Detection And Genetic Diversity Of Southern Rice Black-streaked Dwarf Virus In Hunan

Southern rice black-streaked dwarf virus is one of the major virus causing extensive rice losses in China. This study works on two main aspects to study the genetic diversity of SRBSDV hunan isolates. Testing SRBSDV Hunan isolates from different years, different parts to analyze its genetic diversity; Using real-time qPCR to detect the virus load of SRBSDV from different samples.The main results were as follows:(1) Samples in different region of Hunan province from2011to2013were tested,31positive samples were checked out. The full-length the genome segment9(S9), segment10(S10) were cloned and sequenced.The genetic diversity of the genome segment S9,S10of Southern Rice Black-Steaked Dwarf Virus (SRBSDV) were analyzied on symptom, mutations position, phylogenetic analysis and recombination. The homology analysis of5isolates of both ORFs of S9was higher than99.5%. There was3-9mutation positions in both ORFs, nevertheless most of them were nonsense. The results of phylogenetic analysis showed both ORFs from different variants were high level of sequence identity and gathering in same cluster. SRBSDV isolates from single source and the genome diversity of small.(2) SRBSDV content of three kind of rice samples were detected by qPCR. The result shows that SRBSDV content of R1,R2,R3is higher than RO,the highest is R3.The SRBSDV content in different parts of rice is different,the lowest is in root,the highest is in stem. Different regions, different rice varieties, the difference of content of SRBSDV is obvious.