Study On The Mechanisms Of Freezing Tolerance And Cold Acclimation Capacity Between StCBF1-tansgenic And ScCBF1-tansgenic Arabidopsis

Low temperature is the one of the major environmental factors,causing serious impact on plant growth and development.Plants have stablished the complex effective defense mechanism to reply low temperature in the long-term evolution process.Currently,the most well understood cold signaling pathway is the C-repeat Binding Factor/DRE Binding Factor?CBF/DREB?transcriptional regulatory cascade.Potato is one of the main grain crop and energy crop.But low temperature could make a huge damage to Potato.It is important to study the anti-cold mechanism of Potato and the difference of freezing tolerance and cold acclimation capacity between StCBF gene and Sc CBF gene.In this study,in order to investigate the mechanism of freezing tolerance between StCBF gene and ScCBF gene,we take wild type?WT?and St/ScCBF1-transgenic Arabidopsis as the experiment materials,the bioinformatics of target gene and electrolyte leakage assay?LT50?were analyzed,the growth of seedlings,net photosynthetic rate?Pn?in leaves,the maximal efficiency of PSII photochemistry?Fv/Fm?,reactive oxygen species?ROS?content,malondialdehyde?MDA?content,antioxidant enzyme activity,and the expression of the freezing tolerance response genes were measured.The main results are as follows:?1?The homology between StCBF1 gene and ScCBF1 gene was high,but the analyzing of the bioinformatics of target gene and blasting protein sequence showed that there was a difference in transactivation domain/unknown function domain.?2?StCBF1 gene and ScCBF1 gene all located in the nucleus and they played roles in the nucleus.?3?The survival status of transgenic Arabidopsis was better than WT and the survival status of ScCBF1-transgenic Arabidopsis was better than StCBF1-transgenic Arabidopsis after freezing treatment.?4?LT50 of transgenic Arabidopsis was lower than WT and LT50 of ScCBF1-transgenic Arabidopsis was lower than StCBF1-transgenic Arabidopsis,the decline of LT50 of ScCBF1-transgenic Arabidopsis was more significant than LT50 of StCBF1-transgenic Arabidopsis after low temperature treatment.?5?Low temperature stress decreased the net photosynthetic rate?Pn?.Compared with WT,transgenic Arabidopsis maintained relatively higher photosynthetic rate,and the photosynthetic rate of ScCBF1-transgenic Arabidopsis was higher than StCBF1-transgenic Arabidopsis.?6?Compared with WT,the maxi.mal efficiency of PSII photochemistry?Fv/Fm?of stransgenic Arabidopsis could keep higher;Fv/Fm of ScCBF1-transgenic Arabidopsis was higner than StCBF1-transgenic Arabidopsis after low temperature treatment.?7?Under low temperature stress,the content of H₂O₂ and the production rate of O₂^·-significant increased,but the content of ROS in transgenic Arabidopsis was lower than that in WT.Between two transgenic tomato plants,the accumulation of ROS in ScCBF1-transgenic Arabidopsis was less than that in StCBF1-transgenic Arabidopsis.?8?Compared with WT,transgenic Arabidopsis could keep higher antioxidant enzyme activities and lower membrane lipid peroxidation degree,antioxidant enzyme activities in ScCBF1-transgenic Arabidopsis were higher than those in StCBF1-transgenic Arabidopsis,and membrane lipid peroxidation degree in ScCBF1-transgenic Arabidopsis were lower than those in StCBF1-transgenic Arabidopsis.?9?Compared with WT and ScCBF1-transgenic Arabidopsis,StCBF1-transgenic Arabidopsis plants accumulated more proline.After low temperature treatment,the accumulation of soluble sugar in StCBF1-transgenic Arabidopsis rose,which were consistent with those in ScCBF1-transgenic Arabidopsis.?10?Low temperature stress induced the expression level of CBF transcriptional regulatory cascade related genes.Between two transgenic Arabidopsis,the expression level of cold-regulated genes?COR15a,KIN1,RD29a?in ScCBF1-transgenic Arabidopsis was higher than that in StCBF1-transgenic Arabidopsis.These results suggested that both ScCBF1-transgenic and StCBF1-transgenic Arabidopsis enhanced freezing tolerance,however,the freezing tolerance and cold acclimation capacity of ScCBF1-transgenic Arabidopsis significanty stronger than StCBF1-transgenic Arabidopsis.The difference may be associated with two factors,on the one hand,ScCBF1-transgenic Arabidopsis could keep higher net photosynthetic rate?Pn?,antioxidant enzyme activities and keep lower the accumulation of ROS,membrane lipid peroxidation degree.On the other hand,there were differences in transactivation domain/unknown function domain and the difference in the expression level of cold-regulated?COR15a,KIN1,RD29a?genes.