Isolation Of GhCYP1 Gene And Its Functional Analysis Of Tolerance To Salinity And Pathogen Stresses In Upland Cotton

Cotton (Gossypium hirsutum L.) is one of the most important economic crops, which is tolerant to middle salt level stress. However, with the growing seriousness of soil salinization and increased demand of fiber, the high concentration of salt saline is becoming to be the main factor to restrict cotton production. Therefore, how to exploit and use saline land has becomed to be one of the most important measures to ensure the yield and production of cotton. Moreover, it is important to isolate and identify some key salt-tolerant genes for further breeding new cotton cultivars and improving the adaptability of cotton to saline land.Plant cyclophilin (CyPs) genes are a class of functional genes, which were found to be correlated with the regulation of plant development and participated in the process of plant response to a variety of biotic and abiotic stresses. In this study, based on the EST sequences of salt-tolerant relative genes by employing SSH-PCR technique, we isolated and cloned a Cyclophilin-like gene GhCYP1 from cotton (Gossypium hirsutum L.), as well as made some functional analysis about its tolerance to salt and pathogen stresses in order to enhance cotton tolerance to salt and pathogen stresses, so as to provide more available germplasm resources for developing salt and disease tolerant transgenic lines and breeding of cotton. The results are as follows:1. Using rapid amplification of cDNA ends (RACE) reaction, a full length 801 bp cDNA of Cyclophilin-like gene was cloned from cotton (Gossypium hirsutum), which containing a 522 bp coding sequence (CDS), and was designated as GhCYP1. Amino acid sequence alignment analysis showed that the GhCYP1 was highly identitied with cyclophilins from Arabidopsis thaliana, Oryza sativa and Homo sapiens.2. By Semi-quantitative PCR experiments, the expression pattern analysis showed that the cotton GhCYP1 was found with constitutive expression in the root, stem and leaf tissues, and the expression level in root and stem was higher than in leaf.3. The GhCYP1 gene was respectively transformed into tobacco and cotton mediated by Agrobacterium transformation. The analysis of salt-stress treatment showed that the growth of transgenic tobacco seedlings was normal, however, non-transformed control exhibited dwarf, necrosis, and decoloration on 1/2 MS medium containing 150 mmol/L NaCl; After 40 days treatment of high temperature and salt stress, the leaves of non-transformed control was almost off and no seed was harvested, while the leaf loss of transgenic cotton was little, and a small amount of seeds was obtained. Finally, seven transgenic lines with high tolerance to salinity were selected.4. Inoculating transgenic and non-transgenic tobacco plants with Pseudomonas syringae pv tabaci (Pst), according to the bacterium growth curve and the damage symptom of leaves post inoculation, we found that overexpression of GhCYP1 gene of transgenic tobacco can enhance tolerance to Pst possibly due to it can suppress the growth of Pst, thereby, exhibited delaying damage symptom.