Department of Biochemistry and Molecular Biology, Faculty of Science, Saitama University, Saitama, Japan.
Department of Biological Sciences, Graduate school of Science, Tokyo Metropolitan University, Tokyo, Japan.
Environ Microbiol. 2022 Nov;24(11):5165-5173. doi: 10.1111/1462-2920.16162. Epub 2022 Aug 23.
The cyanobacterium Anabaena sp. strain PCC 7120 exhibits dehydration tolerance. The regulation of gene expression in response to dehydration is crucial for the acquisition of dehydration tolerance, but the molecular mechanisms underlying dehydration responses remain unknown. In this study, the functions of the response regulator OrrA in the regulation of salt and dehydration responses were investigated. Disruption of orrA abolished or diminished the induction of hundreds of genes in response to salt stress and dehydration. Thus, OrrA is a principal regulator of both stress responses. In particular, OrrA plays a crucial role in dehydration tolerance because an orrA disruptant completely lost the ability to regrow after dehydration. Moreover, in the OrrA regulon, avaKa encoding a protein of unknown function was revealed to be indispensable for dehydration tolerance. OrrA and AvaK are conserved among the terrestrial cyanobacteria, suggesting their conserved functions in dehydration tolerance in cyanobacteria.
集胞藻 PCC 7120 表现出脱水耐性。基因表达的调控对获得脱水耐性至关重要，但脱水响应的分子机制仍不清楚。在这项研究中，研究了响应调节剂 OrrA 在盐和脱水响应调节中的功能。OrrA 的缺失或破坏消除了数百个基因对盐胁迫和脱水的诱导。因此，OrrA 是两种应激反应的主要调节剂。特别是，OrrA 在脱水耐性中起着关键作用，因为一个 OrrA 突变体在脱水后完全丧失了再生长的能力。此外，在 OrrA 调控基因中，编码一个未知功能蛋白的 avaKa 被揭示对脱水耐性是不可或缺的。OrrA 和 AvaK 在陆生蓝藻中是保守的，这表明它们在蓝藻的脱水耐性中具有保守的功能。
