Detection And Molecular Identification Of Geminiviruses In Four Regions Of China

Geminiviruses are a group of viruses with single-stranded circular DNA and have causeddevastating damage to some economically important crops all around the world. In order to have abetter understanding of the species, distribution and occurrence regularity of viruses discovered inHenan Province, Hebei Province, Tianjin Municipality and Xinjiang Uygur Autonomous Region,samples from these regions were detected and identified.52tomato samples collected from Henan Province, Hebei Province and Tianjin Municipality weredetected by PCR technique with one primer pair which was designed according to some reportedsequences of geminiviruses. The results showed that the800bp specific DNA segments were amplifiedfrom50samples and the infection ratio was96.2%. By DNA sequencing technique, the777bpcomplete CP gene sequences of44isolates were obtained.Sequence comparison showed that sequenceidentity between these CP sequences was99.45%. Using BLAST programme in the GenBank databaseto perform similar retrieval, we found that the isolates which shared high sequence identity with theseCP sequences were Tomato yellow leaf curl virus (TYLCV) isolates. Their sequence identities withreported TYLCV isolates SH2(AM282874), HNSQ(JF414237), HBBD(JN990922), SD2A-7(GU199587), ZJ6(AM698118) and AH-HB1(FN650807) were above99%. It can be preliminarilyinferred that these tomato samples were infected by TYLCV.In the year of2012, yellow and curl symptoms had been observed on tomato, pepper, eggplant,datura, poinsettia, cyclamen and anthurium in Kashi Prefecture, Turpan Prefecture and Ili KazakhAutonomous Prefecture of Xinjiang Uygur Autonomous Region. The results showed that all the above7species of plants could be infected by Begomovirus. Eight genome sequences of the isolates wereobtained: KSCTo4, KSCTo16, KZPTo18and KYCTo20from tomato, KSCPe6and KSCPe7frompepper, KSCEg1from eggplant and KSCDa from datura. Each isolate had all the characteristic featuresof Begomovirus genome organization. There were no big differences between sequences isolated fromdifferent hosts in this experiment. Pairwise comparisons of the eight sequences indicated that thesequence identities were99.0%～99.8%. And their sequence identity with reported isolates SH3(FN256258), ZJ6(AM698118), SD2A-7(GU199587), HNSQ(JF414237) and HBBD (JN990922) ofTYLCV from other regions of China were98.6%～99.5%. It is the first report of TYLCV infection inXinjiang Uygur Autonomous Region, and also the first report of TYLCV infection of eggplant,cyclamen and anthurium.The DNA extract of one pepper sample collected from Ili Kazakh Autonomous Prefecture ofXinjiang Uygur Autonomous Region was detected by PCR technique and only partial sequence ofTYLCV was obtained. However, if rolling circle amplification and enzyme digestion treatment weredone for the DNA extract before PCR amplification with universal primer AV949/CoPR, PA/PB andSSPF1/SSPR1pairs, cloning and sequencing, A1sequence(419bp), A2sequence(509bp), P sequence(670bp) and S sequence(925bp) could be obtained. Using BLAST programme in theGenBank database to perform similar retrieval, we found that A1sequence had high sequence identitywith other TYLCV isolates, A2sequence and P sequence had high sequence identity with Papaya leafcurl China virus (PaLCuCNV) isolates and its sequence identity with PaLCuCNV isolatesHeZM1(FN256260), ZX89(JX128102) and ZM1(EU874386) were above97%and S sequence had highsequence identity with Beet curly top Iran virus(BCTIV) isolates and its sequence identity withBCTIVYazd(EU273816), IR: Kam: B24K: Sug:08(JQ707943), IR: Kam: B22K: Sug:08(JQ707941),IR: Kam: B19K: Sug:04(JQ707940) and [K](EU273818) were85%. There are no reports of BCTIV inChina before.