Diversity Of DsRNA From Botryosphaeria Dothidea Fungal Viruses

Botryosphaeria dothidea is the causal pathogen of canker disease in forest and fruit trees, and is widely distributed all over the world, it seriously affected the health and caused loss of forest and fruit trees. The mainly management measures were integrated control which applied combining with plant quarantine, resistant varieties, and forestation technique measures and chemical control. Because the effect of integrated control is unsatisfactory, finding a new strategy to control the disease is the important issue. People are paying more and more attention to biological control because of its persistence and environmental safety.Mycoviruses are widespread in all major groups of plant pathogenic fungi. There is convincing evidence that mycoviruses are responsible for debilitation or hypovirulence phenotypes in some pathogenic fungi. From agricultural perspectives, mycoviruses may contribute to sustainable agriculture as biological control agents. Extracting dsRNA virus from B. dothidea to control canker disease in forest and fruit trees are very important. This study mainly explores the diversity of dsRNA fungal viruses from B. dothidea, the differences in culture characteristics, the mycelia growth rate and transmission stability of34B. dothidea isolates collected from the Bohai bay after establishing the dsRNA extraction system. The main results are as follows:1. Establishing the dsRNA extraction method of B.dothideaSelecting the strains of sdaull-119and sdaul2-60. Using Tris-saturated phenol and water-saturated phenol to extract the dsRNA of test strains, respectively. The result showed that Tris-saturated phenol dsRNA extraction method is developed in B.dothidea.2. Testing the diversity of dsRNA fungal viruses from B.dothideaThe mycoviruses are found in7strains after extracting dsRNA from34B.dothidea isolates, the existence rate is20.59%. Experiments show that dsRNA in B.dothidea do not exist in all strains. We can find the diversity of dsRNA fungal viruses from7B.dothidea strains through the agarose gel electrophoresis, and the dsRNA observed in7strains was different kind of virus.We found two sequences from sdaul2-60,after BLAST searches of the nucleotide sequences, we propose that the two dsRNAs are the genomic components of BdPV1.We found one sequence from sdaul1-119,after BLAST searches of the nucleotide sequences,we propose that the one dsRNA is the genomic components of a victorivirus designated as BdVVl. This is the first report of a parititivirus and a victorivirus infecting B. dothidea, respectively.3. Comparising cultural characters and virulence differentiation between viral and the non-viral strains of B. dothidea strainsAccording to the cultural characters, growing rated and virulence, we can see there is no obvious correlation between the viral strains and non viral strains. Different strains have different characteristics.4. Exploring the stabilit of different isolates carried viruses in different generationsIn this study, the detoxification of fifth generation in sdaul2-60and sdau11-119were subjected to agarose gel electrophoresis. The same dsRNA segments in the isolates obtained from hyphal tip of sdaul2-60and sdau11-119. It is mean the dsRNA virus in B. dothidea existence stably.