Preparation Of Protoplast Of Rice Sheath Blight Fungi And Study On Biological Characterization Of Regenerants

Rhizoctonia solani(teleomorph,Thanatephorus cucumeris ) and Rhizoctonia oryzae-sativae(teleomorph,Ceratobasidium oryzae-sativae) could infect rice and lead to rice sheath blight disease.The study of molecular biology of Rhizoctonia spp was relatively under-develeped because of no basidiospore and conidium produced and short of efficiency genetically transformation system.In this rsearch,Rhizoctonia solani WH-1, Rhizoctonia oryzae-sativae WH-87,and strain RCOL including rDNA of C. oryzae-sativae and T.cucumeris,were studied to understand the process of protoplast isolation and regeneraion,and to supply materials for genetically transformation system of these fungi.Regeneration rate could be up to 65%when mycelium of WH-1 cultured for 15 h at 28℃,120rpm in PDB were treated by 1.5%Lysing enzyme at 30℃for 150 min and cultured on RM.regeneration rate could be up to 32.6%and 2%when mycelium of WH-87 and RCOL cultured for 24 h at 28℃,120rpm in PDB were treated by 2.0% Lysing enzyme at 30℃for 150min and cultured on RM.40 regenrants were obtained from strain WH-1.There was no difference in colony morphology and karyotype between regenrants and strain WH-1.Growth rate of 27 regenerants were higher than that of strain WH-1 and there existed significant difference on pathogenicity among regenrants.140 regenerants were obtained from strain WH-87.The regenerants were seperated into TypeⅠ(88.6%),and TypeⅡ(11.4%) based on colony mophology.Growth rate of 50 regenerants were tested,the growth rate of TypeⅠregenerants was much higher than that of strain WH-87 and regenerants of TypeⅡ.There existed significant difference in pathogenicity and no difference in karyotype between regenerants and strain WH-87.82 rengenrants were obtained from strain RCOL.The regenerants were seperated into TypeⅠ(61.1%),TypeⅡ(13%),and TypeⅢ(15.9%) based on colony mophology. There existed significant difference in pathogenicity and no difference in karyotype between regenerants and strain RCOL.The results suggested that there was rich genetic diversity in rice sheath blight fungi tested.