生防菌R-4的鉴定及其对玉米南方锈病的防效

对分离自玉米植株的内生细菌R-4进行鉴定,测试其对玉米南方锈病(SCR)的防病增产效果。用盆栽方法测定菌株R-4对玉米植株的促生效果,根据16S r DNA序列对菌株R-4进行鉴定,采用自然发病方式测试其对SCR的防病增产效果。结果表明,菌株R-4处理玉米的发芽率、播种后18 d株高、播种后28 d株高、植株地上部干重及根干重比对照分别增加17.19%、32.03%、41.80%、92.53%和37.03%。通过16S r DNA序列分析,将菌株R-4鉴定为蜡样芽孢杆菌(Bacillus cereus)。菌株R-4在先玉335、银糯1号、浚单20上对SCR的防效达39.2%~92.1%(平均为65.7%),经该菌处理后玉米增产2.58%~9.02%(平均为6.66%)。

Identification of Biocontrol Strain R-4 and Its Efficacy in Controlling Southern Corn Rust

A bacterial endophyte R-4 isolated from a maize plant was identified, and its efficacies in controlling southern corn rust(SCR) and enhancing corn yield were tested. Growth promotion effect of strain R-4 was tested by pot culture method. The identification of strain R-4 was carried out based on 16S rDNA sequence analyses. The efficacies of strain R-4 in controlling SCR and enhancing yield were evaluated by observing natural occurrence of the disease on the maize plants tested in the field. In the growth promotion tests, the germination rate of R-4-treated seeds, 18-day-old plant height, 28-day-old plant height, dry weight of above-ground part and dry weight of roots increased by 17.19%, 32.03%, 41.80%, 92.53% and 37.03%, respectively, compared to their respective controls. Strain R4 was identified as Bacillus cereus based on 16S rDNA sequenceanalyses. Strain R4 had a control efficacy of 39.2%-92.1%(av. 65.7%) against SCR on three varieties(Xuanyu335, Yinnuo No.1 and Jundan 20). The yields of the R-4-treated plots increased by 2.58%-9.02%(av. 6.66%).