PDF(Pubmed)
Abstract：
Asparagine (Asn, N)-linked glycosylation is a conserved process and an essential post-translational modification that occurs on the NXT/S motif of the nascent polypeptides in endoplasmic reticulum (ER). The mechanism of N-glycosylation and biological functions of key catalytic enzymes involved in this process are rarely documented for oomycetes. In this study, an N-glycosylation inhibitor tunicamycin (TM) hampered the mycelial growth, sporangial release, and zoospore production of Phytophthora capsici, indicating that N-glycosylation was crucial for oomycete growth development. Among the key catalytic enzymes involved in N-glycosylation, the PcSTT3B gene was characterized by its functions in P. capsici. As a core subunit of the oligosaccharyltransferase (OST) complex, the staurosporine and temperature sensive 3B (STT3B) subunit were critical for the catalytic activity of OST. The PcSTT3B gene has catalytic activity and is highly conservative in P. capsici. By using a CRISPR/Cas9-mediated gene replacement system to delete the PcSTT3B gene, the transformants impaired mycelial growth, sporangial release, zoospore production, and virulence. The PcSTT3B-deleted transformants were more sensitive to an ER stress inducer TM and display low glycoprotein content in the mycelia, suggesting that PcSTT3B was associated with ER stress responses and N-glycosylation. Therefore, PcSTT3B was involved in the development, pathogenicity, and N-glycosylation of P. capsici.
摘要：
天冬酰胺（Asn，N)-连接的糖基化是在内质网(ER)中新生多肽的NXT/S基序上发生的保守过程和必需的翻译后修饰。卵菌很少记录N-糖基化的机制和参与该过程的关键催化酶的生物学功能。在这项研究中,N-糖基化抑制剂衣霉素（TM）阻碍了菌丝体的生长，孢子囊释放，和辣椒疫霉的游动孢子生产，表明N-糖基化对卵菌的生长发育至关重要。在参与N-糖基化的关键催化酶中，PcSTT3B基因的特征在于其在辣椒假单胞菌中的功能。作为寡糖转移酶（OST）复合物的核心亚基，星形孢菌素和温度敏感3B（STT3B）亚基对OST的催化活性至关重要。PcSTT3B基因具有催化活性，在辣椒中高度保守。通过使用CRISPR/Cas9介导的基因替换系统来删除PcSTT3B基因，转化体损害菌丝生长，孢子囊释放，动物园孢子生产，和毒力。PcSTT3B缺失的转化体对ER胁迫诱导剂TM更敏感，并且在菌丝体中显示出低糖蛋白含量，表明PcSTT3B与ER应激反应和N-糖基化有关。因此,PcSTT3B参与了开发，致病性，和辣椒假单胞菌的N-糖基化。
