稲の胚形成欠損性状を制御する重要遺伝子OsBZR4を同定(Scientists Identify Key Gene OsBZR4 Regulating Embryoless Rice Traits with Agricultural Potential)

2025-07-30 中国科学院(CAS)

中国科学院東北地理与農業生態研究所のBU Qingyun教授らは、イネの胚欠損変異体eml1の原因遺伝子OsBZR4を特定し、その分子メカニズムを解明した。OsBZR4の変異は複数の品種で60~100%の高率で胚を欠く種子を引き起こし、scutellumと胚乳の境界で活性化されることでYUC4とPIN5bの発現を抑制し、オーキシンの濃度と分布を制御する。さらに、高温下ではOsPIL13がYUC4を促進し胚欠損率が上昇することが判明。変異型を高性能品種に導入すると、精米歩合と貯蔵性が向上した。この知見は高温感受性を活かした新たな米育種への応用が期待される。

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OsBZR4はイネの温度依存性胚発生を調節する OsBZR4 regulates temperature-dependent embryogenesis in rice

Zhenyu Wang,Min Xu,Yingxiang Liu,Xiaoming Zheng,Zhipeng Hong,Mingliang He,Xin Jin,Jiaqi Tang,Xiufeng Li,Xiaojie Tian,Qian Qian & Qingyun Bu
Nature Communications  Published:26 July 2025
DOI:https://doi.org/10.1038/s41467-025-62262-3

稲の胚形成欠損性状を制御する重要遺伝子OsBZR4を同定(Scientists Identify Key Gene OsBZR4 Regulating Embryoless Rice Traits with Agricultural Potential)

Abstract

Embryoless rice is valuable for studying early seed development and has great breeding potential, however, related research remains limited. Here, we show that mutations in OsBZR4, encoding brassinazole-resistance 4, lead to 60–100% embryoless seeds across different cultivars. OsBZR4 is specifically expressed at the scutellum-endosperm interface and regulates auxin levels and distribution during early embryo development. OsBZR4 represses the expression of YUC4 and PIN5b. Exogenous auxin and overexpression of YUC4 enhance the embryoless ratio, whereas the auxin transport inhibitor N-1-naphthylphthalamic acid (NPA) decrease it. Higher temperatures increase the embryoless ratio in bzr4 mutant lines. The expression of OsPIL13 is induced by high temperature, and its overexpression enhances the embryoless ratio in both wild type and bzr4 plants. Introducing bzr4 mutant allele into some elite cultivars can improve milled rice yield and storability. Collectively, manipulating OsBZR4 can lead to the development of thermosensitive embryoless rice varieties with increased energy reserves and improved storability, potentially enabling novel rice production technologies.

1202農芸化学
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