Molecular Identification and Variation Analysis of Terminal Region for TMV and PVY Isolates from Fujian

To accurately and timely identify viral pathogens and track variation and epidemic trend of viral diseases,specific primers were used in RT-PCR,by which TMV and PVY were identified respectively from infected tobacco leaves collected from Fujian Province.The results of viral sequence analysis showed that the amplification products were the 5'terminal region of TMV and the 3'terminal region of PVY with sequence lengths of 959 and 646 nt respectively,both including of terminal noncoding region and part of the coding region of viral functional genetic protein.Comparing the obtained terminal sequence with the same regions of the viral isolates in NCBI revealed that the noncoding region of 5'terminal end of TMV was highly conservative,N terminal coding region of some of 126kDa or 183kDa protein among different TMV isolates presented some variations (mutations).In terms of numerical differences of variation,the difference between CP coding region and 3'terminal region of PVY was not apparent.The variations (mutations) mainly came from base conversion.Natural selection pressures affected virus genome variation (mutation) to a certain degree.