Thermosensitive genic male sterility (TGMS) lines serve as the major genetic resource for two-line hybrid breeding in rice. However, their unstable sterility under occasional low temperatures in summer highly limits their application. In this study, we identified a novel rice TGMS line, ostms18, of cultivar ZH11 (Oryza sativa ssp. japonica). ostms18 sterility is more stable in summer than the TGMS line carrying the widely used locus tms5 in the ZH11 genetic background, suggesting its potential application for rice breeding. The ostms18 TGMS trait is caused by the point mutation from Gly to Ser in a glucose-methanol-choline (GMC) oxidoreductase; knockout of the oxidoreductase was previously reported to cause complete male sterility. Cellular analysis revealed the pollen wall of ostms18 to be defective, leading to aborted pollen under high temperature. Further analysis showed that the tapetal transcription factor OsMS188 directly regulates OsTMS18 for pollen wall formation. Under low temperature, the flawed pollen wall in ostms18 is sufficient to protect its microspore, allowing for development of functional pollen and restoring fertility. We identified the orthologous gene in Arabidopsis. Although mutants for the gene were fertile under normal conditions (24°C), fertility was significantly reduced under high temperature (28°C), exhibiting a TGMS trait. A cellular mechanism integrated with genetic mutations and different plant species for fertility restoration of TGMS lines is proposed.

中文翻译：

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葡萄糖-甲醇-胆碱氧化还原酶突变导致水稻和拟南芥热敏性雄性不育基因

热敏基因雄性不育（TGMS）品系是水稻两系杂交育种的主要遗传资源。然而，它们在夏季偶尔低温下不稳定的不育性极大地限制了它们的应用。在这项研究中，我们鉴定了一个新的水稻 TGMS 系ostms18，它是栽培品种 ZH11（Oryza sativa ssp. japonica）。ostms18不育在夏季比携带 ZH11 遗传背景中广泛使用的基因座tms5的 TGMS 系更稳定，表明其在水稻育种中的潜在应用。ostms18 _TGMS 性状是由葡萄糖-甲醇-胆碱 (GMC) 氧化还原酶中 Gly 到 Ser 的点突变引起的；先前报道敲除氧化还原酶会导致完全雄性不育。细胞分析显示ostms18的花粉壁有缺陷，导致花粉在高温下流产。进一步分析表明，绒毡层转录因子OsMS188直接调节OsTMS18的花粉壁形成。低温下ostms18花粉壁有缺陷足以保护其小孢子，使花粉发育并恢复生育能力。我们鉴定了拟南芥中的直系同源基因。尽管该基因的突变体在正常条件（24°C）下可育，但在高温（28°C）下可育性显着降低，表现出 TGMS 性状。提出了一种整合基因突变和不同植物物种的TGMS系育性恢复的细胞机制。