江苏西葫芦上首次检测到中国南瓜曲叶病毒OA

In the autumn of 2022,it was found that zucchini plants showed suspected viral disease symptoms such as leaf shrinking,deformity and fruit cracking in Pukou,Nanjing,Jiangsu.To identify virus species,the pathogen detection was carried out with universal primers suitable for cucurbitaceae crop viruses.The results showed that all samples were positive in the using the universal primer for geminivirus,and the amplicons shared the highest homology(98.70%)with squash leaf curl China virus(SLCCNV).In order to further confirm virus species,the specific primers against coat protein(V1)gene of SLCCNV were designed for PCR detection,and the target fragments could be amplified from samples.Via cloning and sequencing,it was suggested that V1 gene of Nanjing Pukou isolate(PV361033)was 771 bp in length,and the homology with the isolates of Shandong Shouguang(OM258181),Shandong Zibo(OM258179)and Guangdong Xuwen(MW389919)was 100.00%.Phylogenetic analysis revealed that SLCCNV isolates clustered into two distinct clades,an East Asia-Southeast Asia(EA-SEA)clade and a South Asia(SA)clade,showing significant geographical differences.Within the EA-SEA clade,the isolates from South China showed closer genetic relationships with those from SEA countries,whereas the isolates from East and North China formed a small branch,including Nanjing Pukou isolate.Virus tissue testing showed that SLCCNV widely distributed in zucchini plants,and infected the leaves,flesh,peel and fruit cracking tissues.These results indicate that the virus detected in zucchini from Nanjing was SLCCNV,which is the first report of SLCCNV infected in crops from Jiangsu Province.