Rice Ragged Stunt Virus Induced Rice Dwarf And Tillering/Branching Symptom Analysis

Rice ragged stunt virus(rice ragged stunt virus, RRSV) belong to Reoviridae (Reoviridae), Oryzavirus (Oryzavirus), it can be spread by the brown planthopper and causes the disease of rice ragged stunt. In recent years, Fujian, Guangdong and Jiangxi provinces have discovered the disease, mostly sporadic, different years, the incidence of individual farmland up to 80%. Once a large-scale outbreak of the disease, it will seriously affect our rice production. Dwarf and tillering/branching, is the distinguishing feature of the rice ragged stunt disease. miRNA is the important regulatory factor for a plant growth and development,now the researches show that the miR156 gene families and their target genes have participated in forming the agronomic of rice,including dwarf and tillering/branching. Therefore, this issue use genetic transformation of rice, RNAi, real-time PCR technology and yeast two-hybrid technology to study the miR156 target gene OsSPL and explore RRSV caused dwarf and tillering/branching molecular mechanisms,we obtain the following results:1. The use of real-time PCR technology to detect the expression of rice miR156 target genes’ mRNA in disease and healthy plants at different times after infected by rice ragged stunt virus (RRSV), the results indicate that the expression of susceptible rice OsSPL3, OsSPL4, OsSPL 12, OsSPL14 gene significantly reduced respectively,0.37 times the health of rice,0.41 times,0.2 times and 0.3 times.2. The experiment was constructed OsSPL3, OsSPL4, OsSPL12 overexpression and RNAi vectors using rice genetic transformation system has obtained the corresponding transgenic rice. After analysis of transgenic rice phenotype found positive OsSPL3, OsSPL4 of RNAi transgenic plants and OsSPL3, OsSPL4 plants overexpressing plants compared with the wild symptoms did not appear dwarf,tillering/branching, positive OsSPL 12 overexpressing transgenic rice showed stem slender and tillering/branching less than the wild, other and rice plants showed.There have no significant change with height between the negative symptoms and the wild, The RNAi positive transgenic rice of gene OsSPL12 plants appers a degree of dwarf symptom compared with the wild rice.3. Using yeast two-hybrid analysis to get OsSPL3, OsSPL4 and OsSPL12 did not have interaction with the RRSV. Presumably RRSV with no direct effect of the target gene, presumed the generating of phenotype may be related to the miRl 56 target gene upstream.In summary,Through the observation and analysis to the transgenes of rice,in this paper,we determined that the dwarf symptom has related to the target gene OsSPL12 of miR156 and enhance us to understand the molecular mechanism of the dwarf and tilling/branching symptom caused by virus.