The Optimization Of Expression Condition And Research Of Resistance Mechanism Of RsPrx1 Gene Of Chinese Red Radish In Pichia Pastoris

Peroxidases play various important roles in growth and development of plant. To use transgenic technology to study peroxidases'functions is a subject, which not only serves to understand the function of genes we are insterested in, but also provides the theoretical basis for industrial application of these genes. In ordert to study the diversity and complexity of plant peroxidase biological effects provides a new way of thinking and methods.The present study considered transgenic yeast expressing Radish peroxidase gene RsPrx1 as the object The optimal culture in our study is to add heme (0.5g/L) and microelement mixture(0.5ml/L). In the optimal culture, the ezyme activity of transgenic yeast reached to 30.9U/ml , 5.92 times as much as the common culture. And through SDS-PAGE, there was a significant difference in aim protein. Moreover, we studied the tolerance of transgenic yeast. The results showed: the salt tolerance, antioxidant ability, and high-temperature and low-temperature tolerance of Radish Peroxidase Gene RsPrx1 were stronger in duced-noninduced than Noninduced-induced, particularly strongest in salt tolerance and high-temperature tolerance. This study considered pichia pastoris GSRP25 as the subject investigated and further investigated salinity tolerance. The results revealed that for some physiological and biochemical indicators, such as culture OD600, the activity of POD, protein content and so on, transgenic yeast had more salt tolerance than wild type. From metabolic mechanism's analysis, total RNA is extracted respectively and through RT-PCR screened tolerant genes to determine. The results showed that both HSP12 and CTT1 were expressed, but more in transgenic type than in wild type, which revealed that RsPrx1 played a role in not only protecting yeast from salt stress but also to some extent regulating some antioxidant genes'transcription in yeast making them more expressed to improve salinity tolerance.In conclusion, the present study concentrated on optimizing culture to increase expression of RsPrx1 and more importantly, provided evidences to the functions (salt resistance, antioxidant and temperature resistance) of RsPrx1 and improvement of yeast's sait tolerance.