Tomato SlIDA has a critical role in tomato fertilization by modifying ROS homeostasis

提出问题-1：The timing and spatial distribution of reactive oxygen species (ROS) and programmed cell death (PCD) are central to these processes, but the regulatory mechanism of ROS production is not well understood.

背景回顾-2：Inflorescence deficient in abscission (IDA) is implicated in many plant development and responses to environmental stimuli.

提出问题-2：However, their role in reproductive development is still unknown.

结果：We generated tomato knockout lines (CR‐slida) of an IDA homolog (SlIDA) that is expressed in the tapetum, septum, and pollen tube, and observed a severe male gamete defect. Further analysis indicated that there was a PCD defect in the tapetum and septum and a failure of anther dehiscence in the CR‐slida lines, likely related to insufficient ROS signal. LC‐MS/MS identified mature SlIDA as a 14‐mer EPIP peptide, which was shown to be secreted and a complementation experiment showed that application of a synthetic 14‐mer EPIP peptide rescued the CR‐slida defect and enhanced the ROS signal. Moreover, the application of the ROS scavengers DPI or Mn‐TMPP suppressed peptide function.

结论：Collectively, our results revealed that SlIDA plays an essential role in pollen development and pollen tube elongation by modulating ROS homeostasis.

 摘  要 

花药发育和花粉管伸长是植物授粉和受精的关键步骤。活性氧物质ROS的时间和空间分布以及程序性细胞死亡PCD是这些生物学进程的关键，但是目前ROS形成的分子调控机制还不清楚。花序脱落缺陷IDA在许多植物的发育过程中都有发现，并且响应与环境的刺激。然而，其对于生殖发育的影响还不清楚。番茄中，IDA同源基因SlIDA在绒毡层、隔膜和花粉管中表达，作者在本文中构建了番茄SlIDA基因的敲除株系CR‐slida，并观察到了严重的雄配子缺陷。进一步的根系显示，CR‐slida株系的绒毡层和隔膜存在PCD缺陷，且花药不能开裂，有可能与匮乏的ROS信号有关。LC‐MS/MS鉴定了成熟的SlIDA蛋白作为一个14-mer的EPIP多肽，该多肽会被分泌，互补试验显示外施合成的14-mer EPIP多肽能够拯救CR‐slida株系的缺陷表型，并且增强ROS信号。此外，通过外施ROS清除剂DPI或者Mn‐TMPP能够抑制多肽的功能。综上，本文的结果揭示了番茄中SlIDA基因通过调控ROS内稳态在花粉的发育以及花粉管的伸长中发挥重要作用。

 通讯作者