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两株芽胞杆菌的分离鉴定及其对根结线虫病的防治效果

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南方根结线虫(Meloidogyne incognita)引起的作物根结线虫病分布广泛,危害严重.为了筛选根结线虫病的生防资源,本研究从扬州蔬菜田土壤中分离了两个具有较高杀线虫活性的细菌菌株HJ03和HJ04.综合形态学特征、生理生化特性和分子进化分析结果,将这两株菌分别鉴定为解淀粉芽胞杆菌(Bacillus amyloliquefaciens)和沙福芽胞杆菌(Bacillus safensis).HJ03和HJ04培养液处理M.incognita二龄幼虫24 h的校正死亡率分别为77.3%和79.3%,其无细胞培养滤液处理的校正死亡率分别为75.9%和80.1%,两种处理之间差异不显著;培养24 h即可获得较好的杀线虫效果,更长的培养时间不能显著增加致死率;以OD600=1.2的1倍菌液为原液,稀释2倍后致死率分别为77.7%和78.6%,和原液相比下降不显著,稀释5倍致死率显著下降.抑制线虫机制的研究结果表明:HJ03和HJ04能抑制卵孵化,相比LB处理的对照相对抑制率分别达到71.1%和64.0%;可显著减少番茄根尖1 cm周围二龄幼虫数量,抑制率分别达到90.9%和87.6%;能显著抑制二龄幼虫侵染,接虫1周后抑制率分别达到85.4%和85.2%;可显著抑制根结形成,接虫40 d后根结指数分别为1.1和1.6,相比LB培养基处理的对照(3.3)明显下降;可抑制卵囊形成,接虫60 d后的抑制率分别为75.7%和73.1%;可显著减少线虫诱导寄主产生的巨细胞的大小.此外,HJ03和HJ04还能促进番茄种子萌发和植株生长.本研究丰富了作物根结线虫病的生防资源,为进一步开发线虫生防菌剂奠定了基础.
Identification and biocontrol effect of two Bacillus strains against root-knot disease
Root-knot disease,caused by Meloidogyne incognita,seriously threatens the production of many crop plants.To further explore biocontrol resources for this disease,two bacterial strains showing nematicidal ac-tivity were isolated from vegetable rhizopsheric soil in Yangzhou City,China.These two strains,named HJ03 and HJ04,were identified as Bacillus amyloliquefaciens and B.safensis,respectively,based on their morphologi-cal characteristics,biochemical properties,and phylogenetic analysis results.The corrected mortalities of HJ03 and HJ04 cell suspensions against second-stage juveniles(J2s)of M.incognita after 24 h of treatment were 77.3%and 79.3%,respectively,while those for culture filtrates of the two strains were 75.9%and 80.1%.No significant difference in corrected mortalities was observed between treatments with cell suspension and culture filtrate.Cell suspensions of HJ03 and HJ04 cultured for 24 h showed good nematicidal activity,and extended culture time did not significantly increase nematicidal activity.Cell suspensions(OD600=1.2)of HJ03 and HJ04 diluted to 1:2 resulted in mortalities of 77.7%and 78.6%,respectively,similar to those caused by their mother solutions,but showed significantly decreased mortalities when diluted to 1:5.The biocontrol mechanisms of HJ03 and HJ04 against M.incognita were revealed as follows:HJ03 and HJ04 can inhibit egg hatching of M.in-cognita,with inhibition rates of 71.1%and 64.0%,respectively,compared to LB medium-treated control;sig-nificantly inhibit the chemotaxis of J2s.The number of J2s in tomato rhizosphere(1 cm)treated with HJ03 and HJ04 was reduced by 90.9%and 87.6%,respectively,compared with that of control;dramatically inhibit nema-tode infection,with inhibition rates of 85.4%and 85.2%,respectively,after treated with HJ03 and HJ04 for one week;inhibit gall formation,with gall indexes of 1.1 and 1.6 for HJ03 and HJ04,respectively,at 40 d after treatment,whereas 3.3 for control;inhibit the formation of egg masses,with inhibition rates of 75.7%and 73.1%for HJ03 and HJ04,respectively,at 60 d after treatment;reduce the size of M.incognita-induced giant cells.In addition,HJ03 and HJ04 can promote seed germination and seedling growth of tomato.This study enri-ches the biocontrol resources against root-knot disease and lays a basis for further development of biocontrol agents.

Meloidogyne incognitaBacillusbiological controlplant growth-promoting

刘雅洁、罗书介、蒋晓惠、张清霞、魏霜

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扬州大学植物保护学院,扬州 225009

植物功能基因组学教育部重点实验室,扬州大学农学院,扬州 225009

广州海关技术中心,广州 510632

南方根结线虫 芽胞杆菌 生物防治 促生

国家重点研发计划

2022YFC2601500

2024

植物病理学报
中国植物病理学会

植物病理学报

CSTPCD北大核心
影响因子:0.865
ISSN:0412-0914
年,卷(期):2024.54(3)