Study On The Regulatory Mechanism Of The Gene Slr0280 From Synechocystis Sp. Pcc6803

With the development of molecular biology and molecular genetics, especially DNA recombinant, the cyanobacteria molecular genetics makes a great progress in modern biotechnology. Synechocystis sp. PCC6803 is a unicellular cyanobacterium that is to grow autotrophically using light energy or heterotrophically on glucose, can be naturally transformed by exogenous DNA. It is one of the research model species for genetic and molecular studies of cyanobacteria.In this study, the slr0280 gene of unknown function in cyanobacterial was amplified by PCR. The resulting slr0280 fragment was cloned in plasmid pBluescript SK(+) to generate plasmid pBlue-slr0280. The whole fragment with the slr0280 DNA was deleted and replaced by a kanamycin resistance cassette to generate plasmid pBlue- slr0280--Kan, which was used to transform the Synechocystis sp. PCC6803 wild-type strain and a mutant with resistance to kanamycin was obtained. PCR analysis of the genomic DNA from the resulting mutant indicated that the appropriate deletion and insertion indeed had occurred.We had studied the mutant from the physiological curve, the content of phycobiliprotein and chlorophyll a, the light intensity, exogenous glucose, salt concentration gradient on the growth of algae and the assay of absorption and fluorescence spectrum under room temperature and low temperature. Compared to the wild-type, the mutant-type grew slower, phycobiliproteins, chlorophyll a contained in the mutant-type are less than the wild-type, which suggested that the photosynthesis efficiency in the 0280- strain was lower than that of the wild-type strain. In the presence of exogenous glucose conditions, the 0280- strain grew better than the wild-type strain, which indicated that the mutant was more suitable for the mixotrophic condition. Low-temperature fluorescence spectra show that slr0280 gene deleted did not cause a great impact on the energy transfer process of the photosynthetic. And its function need to be further studied.