Construction of sll0862 or slr0643 disrupted mutants and their phenotype analysis in Synechocystis sp. PCC6803

Abstract:

Abstract: Recently a novel membrane-associated metalloprotease EGY1 was found to localize in the chloroplast of Arabidospis and is required for chloroplast development and fatty acid biosynthesis. The genes slr0643 and sll0862 from cyanobacteria Synechocystis sp. PCC6803 encode EGY1 homologs. [Objective] For functional characterization of these two genes, [Methods] disrupted mutants slr0643::km and sll0862::km were constructed by homologous recombination. [Results] Under 30 degree, normal light and autotrophic growth, compared with wild type, slr0643::km showed similar growth rate in the early stage, but emitted less photosystem I (PSI) fluorescence under 77K and the activity of the entire photosynthetic electron transfer chain was only 83% of the wild type, while cells contained normal thylakoid membranes. No significant difference was found between sll0862::km and wild type under this condition. [Conclusion] These results indicated that slr0643 was involved in PSI assembly and photosynthesis directly while sll0862 did not affect assembly of PSI and PSII directly at this stage, which lay a foundation for further exploring their function and mechnism in cyanobacteria.

Key words:Keywords：Synechocystis sp. PCC6803;protease EGY1;homologs;slr0643;sll0862;disrupted mutant;77K fluorescence