土传黄瓜立枯病高效拮抗菌的筛选鉴定及其生物效应

采用平板对峙法从黄瓜根际土壤中分离出的400余株细菌菌株中筛选出16株对立枯丝核菌Rhizoctonia solani具有拮抗效果的菌株,抑菌带直径在0.81～1.93 cm之间。并从中选出3株抑菌带直径在1.6cm以上的菌株N33、N35和N43,结合形态、生理生化特性及16S rDNA序列比对分析,鉴定N33菌株为假单胞菌属Pseudomonas sp.,N35和N43菌株为芽胞杆菌属Bacillus sp.。通过在黄瓜育苗基质中添加选育的高效拮抗菌株,观测其对黄瓜苗生长的促进作用以及对立枯病的防治作用,3株菌株均具有促进黄瓜苗期生长和防治苗期立枯病的作用,其中N43菌株促生及防病效果均最显著,地上部鲜重比对照处理增加62.16%,防治效果达62%。

Screening and identifying antagonistic bacteria against Rhizoctonia solani and their biological control effects on soil-born damping-off disease of cucumber

In this study, more than 400 bacterial strains were isolated from rhizosphere soil of cucumber, and the dual culture method was used to screen bacterial antagonists against Rhizoctonia solani. Sixteen strains of bacterial antagonists were isolated and their inhabiting zone against R.solani ranged from 0.81 cm to 1.93 cm. Based on the results of morphologic characteristics, physiological and biochemical properties and phylogenetic analysis of 16S rDNA, three strains (N33, N34 and N43) with inhabiting zone more than 1.6 cm were identified as Pseudomonas sp, Bacillus sp. and Bacillus sp., respectively. Through application of the three antagonists in cropping substrate of cucumber seedlings, their promotion effect on cucumber seedlings and control efficiency on damping-off disease were tested. All of the three isolates could promote the growth of cucumber seedlings and suppress cucumber seedlings from damping-off disease. Among of them, N43 showed the best effect on increasing the fresh weight of shoot by 62.16% and preventing the disease with a control efficiency of 62%, compared with control.