中国科学院遗传与发育生物学研究所曹晓风、陈宇航和长沙杂交水稻国家重点实验室杨远柱研究组合作取得进展。他们发现2′,3′-环磷酸tRNA修复受损导致水稻热敏基因引起的雄性不育。相关论文于2024年9月9日发表于国际学术期刊《细胞研究》杂志。

研究人员发现TMS5是一种tRNA 2′,3′-环磷酸酶。tms5突变会导致2′,3′-环磷酸（cP）-ΔCCA-tRNAs（以cP结尾的不含3′CCA的tRNAs）的积累，高温会加剧这种积累，并降低成熟tRNAs的丰度，尤其是丙氨酸tRNAs（tRNA-Alas）。在tms5突变体中过表达tRNA-Alas可使雄性的繁殖力恢复到70%。

值得注意的是，通过敲除编码cP-ΔCCA-tRNA生成酶的OsVms1，tms5突变体的雄性繁殖力在高温下完全恢复。该研究揭示了水稻中tms5诱导TGMS的基本机制，为进一步改进杂交作物育种中TGMS提供了启示。

据介绍，杂交水稻在亚洲广泛种植，其具有抗病原性和优异的产量，为全球粮食安全提供了保障。双系杂交水稻系统主要利用对光敏/热敏基因敏感的雄性不育（P/TGMS）突变体，是当今最主要的杂交水稻育种技术。在现有的双系杂交水稻育种技术中，95%以上的双系杂交水稻品系都存在对热敏感基因雄性不育5（TMS5）的突变。之前的研究表明TMS5带有核糖核酸酶ZS1的突变。尽管TMS5对培育优良的水稻品系非常重要，但介导TGMS的机制仍然未知。

附：英文原文

Title: Impaired 2′,3′-cyclic phosphate tRNA repair causes thermo-sensitive genic male sterility in rice

Author: Yan, Bin, Liu, Chunyan, Sun, Jing, Mao, Yang, Zhou, Can, Li, Ji, Liu, Wei, Li, Shengdong, Yan, Wei, Fu, Chenjian, Qin, Peng, Fu, Xingxue, Zhao, Xinghui, Song, Xianwei, Nie, Jiawei, Gao, Feng, Yang, Yuanzhu, Chen, Yuhang, Cao, Xiaofeng

Issue&Volume: 2024-09-09

Abstract: Hybrid rice, widely planted in Asia, is pathogen resistant and has superior yields, making it a major contributor to global food security. The two-line hybrid rice system, which utilizes mutants exhibiting photo-/thermo-sensitive genic male sterility (P/TGMS), is the leading hybrid rice breeding technology. Mutations in THERMO-SENSITIVE GENIC MALE STERILE 5 (TMS5) accounts for over 95% of current TGMS lines. We previously found that tms5 carries a mutation in ribonuclease ZS1. Despite its importance for breeding robust rice lines, the mechanism underlying tms5-mediated TGMS remains elusive. Here, we demonstrate that TMS5 is a tRNA 2′,3′-cyclic phosphatase. The tms5 mutation leads to accumulation of 2′,3′-cyclic phosphate (cP)-ΔCCA-tRNAs (tRNAs without 3′ CCA ended with cP), which is exacerbated by high temperatures, and reduction in the abundance of mature tRNAs, particularly alanine tRNAs (tRNA-Alas). Overexpression of tRNA-Alas in the tms5 mutant restores male fertility to 70%. Remarkably, male fertility of tms5 mutant is completely restored at high temperatures by knocking out OsVms1 which encodes the enzyme for cP-ΔCCA-tRNA generation. Our study reveals the mechanism underlying tms5-mediated TGMS in rice and provides mechanistic insight into the further improvement of TGMS in hybrid crop development.

DOI: 10.1038/s41422-024-01012-4

Source: https://www.nature.com/articles/s41422-024-01012-4