Cloning and sequence analysis of coat protein gene of Cucumber mosaic virus under low temperature stress
Aiming at studying CMV coat protein gene sequence variation and further analysis the evolutionary mechanism of plant RNA viruses upon low temperature stress,tobacco(Nicotiana tabacum var.Samsun NN) in-fected with cucumber mosaic virus isolate(CMV-BG) was planted under room temperature and low temperature for 30 d,and then the CMV cp gene was cloned and its sequence and polymorphism were analyzed.The results showed that cp gene polymorphism(Pi=0.001 76) in low-temperature group was higher than that in normal temperature group(Pi=0.001 14),and the 48th amino acid site was a positive selection site in low-temperature group,detected by IFEL.It showed that low temperature stress can improve the CMV-BG cp gene polymorphism,and it is an important force for gene sequence evolution of RNA viruses during the interaction between the host and the virus.