广西烟草内生细菌的动态分布及其对烟草疫霉的拮抗作用

Dynamic distribution of endophytic bacteria and their antagonism to phytophthora nicotianae in tobacco plant in Guangxi

从广西百色市的9个烟草品种中分离出470株内生细菌菌株,经常规细菌鉴定方法和16S rDNA序列分析,获得的菌株分别属于肠杆菌属(Enterobacter)、沙雷氏菌属(Serratia)、芽孢杆菌属(Bacillus)、土壤杆菌属(Agrobacterium)、寡养单胞菌属(Stenotro-phomnas)和假单胞菌属(Pseudomonas),其中土壤杆菌属和肠杆菌属为烟草内生细菌中的优势种群。烟草内生细菌的类群和数量随烟草种植地点、品种、器官和生育期的不同而不同。烟草内生细菌在根部数量最多,其次是茎和叶。内生细菌的总量从缓苗期到旺长期增加,之后显著下降。从470株烟草内生细菌菌株中筛选出对烟草疫霉有拮抗作用的菌株56株,其中芽孢杆菌菌株Y10的抑制效果最好,抑制率达91.48%,室内盆栽防治效果为68.72%。

470 bacterial strains were isolated from 9 tobacco cultivars collected from Guangxi province. Based on conventional methods and 16s DNA sequence analysis, these strains were identified as Enterobacter, Serratia, Bacillus, Agrobacterium, Stenotrophomna and Pseudomonas, of which Agrobacterium and Ertterobacter were dominant genus. The genera and population of endophytic bacteria in tobacco plants varied with cultivating regions, cultivars, tissues and growth stages. The endophytic bacteria were most frequently isolated in roots, followed by stems and leaves. Total amount of endophytic bacteria increased gradually from seedling stage to flourishing stage, and then decreased dramatically. 56 of the 470 isolates exhibited antagonistic activity against Phytophthora nicotianae, and Bacillus subtilis strain Y10 was the strongest antagonist with an inhibitory rate of 91.48%. The control efficacy of strain Y10 on tobacco black shank was 68.72% in greenhouse.