石榴干腐病生防菌株Z2的鉴定及其培养条件的优化

 从石榴根际土壤中分离获得一株生防细菌菌株Z2。根据16S rDNA、gyrA 基因序列分析和特定基因的选择性扩增,结合形态学、生理与生化特性鉴定和Biolog 检测,将生防菌株Z2鉴定为解淀粉芽胞杆菌(Bacillus amyloliquefaciens)。通过单因素试验研究菌株的培养条件,并经过正交实验设计对培养条件进行优化,探究生防菌对Zythia versoniana引起的石榴干腐病的防治效果。生防菌株Z2的优化培养条件为:温度27℃,pH =6或8,LB培养基,培养时间3 d。采用新鲜离体石榴果实针刺接种方法进行菌株生防效力检测,与其他供试植物病原真菌相比,菌株Z2对石榴果实干腐病菌Z. versoniana具有较强的抑菌活性,对石榴果实干腐病的病斑抑制率达31.27%~81.89%。本研究获得的生防菌株Z2对石榴干腐病生物防治具有开发应用潜力,优化的培养条件可为该生防菌的产业化和大田应用奠定基础。另外,菌株Z2对植物病原真菌有较宽的抑菌谱,表明该菌株对其他作物病害的防治也具有潜在的应用价值。

Identification of a biocontrol strain Z2 against pomegranate dry rot and optimization of its cultural conditions

A biocontrol strain Z2 was isolated from the rhizosphere soil of pomegranate (Punica granatum), and identified as Bacillus amyloliquefaciens based on phylogenetic analyses of 16S rDNA and gyrA gene sequences and selective amplifications of specific genes as well as morphological, physiological, biochemical characterizations and Biolog detection. The cultural conditions of the strain were investigated by single factor experiment, and optimized using orthogonal experimental design to enhance its biocontrol efficacy against Zythia versoniana causing pomegranate dry rot (PDR). The optimized cultural conditions of strain Z2 were obtained as a combination of temperature 27 °C, pH =6 or 8, LB medium and incubation time 3 d. The biocontrol efficacy of the strain was tested by needle inoculation on freshly detached pomegranate fruit under the optimized cultural conditions. The strain Z2 had stronger suppressive activity against Z. versoniana compared with other fungal phytopathogens tested. The lesion inhibition rates of pomegranate fruit dry rot reached to 31.27%-81.89% by strain Z2. The strain Z2 could be thus considered a promising biocontrol agent against PDR. The optimized cultural conditions lay a foundation for industrialization and field application of the biocontrol agent. In addition, a broad suppressive spectrum of strain Z2 against fungal phytopathogens was observed, indicating the potential of strain Z2 as biocontrol agent against other plant diseases as well as PDR.