Shenzhen Key Laboratory of Marine Bioresource and Eco-Environmental Science, Shenzhen Engineering Laboratory for Marine Algal Biotechnology, Guangdong Provincial Key Laboratory for Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China.
Int J Mol Sci. 2021 Oct 26;22(21):11539. doi: 10.3390/ijms222111539.
The papain-like cysteine proteases (PLCPs), the most important group of cysteine proteases, have been reported to participate in the regulation of growth, senescence, and abiotic stresses in plants. However, the functions of PLCPs and their roles in stress response in microalgae was rarely reported. The responses to different abiotic stresses in were often observed, including growth regulation and astaxanthin accumulation. In this study, the cDNA of containing 1515 bp open reading frame (ORF) was firstly cloned from by RT-PCR. The analysis of protein domains and molecular evolution showed that was closely related to from . The expression pattern analysis revealed that it significantly responds to NaCl stress in . Subsequently, transformants expressing in were obtained and subjected to transcriptomic analysis. Results showed that might affect the cell cycle regulation and DNA replication in transgenic , resulting in abnormal growth of transformants. Moreover, the expression of might increase the sensitivity to NaCl stress by regulating ubiquitin and the expression of WD40 proteins in microalgae. Furthermore, the expression of might improve chlorophyll content by up-regulating the expression of NADH-dependent glutamate synthases in . This study indicated for the first time that was involved in the regulation of cell growth, salt stress response, and chlorophyll synthesis in microalgae. Results in this study might enrich the understanding of PLCPs in microalgae and provide a novel perspective for studying the mechanism of environmental stress responses in .
木瓜蛋白酶样半胱氨酸蛋白酶（PLCPs）是最重要的半胱氨酸蛋白酶组之一，据报道其参与植物的生长、衰老和非生物胁迫的调控。然而，PLCPs 的功能及其在微藻胁迫响应中的作用很少有报道。经常观察到 对不同非生物胁迫的响应，包括生长调节和虾青素积累。在本研究中，首次通过 RT-PCR 从 中克隆了含有 1515bp 开放阅读框（ORF）的 cDNA。蛋白结构域和分子进化分析表明， 与 来自 的 密切相关。表达模式分析表明，它在 中对 NaCl 胁迫有显著响应。随后，获得了表达 的 转化体，并进行了转录组分析。结果表明， 在转基因 中可能通过影响细胞周期调控和 DNA 复制，导致转化体异常生长。此外， 通过调节泛素和 WD40 蛋白在微藻中的表达，可能增加对 NaCl 胁迫的敏感性。此外， 在 中可能通过上调 NADH 依赖性谷氨酸合酶的表达来提高叶绿素含量。本研究首次表明 参与了微藻细胞生长、盐胁迫响应和叶绿素合成的调控。本研究结果可能丰富了对微藻中 PLCPs 的理解，并为研究微藻环境胁迫响应机制提供了新的视角。
