hybrids of the two-line super hybrid rice”Liangyou Peijiu”, and a near-isogenic line derived from the indica Kasalath target chromosome fragment introduced into the background of Nipponbare. Completed the cloning of a major QTL qSBM1 on rice chromosome 1 that regulates rice biomass. The gene function verification showed that the down-regulation of the function of the SBM1 gene would lead to an increase in rice plant height, grain number per panicle, biomass and yield. Through sequence and phenotypic analysis of different types of rice germplasm materials from different environmental regions, it was found that SBM1 showed significant indica-japonica differentiation among different rice subgroups. Among them, the SBM1 type carried by the indica variety Kasalath is the most favorable genotype. The haplotype may have originated in Bangladesh at the earliest. It can exhibit high nitrogen fertilizer use efficiency and grain yield under low nitrogen, and is used in the process of rice breeding and improvement. Subject to selection, it has obvious potential for breeding applications. In addition, it was also found that SBM1 can interact with the mitogen-activated protein kinase OsMPK6, which is related to the regulation of grain traits, and gene editing technology proved that the two co-regulate biomass and grain number per ear.
The research was funded by the National Natural Science Foundation of China, the National Key R&D Program and the Zhejiang Talent Program.
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