Environmental regulation of male fertility is mediated through Arabidopsis bHLH89, 91 and 10

Formation of functional pollen and successful fertilisation relies upon the spatial and temporal regulation of anther and pollen development. This process responds to environmental cues to maintain optimal fertility despite climatic changes. Arabidopsis transcription factors bHLH10,-89,-91 were previously thought to be functionally redundant in their control of male reproductive development, however here we show that they play distinct roles in the integration of light signals to maintain pollen development under different environmental conditions. Combinations of the double and triple bHLH10,-89,-91 mutants were analysed under normal (200μmol/m2/s) and low (50μmol/m2/s) light conditions to determine the impact on fertility. Transcriptomic analysis of a new conditionally sterile bhlh89,91 double mutant shows differential regulation of genes related to sexual reproduction, hormone signal transduction and lipid storage and metabolism under low-light. Here we have shown that bHLH89 and bHLH91 play a role in regulating fertility in response to light, suggesting they function in mitigating environmental variation to ensure fertility is maintained under environmental stress. To elucidate the genetic basis of conditional sterility in the Arabidopsis thaliana bhlh89,91 double mutant here we present an RNA-Seq, comparing floral transcriptomic changes under normal (200μmol/m2/s) and low (50μmol/m2/s) intensity light conditions to wild-type Col-0.

功能性花粉的形成与成功受精，依赖于花药与花粉发育的时空调控。该过程可响应环境信号，即便在气候变化背景下仍能维持最佳育性。此前学界认为拟南芥的碱性螺旋-环-螺旋（basic Helix-Loop-Helix，bHLH）转录因子bHLH10、bHLH89、bHLH91在调控雄性生殖发育时功能冗余，但本研究证实，它们在整合光信号以在不同环境条件下维持花粉发育的过程中发挥着截然不同的作用。本研究在正常光照（200μmol/m²/s）与弱光照（50μmol/m²/s）条件下，对bHLH10、bHLH89、bHLH91的双突变体与三突变体组合开展分析，以明确其对育性的影响。对一株新的条件不育型bhlh89、bhlh91双突变体进行转录组分析后发现，弱光照条件下，该突变体中与有性生殖、激素信号转导以及脂质储存和代谢相关的基因存在差异表达调控。本研究证实，bHLH89与bHLH91参与调控光响应育性，提示二者可通过缓解环境波动，确保植株在环境胁迫下仍能维持育性。为阐明拟南芥（Arabidopsis thaliana）bhlh89、bhlh91双突变体的条件不育遗传基础，本研究构建了RNA测序（RNA-Seq）数据集，对比分析正常光照（200μmol/m²/s）与弱光照（50μmol/m²/s）条件下，该突变体与野生型Col-0的花组织转录组变化。