Ves-Urai Parthompong, Krobthong Sucheewin, Thongsuk Karnpitcha, Roytrakul Sittiruk, Yokthongwattana Chotika
Interdisciplinary Program in Genetic Engineering, Graduate School, Kasetsart University, Bangkok, Thailand.
National Center for Genetic Engineering and Biotechnology, 113 Thailand Science Park, Phahonyothin Rd., Pathumthani, 12120, Thailand.
Planta. 2021 Feb 16;253(3):68. doi: 10.1007/s00425-021-03583-7.
Secretome analysis of a salt-tolerant and control Chlamydomonas reinhardtii revealed 514 differentially expressed proteins. Membrane transport and trafficking, signal transduction and channel proteins were up-regulated in the ST secretome. Salinity is a major abiotic stress that limits crop production worldwide. Multiple adverse effects have been reported in many living organisms exposed to high-saline concentrations. Chlamydomonas reinhardtii is known for secreting proteins in response to many environmental stresses. A salinity-tolerant (ST) strain of Chlamydomonas has been developed, whose cells were able to grow at 300 mM NaCl. The current study analyzed the secretomes of ST grown in TAP medium supplemented with 300 mM NaCl and the laboratory strain CC-503 grown in TAP medium without NaCl supplement. In total, 514 secreted proteins were identified of which 203 were up-regulated and 110 were down-regulated. Bioinformatic analysis predicted 168 proteins to be secreted or in the conventional secretory pathway. Out of these, 70 were up-regulated, while 51 proteins were down-regulated. Proteins involved in membrane transport and trafficking, signal transduction and channel proteins were altered in their expression in the ST secretome, suggesting the response of saline stress acts toward not only the intracellular pool of proteins but also the extracellular proteins. This also suggested that the secreted proteins might have roles in the extracellular space. Signal peptide (SP) prediction revealed that almost 40% of the predicted secreted proteins contained a signal peptide; however, a high proportion of proteins lacked an SP, suggesting that these proteins might be secreted through an unconventional protein secretion pathway.
对耐盐莱茵衣藻和对照莱茵衣藻的分泌蛋白组分析揭示了514种差异表达蛋白。膜运输与转运、信号转导和通道蛋白在耐盐分泌蛋白组中上调。盐度是限制全球作物产量的主要非生物胁迫。在许多暴露于高盐浓度的生物体中已报道了多种不利影响。莱茵衣藻以响应多种环境胁迫分泌蛋白质而闻名。已培育出一种耐盐（ST）的莱茵衣藻菌株，其细胞能够在300 mM NaCl条件下生长。本研究分析了在添加300 mM NaCl的TAP培养基中生长的ST菌株以及在不添加NaCl的TAP培养基中生长的实验室菌株CC-503的分泌蛋白组。总共鉴定出514种分泌蛋白，其中203种上调，110种下调。生物信息学分析预测有168种蛋白会被分泌或处于传统分泌途径中。其中，70种上调，51种下调。参与膜运输与转运、信号转导和通道蛋白的蛋白在耐盐分泌蛋白组中的表达发生了改变，这表明盐胁迫的响应不仅作用于细胞内的蛋白质库，也作用于细胞外蛋白质。这也表明分泌蛋白可能在细胞外空间发挥作用。信号肽（SP）预测显示，几乎40%的预测分泌蛋白含有信号肽；然而，很大一部分蛋白缺乏信号肽，这表明这些蛋白可能通过非传统蛋白质分泌途径分泌。
