生防拮抗菌JK-JS8是一株从松枯梢病叶上分离的对松枯梢病菌具有良好抑制作用的解淀粉芽孢杆菌。为研究该生防菌在植株体内的定殖动态,采用逐步提高诱导浓度的方法,筛选获得稳定的抗性(抗利福平,浓度为100μg/mL)菌株K-8,跟踪分析了K-8菌株在松针、松梢上的定殖差异,以及不同因素(温度、浓度、湿度、喷施期等)条件下的定殖规律,结果表明: K-8菌株在离体和活体松树的表面和内部均可定殖,其中离体表面的定殖效果最好; K-8菌株的定殖能力与宿主、病原菌、 K-8菌株浓度、温度、湿度、喷时期具有相关性;在一定的温度范围内,温度愈高,K-8菌株定殖能力愈强,稳定性越好;喷施的浓度越高,定殖时间越长;在中湿度(50%~70%)范围内更有利于K-8菌株的定殖,高湿度反而不利于其定殖;当病原菌在叶面尚未定殖时有利于生防菌的定殖;在培养液中加入少量松针,更可提高其定殖能力。
JK-JS8 is a biocontrol bacteria that was isolated from pinus leaves infected with Sphaeropsis sap-inea.It is identified as Bacillus amyloliquefacien that has high inhibition on Sphaeropsis sapinea.In order to study the colonization characteristics of JK -JS8 inside the plant , a bacterial strain K-8 with stable antibiotic antibiotic characteristic was prepared , whose colonization difference on pine needle and pine tip as well as the colonization rule on different factors such as temperature , concentration , humidity and spraying period was traced .It was found that K-8 strain could be colonized in the surface or interior of pine in vitro and in vivo , while the best colonization effect was on the surface in vitro .Besides , the colonization ability of K -8 strain was correlated with the host , pathogenic bacteria , concentration , temperature , humidity and spraying time .In a certain temperature range , a higher temperature is conducive to the stronger colonization ability and stability .A higher spraying concentration will help to lengthen the colonization time .A medium humidity within the range of 50% ~70%is more benefits the colonization of K-8 strain.The biocontrol bacteria will be easily colonized when pathogenic bacteria has not been colonized on the leaf surface .A few number of pine needles in the nutrient solution will improve its coloniza-tion.