Nature Plants|转座子监控机制可在胁迫期间保护植物雄性育性

尽管植物能够承受各种环境条件，但是环境温度的峰值会影响植物的繁殖力，从而导致种子产量下降和明显的经济损失1,2。 因此，了解在环境限制下支撑植物繁殖力的精确分子机制对于保护未来的粮食生产至关重要。 

在这里，我们鉴定了两个类似Argonaute的蛋白，它们的活性对于维持高温下玉米植物的雄性育性是必需的。

我们发现，MALE-associciated ARGONAUTE-1和-2与减数分裂前花药中温度诱导的阶段性次级小RNA缔合，并且对于控制雄性减数分裂母细胞中逆转座子的活性至关重要。

生化和结构分析表明，如何通过一系列高度保守的，位于表面的丝氨酸残基的动态磷酸化来调节雄性相关的Argonaute活性及其与逆转座子RNA靶标的相互作用。

我们的结果表明，通过控制雄性生殖细胞中转座子的诱变活性，依赖Argonaute的RNA指导的监视机制对于植物在环境受限的条件下维持雄性育性至关重要。

Although plants are able to withstand a range of environmental conditions, spikes in ambient temperature can impact plant fertility causing reductions in seed yield and notable economic losses1,2. Therefore, understanding the precise molecular mechanisms that underpin plant fertility under environmental constraints is critical to safeguarding future food production3. Here, we identified two Argonaute-like proteins whose activities are required to sustain male fertility in maize plants under high temperatures. We found that MALE-ASSOCIATED ARGONAUTE-1 and -2 associate with temperature-induced phased secondary small RNAs in pre-meiotic anthers and are essential to controlling the activity of retrotransposons in male meiocyte initials. Biochemical and structural analyses revealed how male-associated Argonaute activity and its interaction with retrotransposon RNA targets is modulated through the dynamic phosphorylation of a set of highly conserved, surface-located serine residues. Our results demonstrate that an Argonaute-dependent, RNA-guided surveillance mechanism is critical in plants to sustain male fertility under environmentally constrained conditions, by controlling the mutagenic activity of transposons in male germ cells.

https://www.nature.com/articles/s41477-020-00818-5

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