| 摘要: |
| 【目的】探究内生嗜线虫镰刀菌（Fusarium nematophilum）NQ8GⅡ4诱导番茄抗枯萎病的作用机制，为番茄枯萎病的生物防治提供理论依据。【方法】以从健康枸杞根部分离的内生嗜线虫镰刀菌（F.nematophilum）NQ8GⅡ4菌株和番茄枯萎病原菌尖孢镰刀菌（F.oxysporum f.sp.lycopersic）Fol-1菌株为材料，采用皿内对峙法测定NQ8GⅡ4菌株对番茄枯萎病菌Fol-1的体外拮抗活性，通过温室盆栽试验测定NQ8GⅡ4菌株对番茄枯萎病的防治效果。采用组织化学染色探究NQ8GⅡ4菌株对番茄植株活性氧、膜脂过氧化及细胞死亡的影响，采用紫外可见分光光度计测定NQ8GⅡ4菌株对番茄植株防御酶活性及丙二醛含量的影响，采用RT-qPCR扩增明确NQ8GⅡ4菌株对番茄植株防御相关基因表达量的影响，探究NQ8GⅡ4菌株诱导番茄抗枯萎病的生理生化机理。【结果】平板对峙试验结果显示，NQ8GⅡ4对Fol-1菌株生长有明显抑制作用，不论是同时接种NQ8GⅡ4和Fol-1处理还是先接种NQ8GⅡ4培养3 d后再接种Fol 1菌株处理，NQ8GⅡ4菌落与Fol-1菌落之间均出现了明显的抑菌带，且抑菌带边缘的Fol-1生长受到明显抑制。与同时接种NQ8GⅡ4和Fol-1菌株相比，先接种NQ8GⅡ4菌株培养3 d后再接种Fol-1菌株，NQ8GⅡ4对Fol-1的抑制作用更强，抑制率为60.00%。激光扫描共聚焦荧光显微镜观察发现，接种50 d后GFP-NQ8GⅡ4菌株能成功定植于番茄根部，定植率高达91.84%。盆栽试验发现，NQ8GⅡ4能显著降低番茄枯萎病的发生，防效高达76.85%。组织化学染色结果显示，与对照（CK）相比，单接种NQ8GⅡ4对番茄叶片的H2O2、O-·2和膜脂过氧化无显著影响；单接种Fol-1菌株处理组番茄叶片活性氧显著爆发，膜脂过氧化和细胞死亡程度严重。与单接种Fol-1处理组相比，接种NQ8GⅡ4和Fol-1菌株处理组番茄叶片的活性氧爆发程度显著降低，略有膜脂过氧化但发生程度显著降低，且未检测到明显的细胞死亡。进一步研究发现，与对照（CK）相比，单独接种NQ8GⅡ4处理接种前期CAT、POD活性增加，后期SOD、β-1,3-GA和PAL等防御酶活性显著增强。与单独接种病原菌Fol-1处理相比，NQ8GⅡ4和Fol-1共同处理的番茄植株防御酶活性增加，丙二醛含量降低。RT-qPCR检测结果表明，接种NQ8GⅡ4 120 h后，能显著诱导番茄PR1a、GLUA、NPR1、WRKY33和Basic CHI 5个防御相关基因的上调表达。【结论】内生嗜线虫镰刀菌NQ8GⅡ4不仅能显著抑制番茄枯萎病原菌尖孢镰刀菌的生长，促使番茄防御相关酶活性的提高，而且还可以通过激活番茄的SA和JA防御信号途径，诱导番茄植株对枯萎病的抗性，显著降低了番茄枯萎病的发生，在番茄枯萎病生物防治中具有潜在的应用前景。 |
| 关键词: 内生嗜线虫镰刀菌 番茄枯萎病 生物防治 诱导抗病机制 |
| DOI：10.13207/j.cnki.jnwafu.2025.10.013 |
| 分类号: |
| 基金项目:国家自然科学基金项目（32260697） |
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| Mechanism of the endophytic Fusarium nematophilum NQ8GⅡ4 in inducing wilt resistance in tomato |
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GUO Miaomiao1, LI Jin2, JIA Shuxin1, YAN Siyuan1, GU Peiwen1
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1.School of Agriculture,Ningxia University,Yinchuan,Ningxia 750021,China;2.Liupanshui Agricultural Science Research Institute,Liupanshui,Guizhou 553000
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| Abstract: |
| 【Objective】This study aimed to investigate the action mechanism of endophytic Fusarium nematophilum NQ8GⅡ4 in inducing wilt resistance in tomato,to provide a theoretical basis for the biological control of tomato wilt.【Method】F.nematophilum strain NQ8GⅡ4 and tomato wilt pathogen F.oxysporum f.sp.lycopersic Fol-1 were isolated from healthy roots of Lycium barbarum as the materials.In-dish standoff method was used to determine the in vitro antagonistic activity of NQ8GⅡ4 strain against tomato wilt Fol-1,and greenhouse pot test was used to determine the efficacy of strain NQ8GⅡ4 in the control of tomato wilt.Histochemical staining was used to investigate effects of NQ8GⅡ4 strain on reactive oxygen species,membrane lipid peroxidation and cell death in tomato plants.UV-visible spectrophotometer was used to determine the effect of strain NQ8GⅡ4 on defense enzyme activities and malondialdehyde content of tomato plants.The RT-qPCR amplification was used to clarify the effect of NQ8GⅡ4 strain on the expression of defense-related genes in tomato plants,and to investigate the physiological and biochemical mechanisms of NQ8GⅡ4 strain in inducing blight resistance in tomato.