A transposon surveillance mechanism that safeguards plant male fertility during stress
A transposon surveillance mechanism that safeguards plant male fertility during stress
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DOI：
10.1038/s41477-020-00818-5
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发表时间：
2021-01-04
期刊：
影响因子：
18
通讯作者：
Gutierrez-Marcos, Jose
中科院分区：
文献类型：
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作者：
Lee, Yang-Seok;Maple, Robert;Gutierrez-Marcos, Jose
MALE-ASSOCIATED ARGONATE-1和-2促进热诱导的phasiRNA产生，其抑制热激活的反转录转座子并保护雄性生育力。虽然植物能够承受一系列的环境条件，但环境温度的峰值会影响植物的生育力，导致种子产量降低和显著的经济损失（1，2）。因此，了解在环境限制下支撑植物生育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，我们确定了两个Argonaute样蛋白，其活性是在高温下维持玉米植株雄性育性所必需的。我们发现，MALE-ASSOCIATED ARGONAUTE-1和-2与温度诱导的减数分裂前花药中的阶段性次级小RNA相关，并且对于控制雄性性母细胞初始细胞中反转录转座子的活性至关重要。生物化学和结构分析揭示了男性相关的Argonaute活性及其与逆转录转座子RNA靶标的相互作用如何通过一组高度保守的表面丝氨酸残基的动态磷酸化来调节。我们的研究结果表明，Argonaute依赖的，RNA引导的监视机制是至关重要的，在植物中维持雄性生育力的环境约束条件下，通过控制转座子在雄性生殖细胞的诱变活性。
MALE-ASSOCIATED ARGONAUTE-1 and -2 promote heat-induced phasiRNA production, which represses heat-activated retrotransposons and protects male fertility. This activity is regulated by heat-mediated hypophosphorylation of the Argonaute proteins.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(1,2). Therefore, understanding the precise molecular mechanisms that underpin plant fertility under environmental constraints is critical to safeguarding future food production(3). 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.