恶臭假单胞菌HB3S-20在棉花中的定殖及诱导抗性研究

The Colonization and Induced Resistance of Pseudomonas putida HB3S-20 in Cotton

植物内生菌是防治植物病害的重要生防资源。恶臭假单胞菌Pseudomonas putida HB3S-20是本实验室从棉花内生细菌中所筛选到的一株对棉花黄萎病具有显著防效的潜在生防菌株。本研究采用利福平抗性标记技术和绿色荧光蛋白(GFP)标记技术检测了菌株HB3S-20在棉花组织中的定殖动态和定殖位点,并检测了菌株HB3S-20接种棉花植株后植物防御相关酶SOD、POD和CAT酶活性的变化。利福平标记试验结果表明,菌株HB3S-20主要定殖于根部,棉株接种菌株HB3S-20后第3~30 d检测到棉花根部内的菌量范围为2.2×10^(4)~6.7×10^(4)cfu/g,检测到棉花茎部内的菌量为0.04×104~2.7×10^(4)cfu/g,棉花茎部内的菌量低于根部,但在叶片中未被分离到。GFP标记试验结果表明,菌株HB3S-20不仅能附着在棉花根系表面,还能定殖在根部维管组织中。此外,菌株HB3S-20能够提高棉花中植物防御相关酶SOD和POD的活性,说明菌株HB3S-20能够诱导棉花植株的系统抗性,增强棉花抗病性。本研究初步揭示了恶臭假单胞菌HB3S-20在棉花组织内的定殖规律及其对棉株产生的诱导抗性,为菌株HB3S-20的防病机制研究提供了理论依据。

Endophytes are important biocontrol resources in controlling plant diseases.The Pseudomonas putida HB3S-20 was screened as a potential biocontrol agent which had significant control effect against cotton Verticillum wilt in our laboratory.The colonization dynamics and colonization sites of strain HB3S-20 in cotton tissues were detected using rifampicin resistance labeling technique and GFP labeling technique in this study.Moreover,the activities of the plant defense-related enzymes SOD,POD and CAT of cotton after inoculation of the strain HB3S-20 were detected.The rifampicin resistance labeling experiment showed that the strain HB3S-20 mainly colonized the roots of cotton,the amount of bacteria of the strain HB3S-20 detected in cotton roots ranged from 2.2×10^(4) to 6.7×10^(4) cfu/g on the 3rd to 30th day after inoculation of the strain HB3S-20.The amount of bacteria of the strain HB3S-20 detected in cotton stems ranged from 0.04×10^(4) to 2.7×10^(4) cfu/g,lower than the amount of bacteria in roots,but not found in leaves.The results of GFP labeling experiment showed that the strain HB3S-20 not only attached to the surface of cotton roots but also colonized the vascular system of cotton roots.Moreover,the strain HB3S-20 could increase the activities of the plant defense-related enzymes SOD and POD in cotton,and it indicated that the strain HB3S-20 could induce systemic resistance and enhance the resistance of cotton to the pathogens.In this research,the colonization regulation and induced resistance of Pseudomonas putida HB3S-20 in cotton were studied,which provides theoretical basis for the mechanism of the strain HB3S-20 controlling cotton Verticillium wilt.