Spontaneous fertility reversion has been documented in cytoplasmic male sterile (CMS) plants of several species, influenced in frequency by nuclear genetic background. In this study, we found that MutS HOMOLOG1 (MSH1) mediates fertility reversion via substoichiometric shifting (SSS) of the CMS‐associated mitochondrial Open Reading Frame 220 (ORF220), a process that may be regulated by pollination signalling in Brassica juncea. We show that plants adjust their growth and development in response to unsuccessful pollination. Measurable decrease in MSH1 transcript levels and evidence of ORF220 SSS under non‐pollination conditions suggest that this nuclear‐mitochondrial interplay influences fertility reversion in CMS plants in response to physiological signals. Suppression of MSH1 expression induced higher frequency SSS in CMS plants than occurs normally. Transcriptional analysis of floral buds under pollination and non‐pollination conditions, and the response of MSH1 expression to different sugars, supports the hypothesis that carbon flux is involved in the pollination signalling of fertility reversion in CMS plants. Our findings suggest that facultative gynodioecy as a reproductive strategy may incorporate environmentally responsive genes like MSH1 as an “on–off” switch for sterility–fertility transition under ecological conditions of reproductive isolation.

中文翻译：

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MutS HOMOLOG1介导环境对细胞质雄性不育芥菜的育性回复

在几种物种的细胞质雄性不育（CMS）植物中，自发的繁殖力恢复已有记录，其频率受核遗传背景的影响。在这项研究中，我们发现MutS HOMOLOG1（MSH1）通过与CMS相关的线粒体开放阅读框220（ORF220）的亚化学计量位移（SSS）介导生育力的回复，该过程可能受芥菜授粉信号传导的调节。我们表明植物对不成功的授粉会调节其生长和发育。MSH1成绩单水平显着下降和ORF220的证据非授粉条件下的SSS表明，这种核-线粒体相互作用对CMS植株响应生理信号的回复具有影响。的抑制MSH1表达在CMS植物诱导更高频率SSS比通常发生。在授粉和非授粉条件下对花蕾的转录分析以及MSH1表达对不同糖的响应，支持了碳通量参与CMS植物育性回复的授粉信号传递的假说。我们的研究结果表明，兼性生殖道生殖作为一种生殖策略，可能将环境响应基因如MSH1纳入生殖隔离生态条件下的不育－生育力过渡的“通断”开关。