New Phytol: 上海交通大学张大兵教授在水稻光敏雄性不育系研究中取得新进展

光周期依赖的雄性育性是现代杂交育种的关键因素。一种MYB转录因子CSA是水稻花药糖分配的关键调控因子，其破坏导致光周期敏感雄性不育。然而，有关植物育性对光周期响应的分子机制知之甚少。

在这里，我们获得了另一个水稻光周期敏感雄性不育突变体csa2，它在长日照（LD）条件下表现出半不育性，在短日照（SD）条件下表现正常育性。CSA2在花药中特异表达，在LD条件下对糖分配到花药是必不可少的。

CSA2蛋白在SD条件下以csa特异性模式表达可恢复csa突变体的育性，表明这两种蛋白具有共同的下游调控靶点。

转录组分析也揭示了花药中离散的调控靶点。此外，CSA2在糖转运中的调控作用不仅受花药发育过程中的影响，还受花起始期光周期条件的影响。

总之，我们认为水稻至少进化出两种MYB蛋白CSA2和CSA，分别在LD和SD条件下调控花药中的糖转运。这一发现提供了对光周期雄性不育分子机制的理解。

• Photoperiod-dependent male fertility is a critical enabler of modern hybrid breeding. A MYB transcription factor, CSA, is a key regulator of sugar partitioning in rice anthers, disruption of which causes photoperiod-sensitive male sterility. However, little is known about the molecular mechanisms governing plant fertility in response to photoperiod.

• Here, we have obtained another rice photoperiod-sensitive male sterile mutant, csa2, which exhibits semi-sterility under long-day (LD) conditions, with normal fertility under short-day (SD) conditions. CSA2 specifically expressed in anthers, and here is shown to be indispensable for sugar partitioning to anthers under LD conditions.

• The CSA2 protein can restore the fertility of csa mutants under SD conditions when expressed in a CSA-specific pattern, indicating that the two proteins share common downstream regulatory targets. Transcriptomic analyses also reveal discrete regulatory targets in anthers. Furthermore, the regulatory role of CSA2 in sugar transport was influenced by the photoperiod conditions during floral initiation, not simply during anther development.

• Collectively, we propose that rice evolved at least two MYB proteins, CSA2 and CSA, that regulate sugar transport in anthers under LD and SD conditions, respectively. This finding provides insight into the molecular mechanisms that regulate male fertility in response to photoperiod.

文章来源：

10.1111/nph.17512

文章译文原创；转载请注明来源。

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