松烂皮病内生拮抗细菌的筛选、生防效果及华山松的生理响应

为探究内生细菌对华山松烂皮病的生防效果及其生理响应,采用平板涂布法和对峙培养法从健康华山松树皮上分离筛选抗烂皮病菌Cenangium ferruginosum的拮抗菌株,运用形态学、生理生化及分子生物学对其进行鉴定;并利用喷雾法研究其对华山松苗烂皮病的盆栽防治效果及苗木各生理指标的变化,观测其对田间发病华山松病斑的防治效果.结果显示,分离得到具有优良拮抗效果的菌株Ba4,经鉴定为解淀粉芽胞杆菌Bacillus amyloliquefaciens;其发酵原液盆栽防治效果可达90.15%,稀释至10⁵防治效果也有17.77%,发病率和病情指数均下降.接种病原菌30 d后,不同浓度Ba4菌剂处理的苗木丙二醛含量均减少,木质素、可溶性蛋白和可溶性糖含量均增加;丙二醛含量与发病率和病情指数呈显著正相关,与防治效果呈显著负相关;木质素、可溶性蛋白和可溶性糖含量则与其相反.田间试验中原液和稀释倍液(10、10²和10³)的病斑治愈率均超过80%.表明菌株Ba4对松烂皮病有良好的防治效果,能调节华山松抗性物质的合成.

Screening of endophytic antagonistic bacterium and its biocontrol effect on dieback fungus Cenangium ferruginosum and physiological response of Chinese white pine Pinus armandii

To explore the biocontrol effect of endophytic bacterium on dieback fungus Cenangium ferruginosumand the physiological response of Chinese white pine Pinus armandii, the antagonistic bacterial strain against C.ferruginosum was isolated and screened from the healthy bark of P.armandii by using spread-plate method and confrontation culture method, and was identified based on its morphologial, physiology-biochemistry, and molecular biological characteristics. The control effect of P.armandii seedling dieback and the changes of the physiological indexes were determined by spraying method in pot testing. The efficacy on the spots of diseased P.armandii was observed in the field. The results showed that a strain (Ba4) with excellent effect was obtained, and was identified as Bacillus amyloliquefaciens. The control effect of original fermentation solution reached 90.15% in the pot experiment, and the effect of the diluent solution (×10⁵) was 17.77%, and the incidence and disease index decreased. After 30 days of pathogen inoculation, malondialdehyde (MDA) contents of the seedlings treated by different concentrations of suspensions all decreased, but lignin, solution protein and solution sugar contents increased. MDA content had significant positive correlation with incidence and disease index, but had significant negative correlation with the control, while lignin, solution protein and solution sugar contents increased. In field tests, the cure ratios of disease spots treated with original solution and diluent solution (×10, ×10², ×10³) were over 80%. These results indicated that B.amyloliquefaciens Ba4 had excellent control effect on pine dieback and could promote the composition of resistant substance of P.armandii.