Environmental pH signals the release of monosaccharides from cell wall in coral symbiotic alga
Environmental pH signals the release of monosaccharides from cell wall in coral symbiotic alga
复制标题
DOI：
10.1101/2022.07.03.498615
复制
发表时间：
2022-07
期刊：
影响因子：
7.7
通讯作者：
Yuu Ishii;Hironori Ishii;Takeshi Kuroha;R. Yokoyama;R. Deguchi;K. Nishitani;J. Minagawa;M. Kawata;Shunichi Takahashi;Shinichiro Maruyama
中科院分区：
文献类型：
--
作者：
Yuu Ishii;Hironori Ishii;Takeshi Kuroha;R. Yokoyama;R. Deguchi;K. Nishitani;J. Minagawa;M. Kawata;Shunichi Takahashi;Shinichiro Maruyama
造礁珊瑚由于拥有内共生藻类而在营养稀少的环境中茁壮成长。局限于细胞内共生体的低pH内部，藻类共生体为珊瑚宿主提供光合作用固定的碳。然而，目前还不清楚碳是如何从藻类共生体中释放出来被宿主吸收的。在这里，我们用培养的共生甲藻BreVium sp.展示了，pH的下降直接加速了单糖，即葡萄糖和半乳糖的释放到环境中。在低pH条件下，灯盏花细胞表面结构发生变形，纤维素酶相关基因表达显著上调。重要的是，单糖的释放被纤维素酶抑制剂葡萄糖吡喃糖苷抑制，将碳的释放与agal细胞壁的降解联系在一起。我们的结果表明，在珊瑚礁生态系统中，低pH是纤维素酶介导的单糖从藻细胞壁上释放的信号，是一种环境反应。
Reef-building corals thrive in oligotrophic environments due to their possession of endosymbiotic algae. Confined to the low pH interior of the symbiosome within the cell, the algal symbiont provides the coral host with photosynthetically fixed carbon. However, it remains unknown how carbon is released from the algal symbiont for uptake by the host. Here we show, using cultured symbiotic dinoflagellate, Breviolum sp., that decreases in pH directly accelerates the release of monosaccharides, i.e., glucose and galactose, into the ambient environment. Under low pH conditions, the cell surface structures were deformed and genes related to cellulase were significantly upregulated in Breviolum. Importantly, the release of monosaccharides was suppressed by the cellulase inhibitor, glucopyranoside, linking the release of carbon to degradation of the agal cell wall. Our results suggest that the low pH signals the cellulase-mediated release of monosaccharides from the algal cell wall as an environmental response in coral reef ecosystems.