An orphan two-component response regulator Slr1588 involves salt tolerance by directly regulating synthesis of compatible solutes in photosynthetic Synechocystis sp. PCC 6803.

摘要: We report here the characterization of a novel orphan response regulator Slr1588 directly involved in synthesis and transport compatible solutes against salt stress. In Δslr1588 mutant, tolerance was found to be decreased by 2–3-fold. Using high performance Q-EXACTIVE hybrid quadrupole-Orbitrap mass spectrometer, we that proteins glucosylglycerol, key solute, were up-regulated mutant grown 4.0% NaCl, suggesting might function as repressor for glucosylglycerol metabolism. The functional assignment further confirmed using an electrophoretic mobility shift assay (EMSA) showing purified his-tagged could bind vitro upstream regions sll1566 (ggpS) genes required biosynthesis. addition, quantitative proteomic analysis showed biosynthesis another solute Synechocystis, sucrose, also under EMSA bound sll0045 (spsA) gene sucrose Moreover, 113 127 unique up- down-regulated respectively. Notably, dozen transporter study revealed salt-tolerant regulatory mechanism mediated Slr1588, provided description possible regulon Synechocystis.