AUTHOR=Sun Tao , Xu Le , Wu Lina , Song Zhongdi , Chen Lei , Zhang Weiwen 

TITLE=Identification of a New Target slr0946 of the Response Regulator Sll0649 Involving Cadmium Tolerance in Synechocystis sp. PCC 6803

JOURNAL=Frontiers in Microbiology

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2017.01582

DOI=10.3389/fmicb.2017.01582

ISSN=1664-302X

ABSTRACT=<p>Survival of photosynthetic cyanobacteria is challenged by environmental contaminations like heavy metals. Among them, deciphering the regulatory mechanisms for cadmium (Cd) in cyanobacteria would facilitate the construction of Cd-resistant strains. In this study, the DNA-Affinity-Purified-chromatin immunoprecipitation assay was employed to identify the direct targets of Sll0649, which was a Cd<sup>2+</sup>-related response regulator identified in our previous work in model cyanobacteria <italic>Synechocystis</italic> sp. PCC 6803. As a result, the promoter region of <italic>slr0946</italic> encoding the arsenate reductase was enriched fourfolds by quantitative real time PCR analysis. Further, deletion of <italic>slr0946</italic> led to a sensitive phenotype to Cd<sup>2+</sup> stress compared with the wild type (WT) and the sensitive phenotype of Δ<italic>slr0946</italic> could be rescued by complementation assay via introducing <italic>slr0946</italic> back into Δ<italic>slr0946</italic>. Finally, individually overexpression of <italic>slr0946</italic> as well as two Cd<sup>2+</sup>-related genes identified priviously (i.e., <italic>sll1598</italic> and <italic>slr0798</italic>) in WT could significantly improve the tolerance of <italic>Synechocystis</italic> sp. PCC 6803 to Cd<sup>2+</sup>. This study provided a better understanding of the tolerance mechanism to Cd<sup>2+</sup> in cyanobacteria and also feasible strategies for tolerance modifications to heavy metals in the future.</p>