| Strawberries(Fragaria Xananassa)belong to the genus Fragaria(Fragaria spp.)in the Rosaceae family and are widely grown around the world for their juicy flesh,special aroma and high nutritional and economic value.China is currently the world leader in strawberry cultivation area and production,but strawberry virus disease has become one of the most important factors affecting strawberry production due to its seedling propagation method and transportation.The strawberry vein banding virus(SVBV),strawberry pallidosisassociated virus(SPa V)and strawberry pallidosis-associated virus(SPa V)were identified by small RNA extraction,library construction and highthroughput sequencing from suspected diseased leaves collected in Fuzhou,Fujian Province.associated virus(SPa V)and strawberry mottle virus(SMo V).The full-length genomic sequences of SMo V isolates from Fujian Province were amplified and sequenced by RT-PCR,3’ and 5’ RACE.SMo V genomic RNA1 and RNA2 were 7034 nt and 6354 nt,respectively,and both contained an open reading frame(ORF),encoding polyproteins P1 and P2,respectively.The genomic structure is similar to that of other reported SMo V isolates.Consistency analysis of the SMo V Fujian isolate with the other 15 SMo V isolates showed that the RNA1 nucleotide identity ranged from 79.2% to 96.8%,with the SMo V Fujian isolate showing higher identity with the Chinese isolate at 96.7%-96.8%,and with the Dutch isolate 1134,the Canadian isolates Nsper51 and simcoe,and the Czech isolate SMo V＿,The amino acid identity of polyprotein P1 was89.0%～99.5%,with Chinese isolates DGHY3,DGHY21,BJMX7 and SDHY5,and Canadian isolates NB926,NSper3 and The nucleotide sequence identity of RNA2 and the other 15 SMo V isolates was 77.9%-97.8%,while the identity with the five Chinese isolates was higher.The consistency with the five Chinese isolates was higher at 97.1%-97.8%;the lowest consistency was with the Czech isolate A at 77.9%.Polyprotein P2 amino acids were in agreement with other isolates in the range of 89.9%-98.9%,with higher agreement of 98.0%-98.9% with both the five Chinese isolates and the Czech isolate SMo V＿RNA1＿C;and lower agreement of89.9% with the Dutch isolate 1134.The Fujian isolate and most of the Chinese isolates were found to be geographically related.RNA2,like other published full-length isolates,has a 717-nt sequence encoding 239 amino acids in the C-terminal coding region,which is missing in Dutch isolate1134.A phylogenetic tree was constructed using the polyprotein P2 amino acid sequence of the SMo V Chinese Fujian isolate(Fujian)and 15 other SMo V isolates,with the Fujian isolate clustered on a large branch with the Chinese part of the isolate,and most closely related to the Chinese isolate DGHY3.Two Chinese isolates of SMYEV,FJ1 and FJ2,co-infected with strawberry plants were identified and their whole genome sequences were determined and analysed.ORF1 encodes the viral replicase protein,ORF2,ORF3 and ORF4 encode the three mobile proteins TGBp1,TGBp2 and TGBp3 respectively,and ORF5 encodes the coat protein(CP).The genomic nucleotide sequence identity of the SMYEV isolates FJ1 and FJ2 was 89.8%,and the genomic nucleotide sequence identity of both and other SMYEV isolates was 83.7%-89.8% and 84.1%-90.0%,respectively;phylogenetic analysis based on the CP gene showed that FJ1 and FJ2 belonged to different groups,and they were distantly related,among which FJ1 was most closely related to Chinese isolates sy01 and sy04,Japanese isolate T1 and Korean isolate KNS1,while FJ2 was related to Chinese isolate sy02,a Canadian isolate PEI113＿12 and Japanese RDP4 recombination analysis indicated that both FJ1 and FJ2 were potentially recombinant.In this paper,small RNA sequencing was used to identify strawberry samples,and the genomes of two important viruses on strawberries,SMo V and SMYEV Fujian isolates,were determined and analysed.this study may provide a theoretical basis for the diagnosis and prevention and control of strawberry viruses in China. |
