School of Life Sciences, University of Warwick, Coventry, UK.
Center for Bioinformatics and Computational Biology, University of Delaware, Newark, DE, USA.
Nat Plants. 2021 Jan;7(1):34-41. doi: 10.1038/s41477-020-00818-5. Epub 2021 Jan 4.
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 losses. Therefore, understanding the precise molecular mechanisms that underpin plant fertility under environmental constraints is critical to safeguarding future food production. 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.
尽管植物能够耐受一系列环境条件，但环境温度的飙升会影响植物的生育能力，导致种子产量减少和显著的经济损失。因此，了解支持植物在环境胁迫下生育能力的精确分子机制对于保障未来的粮食生产至关重要。在这里，我们鉴定了两个 Argonaute 样蛋白，它们的活性对于维持玉米植株在高温下的雄性育性是必需的。我们发现，MALE-ASSOCIATED ARGONAUTE-1 和 -2 与减数分裂前小孢子囊中温度诱导的相分期二级小 RNA 相关，对于控制雄性减数分裂起始细胞中逆转座子的活性至关重要。生化和结构分析揭示了雄性相关 Argonaute 活性及其与逆转座子 RNA 靶标的相互作用如何通过一组高度保守的、位于表面的丝氨酸残基的动态磷酸化来调节。我们的研究结果表明，在植物中，依赖 Argonaute 的 RNA 指导的监测机制对于在环境受限条件下维持雄性育性至关重要，通过控制雄性生殖细胞中转座子的诱变活性。
