不同种类的细菌对大白菜软腐欧氏杆菌根表吸附的竞争作用

用吸附竞争试验,测定了8种细菌共10个菌株对大白菜软腐欧氏杆菌(Erwinia carotovorasubsp.carotovora)菌株 RL4在大白菜根表吸附的竞争作用。竞争菌的吸附竞争作用与它们对大白菜根表的吸附能力相一致,在等量混合接种时,只有能对大白菜根表发生吸附的7个菌株表现出程度不同的吸附竞争能力,其中以菌株 BCE 4(RL 4是从它筛选出的抗利福平菌株)竞争最强,它也是对寄主根表吸附能力最强的菌株,其吸附竞争作用最高可达98%,不表现1∶1的数量关系。RL4和 BCE4的热杀死菌体不发生吸附竞争。发生吸附竞争的有效时间为竞争菌对根表预吸附15分钟以后,或病菌(RL4)吸附15分钟以前。

COMPETITIVE INHIBITION BY DIFFERENT SPECIES OF BACTERIA IN ABSORPTION OF SOFT ROT ERWINIA ON CHINESE CABBAGE ROOTS

The competitive inhibition of absorption of the soft rot erwiniastrain RL4 on root surfaces of chinese cabbage wastested with 10 compe-tition strains of 8 species of bacteria,including Erwinia carotovora subsp.atroseptica strain E1562,E.carotovora subsp,carotovora BCE4 and itscolony mutant Se-24,E.chrysanthemi RSZ-9,Xanthomonas campestris pv.campestris Xcc-D,Pseudomonas syringae BPS-5,P.avenae OPA-D,P. fluorescens RN-1,Bacillus subtilis BW-1,and Escherichia coli Eco-D.RL4 is a rifimpicin (?)esistant strain selected from Ecc BCE4.Results in-dicated that the effects of absorption competition of these competitorswere dependent on their ability of absorption to root surfaces of theplant,When inoculation of plant roots was made with combined inoculasuspensions containing equal amount(1:1)of the pathogen and com-petitors,no competition was given by the strains BW-1,BPS-5,andOPA-D,which were unable to absorbe to the plant,whereas 12%-98%effects of absorption competition were reached by the other 7 strains,which showed 24%-238% absorption to the plant as comparing with thestrain RL4,The strain BCE4 expressed the highest compatibility in bothabsorption and absorption competition.When the suspension was madeas 1:10~4 radio of inocula of BCE4 to RL4 and used to inoculate theroots,the more than 60% competitive effect was obtained,which didnot follow the cell-competition effect in 1:1 radio of these combinedinocula.The absorption competition took place only by 15 minuts beforethe pathogen was absorbed or after the competitors were absorbed to theplant roots,The neat-killed cells of RL4 and BCE4 were unable tocompete with the alive cells of RL4 for absorption on the roots of chinesecabbage.