---

期 刊 ：植物保护学报 2010年

关键词：内生细菌；烟草黑胫病菌；枯草芽孢杆菌；病害生物防治；

Keywords:endophytic bacteria, Phytophthora nicotianae, Bacillus subtilis, disease biological control,

摘 要 ：Itb57是一株分离自健康烟草植株的内生细菌,室内测定表明,该菌株对烟草黑胫病菌Phytophthora nicotianae具有很强的拮抗作用。为了进一步明确其分类地位和生物防治潜力,结合形态、生理生化特性及16S rDNA 序列(GenBank登录号GQ153538)比对分析,鉴定Itb57菌株为枯草芽孢杆菌Bacillus subtilis;浸种和灌根接种测定结果显示,Itb57可定殖在烟草植株体内,且在不同部位的含菌量不同,以根部最高(3.72×10⁴cfu/g FW),茎部次之,叶片中最少;Itb57发酵液对烟草黑胫病的温室防治效果为69.28%;2007和2008年的田间小区防治效果分别为61.25%和72.49%,与对照化学药剂58%甲霜·锰锌可湿性粉剂的防治效果无显著差异(P>0.05)。

Abstract:The endophytic bacterial isolate Itb57 was obtained from healthy tobacco plants and it was showed antagonistic effect against Phytophthora nicotianae causing tobacco black shank by in vitro tests. In order to determine its taxa and potential application in biological control, Itb57 was identified and its efficacy to control tobacco black shank was evaluated in this study. Based on morphological, physiological and biochemical characteristics, and 16S rDNA (GenBank accession GQ153538) phylogenetic analysis, Itb57 was identified as Bacillus subtilis. After tobacco plants were inoculated by seed-soaking and root-irrigation with the bacterial suspension, Itb57 was found to colonize the interior tissues of tobacco plants. The highest amount (3.72×10⁴cfu/g fresh weight) of the inoculated bacterium was detected in the roots while the lowest in the leaves of the plants. Greenhouse pot-grown tobacco plant assays showed that the control efficacy of black shank by Itb57 was 69.28% when the bacterium was applied by root-irrigation in advance of P.nicotianae inoculation. Further, field trials in 2007 and 2008 in Youyang County of Chongqing demonstrated that the application of Itb57 controlled the disease by 61.25% and 72.49%, respectively. Statistical analysis indicated that the disease control efficacy was not significantly different from that obtained by treatment with 58% metalaxyl mancozeb (P>0.05).

---