A small-RNA pathway that regulate male fertility under heat stress in grasses

与动物不同，植物在有性生殖过程中变得非常脆弱，因为它们经历遗传减少（减数分裂）和大规模的发育和全基因组重编程以产生专门的单倍体配子（例如雄性精子细胞和雌性卵细胞）。由于它们的无柄性质，植物被认为已经进化出应对机制，能够在这些关键时期承受环境温度的波动，然而，这种机制的分子细节还远不清楚。我们最近发现了一类新的小RNA（Hphasi）的存在，其与仅在男性生殖细胞及其周围体细胞中发现的特定Argonaute蛋白一起作用，以在热应激条件下调节男性生育力。我们也有各种各样的证据表明，这种途径在禾本科植物中是保守的。因此，在这项提议中，我们建议使用玉米作为模式作物系统，通过使用各种实验方法（例如，基因工程和基因工程）来确定这种sRNA途径在环境限制下如何调节雄性生育力。发育遗传学、生物化学和分子技术）来揭示所涉及的各种组分和调节因子。我们预计，这项工作不仅将促进我们对谷类植物如何保护其雄性生殖系的基本理解，而且还将提供重要的技术诀窍，以设计谷类作物的新育种工具，使其对气候变化带来的温度胁迫更具弹性。

Unlike in animals, plants become extremely vulnerable during sexual reproduction as they undergo genetic reduction (meiosis) and large-scale developmental and whole-genome reprogramming to produce specialized haploid gametes (e.g. male sperm cells and female egg cells). Due to their sessile nature, plants are thought to have evolved coping mechanisms to be able to withstand fluctuations in ambient temperature during these critical times, however, the molecular details of such mechanisms are far from clear. We recently uncovered the presence of a novel class of small RNAs (Hphasi) acting with specific Argonaute proteins found exclusively in male germ cells and their surrounding somatic cells to regulate male fertility during heat stress conditions. We also have various lines of evidence suggesting that this pathway is conserved in the grasses. In this proposal, we therefore propose to use maize as a model crop system to determine exactly how this sRNA pathway regulates male fertility under environmental constrains, by using a variety of experimental approaches (eg. developmental genetics, biochemical, and molecular techniques) to uncover the various components and regulatory factors involved. We anticipate that this work will not only advance our basic understanding of how cereal plants safeguard their male germline but will also provide important know-how to engineer new breeding tools in cereal crops to make them more resilient to temperature stress brought on by climate change.