【作者】 马慧宁；

【导师】 张莉；

【作者基本信息】 石河子大学 ， 植物病理学， 2007， 硕士

【摘要】 本研究旨在分离、筛选能够抑制棉花黄萎病菌的拮抗微生物,并对筛选出的菌株进行鉴定和拮抗机理的研究;此外,对黑白轮枝菌和大丽轮枝菌ITS区段进行了分析。主要研究结果如下:1、用稀释平板法,从棉花根部土壤中分离得到1723个菌株。通过平板筛选,得到113个对黄萎病菌有拮抗作用的菌株。对其中拮抗效果明显的37个菌株进行了平板拮抗效果测定、温室盆栽防治黄萎病效果的测定及广谱抗性的鉴定。结果显示,平板拮抗效果明显的37个菌株在盆栽实验中仍对黄萎病表现抗性的有24株;同时,这37个拮抗菌株都不同程度地表现出广谱抗性。2、对筛选出的三个拮抗效果明显的细菌菌株进行了鉴定。利用形态学鉴定和生理生化特性鉴定相结合的方法将菌株112初步鉴定为芽孢杆菌属的巨大芽孢杆菌,将菌株868初步鉴定为假单胞菌属的荧光假单胞菌;利用形态学鉴定、生理生化特性鉴定及细菌16SrDNA序列分析相结合的方法,将菌株312鉴定为芽孢杆菌属的腊状芽孢杆菌。3、对筛选出的三个拮抗效果明显的菌株进行了拮抗机理的研究。结果表明,菌株112和868都不产生嗜铁素和几丁质酶,但有具抗生作用的次生代谢物产生。诱导系统抗性实验结果显示,用三个拮抗菌株接种棉花后,棉花植株内的三种防御酶POD、PPO和PAL都有不同程度的提高,说明供试的拮抗菌株能够诱导棉花植株产生系统抗病性。更多还原

【Abstract】 The purpose of this study is to separate and screen the antagonistic microorganism that can restrain verticillium wilt of cotton, to identify strain screened and to study the mechanism of antagonism, and to analysis the ITS region of Verticillium albo-atrum and V.dahliae’s . The main results are as follows.1. 1723 strains were separated from the soil around the cotton root by the diluted plate method. 113 strains that are antagonistic to Verticillium dahliae were screened on the plate. The antagonistic effect on the plate,the effect of potted plant in greenhouse to control the cotton wilt disease and the broad-spectrum resistance were examined in 37 stains which are obviously antagonistic. The results show that 24 strains of 37 strains which are obviously antagonistic on the plate are resistant to cotton wilt disease in potted plant experiment.37 antagonistic strains have different broad-spectrum resistance.2. 3 bacterial strains which have obviously antagonistic effect were identified. The strain 112 was identified to be Bacillus megaterium according to morphology and physiological and biochemical trait. The strains 868 was identified to be Pseudomonas Fluorescens. The strain 312 was identified to be Bacillus cereus according to morphology, physiological and biochemical trait and 16SrDNA sequence analysis.3. The antagonistic microorganism of 3 bacterial strains which have obviously antagonistic effect was studied. The results show that the strain 112 and the strain 868 can not produce Siderophore and chitinase, but can produce secondary metabolite which have antibiosis. The result of the derivational systemic resistance experiment shows that the activity of the three defensive enzyme (i.e. POD, PPO and PAL) in cotton inoculated with three antagonistic strains enhanced, indicating that the antagonistic strains tested can induce systemic resistance in cotton.更多还原