水稻白叶枯病菌单细胞系毒力分化研究

 以稀释倒平板法从0型菌086和IV型菌967-4和9620中分离到59个单细胞系;在12个近等基因系品种上,086和其单细胞系表现为弱毒力,2个IV型菌及其单细胞系能克服抗病基因Xa-1、2、3、8、10、11、14的抗性,不能克服Xa-21、4、5、7、13的抗性;带主效抗病基因的品种Asominori、XM5、M41、XM6和丰锦能把3个母株的59个单细胞系区分为12种数量差异或质量差异的不同致病型;将此5品种与近等基因系配合,适合作为病菌致病基因变异频度监测的寄主;采用"段叶沙培,切口取菌胶"法分离病菌,在中国致病型鉴定品种上划分的致病型,是田间病菌群体毒力结构的表型反应。

VIRULENT DIFFERENTIATION OF MONO-CELL CLONES OF Xanthomonas oryzae pv. oryzae

Fifty nine mono cell clones(MCC) were isolated from pathotype 0 (the strain 086) and IV (the strains 967 4 and 9620) by placing their suspensions of 10 -7 ,10 -8 ,10 -9 dilution series on Petri dishes with EDTA PSA. The strain 086 and all of its MCC showed weak virulence, but strains 967 4 and 9620 and their 39 MCC could overcome the resistance to bacterial leaf blight of rice controlled by the resistant genes Xa 1,2,3,8,10,11 and 14, but could not overcome the one controlled by Xa 21,4,5,7 and 13, when they were inoculated on the leaves of the near isogenic lines (NIL) consisting of 12 varieties by a clipping methods. On the 5 varieties with dominant genes, Asominori,XM5,XM6,M41 and Feng jin, the virulence of IV strains and their MCC was classified into 12 pathotypes with quantitative or qualitative differentiations. Therefore, it was suitable for surveying the variant frequencies of pathogenetic genes of X. o. pv. oryzae that the NIL plus the 5 varieties was used as differentials. However, the pathotype of the field population of X. o. pv. oryzae identified using the China pathotype differentials (CPD) such as Jg30,Tetep,Nj15,Java14 and IR26 with the strains isolated by picking up the bacterial oozes from the top of cutting lines ofdiseased leaf sections plunged in the sand with water were actually the reactions of natural virulent compositions of phenotypes in fields.