番茄土传病害拮抗菌的筛选和鉴定

摘要

Objective] This study was conducted to screen resources for biological control of soil-borne diseases of tomato. [Method] Antagonistic bacteria against Ral-stonia solanacearum and Fusarium oxysporum were isolated and purified from soil samples by dilution plating and confronting incubation on PDA plates, then the an-tibacterial spectrum and metabolic secretions of the bacterial isolates were mea-sured, and their species were identified by establishing phylogenetic trees with Neighbor-Joining method. [Result] From the 60 soil samples, 10 of 59 antagonistic bacteria isolates against R. solanacearum showed inhibition zone diameter > 25 mm, and 4 of 30 strains against F. oxysporum exhibited inhibition rate > 30%. The bacteriostatic substances and antibacterial spectrum analysis on above 14 isolates revealed that four strains N23-2, N58-2, NF59-3 and NF61-1 had good antago-nism against pathogenic bacteria and fungi; 12 strains produced cel ulose, 11 strains produced proteases, and 6 strains produced siderophores. The molecular identifica-tion experiments indicated that four strains were members of Paenibacil us, three strains of Streptomyces, three strains of Pseudomonas strains, and four strains of Bacil us strains.%[目的]筛选出对番茄土传病有防治效果的生防菌。[方法]该研究以番茄青枯病菌（Ralstonia solanacearum）和番茄枯萎病菌（Fusarium oxysporum）为靶标菌，利用梯度稀释涂板法和平板对峙生长法从土样中分离、筛选出分别对这2种病原菌具有较强抑制作用的拮抗细菌；并对其抑菌谱及代谢分泌物进行测定，运用 Neighbor-Joining方法构建系统发育树，对拮抗细菌进行种属鉴定。[结果]从60份土样中分离出对番茄青枯病菌有拮抗作用的细菌59株，其中抑菌圈直径＞25 mm的有10株；对番茄枯萎病菌有拮抗作用的细菌30株，其中抑制率＞30％的有4株。上述14株菌株中, N23-2、N58-2、NF59-3、NF61-1对多种病原细菌和病原真菌皆具有较好的拮抗作用；产纤维素酶的菌株有12株，产蛋白酶的菌株有11株，产嗜铁素的菌株有6株。种属鉴定结果表明 ： 有4 株属多粘芽孢杆菌（Paenibacillus），3株属链霉菌（Streptomyces），3株属假单胞菌（Pseudomonas），4株属芽孢杆菌（Bacillus）。[结论]该研究结果为番茄土传病害的生物防治提供更多的微生物资源。