In rice breeding, thermosensitive genic male sterility (TGMS) lines based on the tms5 locus have been extensively employed. Here, we reported a novel rice TGMS line ostms15 (Oryza sativa ssp. japonica ZH11) which show male sterility under high temperature and fertility under low temperature. Field evaluation from 2018 to 2021 revealed that its sterility under high temperature is more stable than that of tms5 (ZH11), even with occasional low temperature periods, indicating its considerable value for rice breeding. OsTMS15 encodes an LRR-RLK protein MULTIPLE SPOROCYTE1 (MSP1) which was reported to interact with its ligand to initiate tapetum development for pollen formation. In ostms15, a point mutation from GTA (Val) to GAA (Glu) in its TIR motif of the LRR region led to the TGMS phenotype. Cellular observation and gene expression analysis showed that the tapetum is still present in ostms15, while its function was substantially impaired under high temperature. However, its tapetum function was restored under low temperature. The interaction between mOsTMS15 and its ligand was reduced while this interaction was partially restored under low temperature. Slow development was reported to be a general mechanism of P/TGMS fertility restoration. We propose that the recovered protein interaction together with slow development under low temperature compensates for the defective tapetum initiation, which further restores ostms15 fertility. We used base editing to create a number of TGMS lines with different base substitutions based on the OsTMS15 locus. This work may also facilitate the mechanistic investigation and breeding of other crops.

中文翻译：

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低温补偿有缺陷的绒毡层起始，以恢复新型 TGMS 系 ostms15 的育性

在水稻育种中，基于tms5基因座的热敏基因雄性不育（TGMS）品系已得到广泛应用。在这里，我们报道了一个新的水稻TGMS品系ostms15（Oryza sativa ssp. japonica ZH11），该品系在高温下表现出雄性不育性，在低温下表现出育性。2018年至2021年的田间评价表明，即使偶有低温期，其高温不育性也比tms5 （ZH11）更稳定，表明其对水稻育种具有相当大的价值。OsTMS15编码 LRR-RLK 蛋白多孢子细胞 1 (MSP1)，据报道，该蛋白与其配体相互作用，启动绒毡层发育以形成花粉。在ostms15中，LRR 区域的 TIR 基序中从 GTA (Val) 到 GAA (Glu) 的点突变导致了 TGMS 表型。细胞观察和基因表达分析表明， ostms15中绒毡层仍然存在，但其功能在高温下明显受损。但在低温下其绒毡层功能又得以恢复。mOsTMS15与其配体之间的相互作用减弱，但在低温下这种相互作用部分恢复。据报道，发育缓慢是 P/TGMS 生育力恢复的一般机制。我们认为恢复的蛋白质相互作用以及低温下的缓慢发育弥补了绒毡层起始的缺陷，从而进一步恢复了ostms15 的育性。我们使用碱基编辑创建了许多基于 OsTMS15 基因座具有不同碱基替换的 TGMS 系。这项工作也可能有助于其他作物的机械研究和育种。