Data_Sheet_1_Comparative Gene Expression and Physiological Analyses Reveal Molecular Mechanisms in Wound-Induced Spore Formation in the Edible Seaweed Nori.PDF

Genetic reprogramming of differentiated cells is studied broadly in multicellular Viridiplantae as an adaptation to herbivory or damage; however, mechanisms underlying cell development and redifferentiation are largely unknown in red algae, their nearest multicellular relatives. Here we investgate cell reprogramming in the widely cultivated, edible seaweed Neopyropia yezoesis (“nori”), where vegetative cells in wounded blades differentiate and release as large numbers of asexual spores. Based upon physiological changes and transcriptomic dynamics after wound stress in N. yezoensis and its congener Neoporphyra haitanensis, another cultivar that does not differentiate spores after wounding, we propose a three-phase model of wound-induced spore development in N. yezoensis. In Phase I, propagation of ROS by RBOH and SOD elicites systematic transduction of the wound signal, while Ca2+ dependent signaling induces cell reprogramming. In Phase II, a TOR signaling pathway and regulation of cyclin and CDK genes result in cell divisions that spread inward from the wound edge. Once sporangia form, Phase III involves expression of proteins required for spore maturation and cell wall softening. Our analyses not only provide the first model for core molecular processes controlling cellular reprogramming in rhodophytes, but also have practical implications for achieving greater control over seeding in commercial nori farming.

分化细胞的遗传重编程作为应对植食性胁迫或机械损伤的适应策略，已在多细胞绿色植物界（Viridiplantae）中得到广泛研究；而作为绿色植物最近缘多细胞类群的红藻（red algae），其细胞发育与再分化的核心机制仍未被充分阐明。本研究以广泛栽培的可食用海藻条斑紫菜（Neopyropia yezoesis，俗称"nori"）为研究对象，探讨其细胞重编程过程：该物种受伤叶状体的营养细胞可发生分化并释放大量无性孢子。我们以条斑紫菜及其近缘物种坛紫菜（Neoporphyra haitanensis，该物种受伤后无法分化产生孢子）作为对照物种，基于二者在损伤胁迫下的生理变化与转录组动态特征，提出了条斑紫菜损伤诱导孢子发育的三阶段模型。第一阶段：呼吸爆发氧化酶同源物（RBOH, Respiratory Burst Oxidase Homolog）与超氧化物歧化酶（SOD, Superoxide Dismutase）介导活性氧（ROS, Reactive Oxygen Species）的增殖，触发损伤信号的系统性传导；同时钙离子（Ca²+）依赖型信号通路诱导细胞重编程。第二阶段：靶标雷帕霉素（TOR, Target of Rapamycin）信号通路，以及细胞周期蛋白（cyclin）与细胞周期蛋白依赖性激酶（CDK, Cyclin-Dependent Kinase）基因的调控，介导细胞分裂从伤口边缘向内扩散。第三阶段：孢子囊形成后，参与孢子成熟与细胞壁软化的相关蛋白开始表达。本研究不仅首次构建了红藻门（Rhodophyta）物种中调控细胞重编程的核心分子过程模型，同时对商用紫菜养殖中实现更精准的种苗繁育调控具有重要的实际应用价值。