和田鞘氨醇杆菌AMCC 100218菌株的筛选、鉴定及杀线虫特性

为筛选对南方根结线虫具有致死效果的生防细菌，从山东省10个县市蔬菜主产区番茄根际土壤中分离可培养细菌，采用离体杀线虫试验测定分离菌株对南方根结线虫Meloidogyne incognita的致死活性，结合生理生化特征及分子生物学方法对高效杀线虫菌株进行分类鉴定，同时对其杀线虫特性进行表征，并通过盆栽试验进一步验证其生防潜力。结果显示，从山东省蔬菜主产区番茄根际土中分离到1株高效杀线虫菌株AMCC 100218，结合生理生化试验与16S rRNA序列分析，鉴定此菌株为和田鞘氨醇杆菌Sphingobacterium hotanense；该菌株对南方根结线虫2龄幼虫的致死效果可达88.87%，其杀线虫活性物质具有较好的热稳定性和储存稳定性，且耐碱不耐酸；盆栽试验结果表明，该菌能够显著减少土壤中的虫口密度，降低番茄发病率。表明和田鞘氨醇杆菌AMCC 100218菌株是1株具有防治根结线虫病潜力的生防细菌。

Isolation and identification of Sphingobacterium hotanense AMCC 100218, and characterization of its nematicidal properties

In order to screen and obtain culturable bacteria with high a nematicidal activity against root-knot nematode Meloidogyne incognita, bacterial strains were isolated from tomato rhizosphere soils collected from ten locations in Shandong Province. The nematicidal activities of these strains were determined by in vitro nematicidal tests. Based on the physiological and biochemical characteristics, as well as 16S rRNA sequence, the bacterial strain with good nematicidal activity was then identified, and its nematicidal properties were characterized, meanwhile its biocontrol potential was further verified in pot experiment. A bacterial strain AMCC 100218 identified as Sphingobacterium hotanense showed a high nematicidal activity (88.87%) against J2s of M. incognita. The substance responsible for nematicidal activity showed thermal and storage stability, was alkali resistant, but could be easily damaged by acid substances. Pot experiments demonstrated that S. hotanense AMCC 100218 could significantly reduce the density of J2s of M. incognita in the soil and reduce the incidence of tomato root knot caused by the nematodes. The results indicated that the strain S. hotanense AMCC 100218 had a potential as a biocontrol agent for controlling root knot nematodes.