Objective Cold shock proteins (CSPs) exist in prokaryotes and eukaryotes and can participate in cold, drought and salt stress. However, the role of CSPs in Populus euphratica is not well understood under abiotic stress. The paper aims to further reveal the physiological and molecular mechanisms of plant salt tolerance by studying the role of P. euphratica PeCSP1 in plant salt tolerance.
Method Referring to the NCBI database information, primer5 was used to design primers, Mega7 software was used for multiplex sequence alignment and evolutionary tree analysis, and quantitative PCR was used to detect gene expression. The transgenic lines PeCSP1 (OE1, OE2), wild type and vector control were used as materials, and the response mechanism of PeCSP1 in salt stress was studied from the perspectives of physiology, biochemistry and molecular biology.
Result The P. euphratica PeCSP1 was homologous to CSP1 of Populus trichocrapa. PeCSP1 gene in leaves of P. euphratica was down-regulated under short-term salt stress. The decrease of seed germination rate and root length of PeCSP1-overexpressed Arabidopsis thaliana were higher than those of wild-type (WT) and vector control (VC) after NaCl treatment (75, 100, 125 mmol/L), and the content of Na+ in roots of transgenic A. thaliana was significantly higher than that of WT and VC after salt treatment. Under salt stress, the activity of SOD, POD and CAT was significantly increased in WT and VC, but the salt stimulation of antioxidant enzymes was much less pronounced in OE1 and OE2. After 12 d of salt treatment, the maximum photoquantum efficiency (Fv/Fm) was not decreased in soil-cultured seedlings of OE1 and OE2, but relative electron transfer rate (ETR), actual photosynthetic quantum yield (ΦPSⅡ) and chlorophyll content of transgenic lines showed a high reduction than WT and VC.
Conclusion Overexpression of P. euphratica PeCSP1 negatively regulates the salt tolerance of A. thaliana.
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