Reproductive Responses to Wounding and Heat Stress in Gametophytic Thalli of the Red Alga Pyropia yezoensis
Reproductive Responses to Wounding and Heat Stress in Gametophytic Thalli of the Red Alga Pyropia yezoensis
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DOI：
10.3389/fmars.2020.00394
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发表时间：
2020-05-28
影响因子：
3.7
通讯作者：
Mikami, Koji
中科院分区：
文献类型：
--
作者：
Suda, Masahiro;Mikami, Koji
从生长到繁殖的过渡时间对海藻生命周期的调节至关重要。多变的环境条件会对海藻造成压力，并促使它们在生长和繁殖之间进行权衡。在这里，我们证明了环境胁迫可以诱导海洋红藻yezoensis的配子体菌体的生殖反应。外植体的切除加速了无性单孢子和有性碳孢子的释放。在切除外植体之前进行3天的黑暗处理，增强了藻类对伤害的敏感性。相比之下，25摄氏度的热应激刺激了愈伤组织的产生，愈伤组织是一种具有多层细胞层的随机分裂细胞的三维聚集。愈伤组织产生新的配子体体，形状正常；因此，愈伤组织的形成被认为是藻类在热胁迫条件下增加菌体数量的无性繁殖策略之一。我们的研究结果表明，伤害和热胁迫可以重置生殖时间，因此配子体体在不同的胁迫条件下使用各种不同的生殖策略。这些发现提供了对环境压力诱导繁殖作为海藻生命周期权衡的见解。
The timing of the transition from growth to reproduction is essential for the regulation of the seaweed life cycle. Variable environmental conditions can stress seaweeds and promote trade-offs between their growth and reproduction. Here, we demonstrate that reproductive responses can be induced by environmental stresses in the gametophytic thalli of the marine red alga Pyropia yezoensis. Excision of explants accelerated release of asexual monospores and sexual carpospores. The algal sensitivity to wounding was enhanced by a 3-day dark treatment prior to the excision of the explants. By contrast, heat stress at 25 degrees C stimulated the production of a callus, a three-dimensional aggregation of randomly divided cells with multiple cell layers. This callus produced new gametophytic thalli with a normal shape; therefore, callus formation is thought to be one of the asexual reproductive strategies used by the alga to increase the number of thalli under heat stress conditions. Our results demonstrate that wounding and heat stress can reset the timing of reproduction and that gametophytic thalli therefore use a variety of distinct reproductive strategies under different stress conditions. These findings provide insights into the induction of reproduction by environmental stresses as a life cycle trade-off in seaweeds.