Reactive oxygen species (ROS) signalling has a multitude of roles in cellular processes throughout biology. We hypothesized that red algal fertilization may offer an interesting model to study ROS-mediated signalling, as the stages of fertilization are complex and unique. We detected the localization of ROS production microscopically and monitored the expression of three homologues of NADPH oxidase in reproductive cells during fertilization. ROS were instantaneously produced by spermatia (sperm) when they attached to female trichogynes, diffused across the cell membrane in the form of H2O2, and triggered ROS generation in the carpogonium (egg) as well as carpogonial branch cells which are not in direct contact with spermatia. The expression of NADPH oxidase homologues, RESPIRATORY BURST OXIDASE HOMOLOGUES (BmRBOHs), began to be up-regulated in the female plant upon gamete binding, peaking during the fertilization process and descending back to their original level after fertilization. Pre-treatment with diphenylene iodonium or caffeine blocked gene expression as well as H2O2 production. Post-fertilization development was also inhibited when the redox state of the plants was perturbed with H2O2 at any time before or after the fertilization. Our results suggest that H2O2 acts as an auto-propagating signalling molecule, possibly through Ca2+ channel activation, and regulates gene expression in fertilization as well as post-fertilization development in red algae.

中文翻译：

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过氧化氢信号介导红藻 Bostrychia moritziana 的受精和受精后发育

活性氧 (ROS) 信号传导在整个生物学的细胞过程中具有多种作用。我们假设红藻受精可能为研究 ROS 介导的信号传导提供一个有趣的模型，因为受精阶段是复杂而独特的。我们在显微镜下检测了 ROS 产生的定位，并监测了受精过程中生殖细胞中三种 NADPH 氧化酶同源物的表达。ROS 是由精子细胞（精子）在附着于雌性毛囊时立即产生的，以 H2O2 的形式扩散穿过细胞膜，并在不直接接触的毛囊细胞（卵）和毛囊分支细胞中触发 ROS 的产生。精子。NADPH 氧化酶同源物呼吸突发氧化酶同源物 (BmRBOHs) 的表达，配子结合后在雌株中开始上调，在受精过程中达到峰值，受精后下降回原来的水平。用二亚苯基碘鎓或咖啡因预处理阻断了基因表达以及 H2O2 的产生。当植物的氧化还原状态在受精前或受精后的任何时间被 H2O2 干扰时，受精后的发育也受到抑制。我们的研究结果表明，H2O2 作为一种自动传播的信号分子，可能通过 Ca2+ 通道激活，并调节红藻受精过程中的基因表达以及受精后的发育。用二亚苯基碘鎓或咖啡因预处理阻断了基因表达以及 H2O2 的产生。当植物的氧化还原状态在受精前或受精后的任何时间被 H2O2 干扰时，受精后的发育也受到抑制。我们的研究结果表明，H2O2 作为一种自动传播的信号分子，可能通过 Ca2+ 通道激活，并调节红藻受精过程中的基因表达以及受精后的发育。用二亚苯基碘鎓或咖啡因预处理阻断了基因表达以及 H2O2 的产生。当植物的氧化还原状态在受精前或受精后的任何时间被 H2O2 干扰时，受精后的发育也受到抑制。我们的研究结果表明，H2O2 作为一种自动传播的信号分子，可能通过 Ca2+ 通道激活，并调节红藻受精过程中的基因表达以及受精后的发育。