Cloning and characterization of a salt responsive gene AcPsbQ1 from Atriplex canescens

PsbQ is an extrinsic subunit of the photosystem II in eukaryotic photosynthetic organisms. Numerous studies have demonstrated that PsbQ can stabilize the inorganic cofactors and enhance the oxygen release in PSII. The decrease of photosynthesis rate under salinity condition is normally attributed to the high concentration of injurious ions, such as Na(+) and Cl(-), which accumulate in the chloroplast and damage thylakoid membrane under salinity stress. In this study, AcPsbQ1 was isolated from a halophyte Atriplex canescens cDNA library. The AcPsbQ1 contains an open reading frame of 699 bp encoding a 233 amino acid protein. In order to investigate its function, AcPsbQ1 was cloned and transformed into Saccharomyces cerevisiae INVSc1. The heterologous expression of AcPsbQ1 in transgenic yeast significantly helped to increase the adapting and recovery ability of yeast cells under the salt and drought. Quantitative real-time PCR assay was performed to reveal the expression pattern of AcPsbQ1 under different abiotic stresses. On exposure to NaCl stress, the transcript level of AcPsbQ1 was significantly enhanced. AcPsbQ1 expression level was also up-regulated under drought stress. These results indicated that AcPsbQ1 might involve in the response to salt stress in A. canescens.