番茄灰霉病拮抗内生细菌的筛选、鉴定及其活性

Screening,identification,and bioactivity of an endophytic bacterium from tomato against Botrytis cinerea.

对安徽省淮北市番茄植株根、茎、叶中内生细菌及其数量进行了调查和筛选,并测定了其抑菌活性。结果表明,番茄根、茎和叶中的内生细菌的数量分别为5.69×105、5.16×105和2.83×105CFU.g-1鲜重。根据分离部位和表型特征,从健康番茄植株体内分离到267株内生细菌,通过对峙实验,筛选到11株对番茄灰霉病菌有拮抗作用的菌株,占所分离内生细菌总数的4.12%。来自茎组织中的菌株XF136的抑菌效果最佳,抑菌带宽度达32.2mm。根据形态特征、生理生化特性、(G+C)mol%和16SrDNA序列分析,将菌株XF136鉴定为解淀粉芽孢杆菌(Bacillus amyloliquefaciens)。室内测定菌株XF136发酵滤液对灰霉病菌菌丝生长及分生孢子萌发的抑制作用,结果表明,菌株XF136发酵滤液可以抑制灰霉病菌菌丝生长和分生孢子萌发,且浓度越高,抑制能力越强;当发酵滤液浓度为20%时则完全抑制灰霉病菌菌丝生长和分生孢子萌发。盆栽防效试验结果表明,10%菌株XF136发酵滤液对番茄灰霉病防治效果与50%多菌灵600倍液相当,20%发酵滤液对番茄灰霉病的防治效果高于50%多菌灵600倍液。本研究表明,菌株XF136是防治番茄灰霉病潜在的优良生防菌株,具有良好的开发应用价值。

An investigation was conducted on the endophytic bacteria in the roots,stems,and leaves of tomato plants collected from the farmlands in Huaibei City of Anhui Province,East China,and the bacterial strains were screened,with their bioactivities against pathogenic fungus Botrytis cinerea determined.The population density of the endophytic bacteria in the roots,stems and leaves of tomato plants was 5.69×105,5.16×105 and 2.83×105 CFU·g-1 fresh weight,respectively.According to the isolation position and phenotype,267 endophytic bacteria strains were isolated from different internal tissues of tomato plants.By using a dual culture technique,11 strains,accounting for about 4.12% of the endophytic bacteria and exhibiting antagonistic activities against B.cinerea,were screened,among which,strain XF136 isolated from tomato stem had the best inhibitory effect,and formed an inhibition zone with a width of 32.2 mm.The XF136 strain was identified as Bacillus amyloliquefaciens,based on its morphological,physiological,and biochemical properties,（G＋C） mol%,and 16S rDNA sequence analysis.The laboratory test with the XF136 culture filtrate showed that the filtrate was effective in inhibiting the mycelium growth and spore germination of B.cinerea,and,the higher the filtrate concentration,the stronger the inhibition effect,with the mycelium growth and spore germination of B.cinerea completely inhibited at the filtrate concentration 20%.The pot experiment demonstrated that the prevention efficiency and cure efficiency of 10% culture filtrate of XF136 against tomato gray mould were equivalent to those of 50% Badistan 600-fold dilution,and the control efficiency of 20% culture filtrate of XF136 was superior to that of 50% Badistan 600-fold dilution.This study indicated that the strain XF136 was potentially valuable in the biological control of tomato gray mould,and had favorable development and practical prospects.