【Result】The plate standoff test showed that NQ8GⅡ4 had a significant inhibitory effect on the growth of Fol-1 strain.In both the treatment of inoculation of NQ8GⅡ4 and Fol-1 at the same time and the treatment of inoculation of NQ8GⅡ4 and cultivation for 3 d before the inoculation of the Fol-1 strain,a clear inhibitory band was observed between the NQ8GⅡ4 colonies and Fol-1 colonies,and the growth of Fol-1 at the edge of the inhibition zone was significantly inhibited.Compared with simultaneous inoculation of NQ8GⅡ4 and Fol-1 strains,inoculation of NQ8GⅡ4 strain and cultivation for 3 d before inoculation of Fol-1 strain resulted in stronger inhibition effect on Fol-1 by NQ8GⅡ4,with an inhibition rate of 60.00%.Laser scanning confocal fluorescence microscopy revealed that the GFP-NQ8GⅡ4 strain was able to successfully colonize in tomato roots 50 d after inoculation,with a high colonization rate of 91.84%.The pot test found that NQ8GⅡ4 could significantly reduce the incidence of tomato wilt,with high preventive effect of 76.85%.Histochemical staining showed that single inoculation of NQ8GⅡ4 had no significant effect on H2O2,O-·2 and membrane lipid peroxidation in tomato leaves compared to the control.A significant burst of reactive oxygen species,severe degree of membrane lipid peroxidation and cell death was observed in tomato leaves of single Fol-1 strain inoculation treatment.Tomato leaves of the NQ8GⅡ4 and Fol-1 strain inoculation treatment showed significantly lower reactive oxygen burst,slight membrane lipid peroxidation at a significantly lower level of occurrence,and no significant cell death was detected as compared to the single Fol-1 strain inoculation treatment group.It was further found that CAT and POD activities were increased in the pre-inoculation period and defense enzymes of SOD,β-1,3-GA and PAL activities were significantly enhanced in the later period of single NQ8GⅡ4 inoculation treatment as compared to the control.Tomato plants of the NQ8GⅡ4 and Fol-1 strain inoculation treatment showed increased defense enzyme activity and decreased malondialdehyde content compared to the single Fol-1 inoculation treatment.The results of RT-qPCR assay showed that inoculation with NQ8GⅡ4 for 120 h significantly induced the up-regulated expression of 5 defense-related genes,namely,PR1a,GLUA,NPR1,WRKY33 and Basic CHI in tomato.【Conclusion】Endophytic F.nematophilum NQ8GⅡ4 not only significantly inhibited the growth of the tomato wilt pathogen F.oxysporum f.sp.lycopersic,which could lead to the increase of the activity of tomato defense-related enzymes,but also induced the resistance of tomato plants to wilt by activating the SA and JA defense signaling pathways in tomato,significantly reducing the occurrence of tomato wilt.It has potential application prospect in the biocontrol of tomato wilt. |
| Key words: endophyte F.nematophilum tomato wilt disease biological control defense mechanism |
