Control Effects Of Trametes Versicolor Dextran On Wheat Yellow Dwarf And Screening Of Plants Endogenous Actinomycetes

Wheat yellow dwarf is caused by Barley yellow dwarf virus(BYDV), one of the most important virus disease of wheat and commonly known as yellow plague or wheat cancer. Trametes versicolor dextran extracted from mycelium or fruiting body of Trametes versicolor, has the antiviral, antioxidation, antitumor, hpyerglycemic effect and immune regulation et al. bioactivity. So this study used Trametes versicolor dextran to control Wheat yellow dwarf firstly and develop a neotype plant virus immune regulator—1.1% Trametes versicolor dextran agent.In order to evaluate the preventive and therapeutic effect of 1.1% Trametes versicolor dextran on wheat yellow dwarf caused by Barley Yellow Dwarf Virus, we arranged green house prevention, therapy and field prevention tests. In addition, we determined the activity value of wheat defensive enzymes to discuss the mechanism of the dextran preliminary.The green house experiment showed that preventive efficacy of Trametes versicolor dextran 100、300、500、700、900 times solution were better than therapeutic efficacy. In addition, the preventive and therapeutic efficacy of 100、300、500 times solution were all above 50%, and 100 times solution was best which reached up to 66.67%、61.25%. The result showed that certain concentrations of Trametes versicolor dextran had effective treatment to BYDV especially sprayed dextran in advance.Field prevention tests showed that 1.1% Trametes versicolor dextran 100、300、500 times solution all had significant difference from 20% Virus A WP 500 times and 8% Ningnanmycin SL 300 times in preventive efficacy to BYDV. The preventive efficacy of the 100 and 300 times solution was best, which reached up to 58.63%、57.59% and no significant difference was seen between them. The output effort of 1.1% Trametes versicolor dextran 100、300、500 times solution reach to 22.91%、22.57%, which compared with contrast agents had significant difference and also the production of wheat increased by more than 10%. The result showed that Trametes versicolor dextran also had preventive effect on BYDV in field and the preventive efficacy and output effort of 100 and 300 times solution were much better. So Trametes versicolor dextran is expected to be developed a neotype plant virus immune regulator.The activity of defensive enzymes determination showed that different treatments all could induce wheat defense enzymes activity increased in varying degree and slowed down after reaching a certain peak. Trametes versicolor dextran plus BYDV could induce the activity of wheat defensive enzymes increased significantly and quickly. The peak value time of β-1,3 glucanase, chitinase and phenylalanine ammonia-lyase all reached at the 5, 3 and 7 days and the activity value respectively was 4.95, 1.73 and 1.93 times as that of CK. Enzymes activity slow declined after reached the peak, but still at a higher level. The result showed that the dextran could induce the activity of wheat defensive enzymes increased quickly and significantly to resist diseases.In addition, this study isolated plants endogenous actinomycetes from cucumber, tomato, Chinese cabbage, cabbage of greenhouse vegetables and used confronting incubation on PDA plates method screened an antagonistic actinomyces strain yhy-1. The results of antagonistic activities showed that the strain yhy-1 displayed a broad-spectrum inhibiting activity to all the 8 plant pathogenic fungi tested. Especially, the inhibition rate out to 44% ~ 63% was presented by the strain against 5 ones of the pathogens, Botrytis cinerea、Corynespora cassiicola、Colletotrichum capsici、Alternaria solani、Fusarium graminearum. According to the characteristics of morphological, physiological and biochemical as well as 16 S rDNA sequence, the strain yhy-1 was identified as Streptomyces sindenensis.