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为明确植物内生细菌在棉花体内的定殖规律及对棉花黄萎病防治效果的影响,采用对峙培养法筛选对大丽轮枝菌Verticillium dahliae Kleb.抑菌活性强的植物内生细菌,通过形态及生理生化特征并结合16S r DNA和gyr B基因分析鉴定菌株;利用抗生素标记法及盆栽试验研究其在棉花体内的定殖动态及对棉花黄萎病的防治效果。结果表明:共筛选到3株对大丽轮枝菌具有强抑菌活性的菌株SZ5、DP10和CCM9,其中SZ5为蜡样芽胞杆菌Bacillus cereus,定殖在棉花根部、茎部和叶部,DP10和CCM9为枯草芽胞杆菌B.subtilis,定殖在棉花根部和茎部,3株菌在棉花根部的定殖数量均在10~3CFU/g以上;棉花苗沾根分别接入3株内生细菌10 d后再接种大丽轮枝菌孢子悬浮液,对棉花黄萎病的防治效果达79.52%~89.79%,而3株内生细菌沾根接种后立即移栽到含有大丽轮枝菌的土壤中对棉花黄萎病的防治效果为23.77%~36.03%。表明不同内生细菌菌株在棉花体内的定殖规律不同;且在棉苗中定殖一定数量后,才能对棉花黄萎病产生较高的防治效果。
In order to clarify the colonization rules of plant endophytic bacteria in cotton and the control effect on cotton Verticillium wilt, the endophytic bacteria with strong antibacterial activity against Verticillium dahliae Kleb were selected by confrontation culture method, Morphological, physiological and biochemical characteristics of the isolates, and the combination of 16S r DNA and gyr B gene analysis to identify strains; using antibiotic markers and pot experiments to study its colonization dynamics in cotton and its control effect on cotton Verticillium wilt. The results showed that three strains of SZ5, DP10 and CCM9 with strong antibacterial activities against Verticillium dahliae were screened, of which SZ5 was Bacillus cereus and colonized the roots, stems and leaves of cotton. DP10 And CCM9 were Bacillus subtilis B. subtilis colonized in the roots and stems of cotton. The colonization numbers of the three strains in the roots were above 10 ~ 3CFU / g. Three strains of endophytic bacteria 10 d after inoculation of Verticillium dahliae spore suspension, the control effect of cotton Verticillium wilt reached 79.52% ~ 89.79%, and 3 endophytic bacteria stained roots immediately after inoculation transplanted to contain Verticillium dahliae The control effect of Verticillium wilt in soil was 23.77% ~ 36.03%. The results showed that the colonization of different endophytic bacteria strains in cotton is different; and colonization of a certain number of cotton seedlings in order to have a high control effect on cotton Verticillium wilt.