Detection Of Main Viruses Of Pumpkin In Hunan And Molecular Evolution Of Coat Protein Gene

The origin of the pumpkin is considered to be the continent,one of the earliest cultivated ancient crops.Virus disease is an important disease of pumpkin,due to the growing area of pumpkin cultivation,pumpkin on the disease increased every year,resulting in a sharp decline in the production and quality of pumpkin,while causing greater economic losses,so the pumpkin virus disease has caused people s concern.The four phenotypes of virus infection after pumpkin were shrinkage,mosaic,yellowing and chlorotic.1.Based on the coat protein sequence design of specific primers,224 samples of pumpkin leaf samples taken from Hunan area with obvious symptoms were detected.The main detection of the virus was ZYMV,CCYV,WMV,CMV,PVY and PMMoV,and the positive rates were 36.2%,7.6%,6.7%,2.7%,1.3% and 0.9%,respectively.Single virus infection is the main pumpkin virus disease.The infection rates of ZYMV,CCYV,WMV and CMV were 31.7%,6.3%,3.1% and 1.8% respectively.The infection rate of double virus was 4.4%,among which ZYMV and WMV were susceptible to infection.2.7%;triple virus infection rate of 0.4%.2.The full length of the coat protein of ZYMV,WMV and CCYV was obtained by cloning,sequencing and splicing.Molecular evolution analysis was performed using the sequence data registered on NCBI.3.There was no significant recombination of the three CP genes,and the recombination was not a significant effect of its molecular evolution.ZYMV can clearly divide the three main genealogies according to geographical origin;WMV can be divided into three main lineages;CCVY can divide four main lineages.Mutation and negative selection are the main forces to drive ZYMV,WMV and CCYV evolution.The genetic variation among most isolates was significant,and the population structure was relatively stable in the trend of expansion,and the degree of gene mutation was low.