Detection And Sequence Diversity Analysis Of Viroids Isolated From Several Perennial Plants In China

RNA was extracted from 67 grapevine samples, which were collected from Beijing, Shenyang, and Xinjiang, 5 apple samples from Liaoning and Xinjiang, and 11 coleus samples from Beijing. Then the samples were detected by dot blot hybridization, return-PAGE, and RT-PCR. The results showed that (1) no viroid was detected in G59-G65 (from Shenyang);Hop stunt viroid (HSVd) were detected in 41 samples G1-G58;Grapevine yellow speckle viroid (GYSVd) in 29 samples, and both viroids were found in 23 samples among the grapevine samples from Beijing;HSVd and GYSVd were detected in samples G66 and G67, Australia grapevine viroid (AGVd) in G66;Citrus exocortis viroid (CEVd) were not detected in all the grapevine samples. (2) Apple scar skin viroid (ASSVd) was detected in apple samples A1, A3, and A4. (3) Coleus blumei viroid (CBVd) was detected in all the coleus samples.Some positve samples were purified and then amplified by reverse transcription - polymerase chain reaction (RT-PCR). The RT-PCR product was cloned into the vector and sequenced. The results showed that (1) there have little base mutation in AGVd, HSVd sequences,but much mutation in GYSVd In the study on GYSVd, a new viroid was found in grapevine sample G66, named Chinese grapevine viroid (CGVd), which has less man 90% similarity to GYSVdl and GYSVd2. (2) the sequences of ASSVd Liaoning isolate and Xinjiang isolate have a top similarity with the sequences reported by Puchta.. (3) the sequences of CBVd abtained in tins study have a similarity of 8523% ~ 99.20% with other isolates reported hi GenBank.28 HSVd sequences, 18 GYSVd sequences, 7 CGVd sequences, 8 AGVd sequences, 3 ASSVd sequences, and 5 CBVd1 sequences were deposited into GenBank. And it is the first report about HSVd, AGVd, GYSVd1, and GYSVd2 in China.