丛枝菌根真菌对不同番茄品种抗根结线虫病的影响

Effect of inoculation with arbuscular mycorrhizal fungi on root-knot nematode (Meloidogyne incognita) in tomato cultivars

摘要:

【背景】根结线虫病害严重制约我国设施蔬菜的生产。丛枝菌根真菌(Arbuscular Mycorrhizal Fungi，AMF)作为土壤中最重要的有益真菌之一，可以促进植物生长，提高植物抗病性，减轻土传真菌和线虫病害的发生。在蔬菜保护地栽培中，AMF对于植物线虫病防治作用的研究受到了广泛关注。【目的】针对番茄生产中危害最严重的南方根结线虫(Meliodogyne incognita)病害问题，研究AMF和番茄品种不同组合的抗线虫效应，以期为菌根真菌作为生物防治剂和生物菌肥应用于实际生产提供技术基础。【方法】在灭菌土壤中，人工接种根结线虫，比较不同菌种Rhizophagus intraradices (Ri)、Acaulospora mellea (Am)及菌种组合Rhizophagus intraradices+Acaulospora mellea (Ri+Am)在不同番茄品种(感病品种蒙特卡罗和抗线虫品种仙客1号)上对南方根结线虫侵染和繁殖的影响，研究AMF对根结线虫的拮抗效应。另外，采用南方根结线虫连作发病的土壤，在感病品种蒙特卡洛上接种AMF混合菌种Ri+Am，番茄苗移栽入连作土壤中，测定各生长指标和调查根结和卵块数量，评价接种AMF处理对根结线虫病的防治效果。【结果】在灭菌土壤中，普通番茄品种蒙特卡罗的菌根效应显著优于抗线虫番茄品种仙客1号，表现为前者单位根重的根结和卵块的数量均比对照显著降低，而后者仅降低了卵块数量；蒙特卡罗上接种Ri+Am混合菌种的效果优于接种单一菌种Am和Ri；而仙客1号上接种Ri的效果更好。接种线虫也显著影响了AMF的侵染，而且对抗性品种仙客1号的影响更为明显。但除了接种Am的处理，大多数处理收获时菌根侵染率仍维持较高的水平(70%以上)。在连作土壤中，感病品种蒙特卡罗接种混合菌种Ri+Am具有较好的抗/耐线虫效应，主要表现为促进植株生长，显著降低根结和卵块数量，但菌根侵染率较灭菌土壤低，约为40%。【结论】综合以上结果，表明菌根化苗能够在一定程度上减轻根结线虫病的危害。土壤灭菌条件下，在感病和抗线虫番茄品种上接种AMF能够减轻线虫的侵染和繁殖，而且在感病品种上的防治效果更加显著。在连作土壤中，在番茄感病品种上接种AMF也表现较好的抗线虫效果。

Abstract:

[Background] Root-knot nematode (RKN) disease is one of main factors constraining tomato production under greenhouse conditions in China. The arbuscular mycorrhizal fungi (AMF) contribute to the control of RKN and the growth of plant. [Objective] The effects of different AMF and combined inoculation on antagonizing the infection and propagation of Meloidogyne incognita were evaluated in two tomato cultivates differing in nematode susceptibility. [Methods] The two cultivars, one of which was susceptible cultivar (Monte Carlo) and the other (Xianke 1) was relatively resistant to root-knot nematode infection, were inoculated respectively by Acaulospora mellea (Am) and Rhizophagus intraradices (Ri) and the mixture of the two AMF species Ri+Am in the sterilized soil before inoculating root-knot nematode, Meloidogyne incognita. The growth of plants and the suppression to nematode infection were investigated. Furthermore, the tomato “Monte Carlo” was inoculated with the mixture of AMF and transplanted in the continuous cropping field soil infested by RKN to evaluate the effects on the growth of tomato and the protective effects against RKN. [Results] The mycorrhizal efficiency of Monte Carlo to inhibit nematodes was greater significantly than that of Xianke 1. Different AMF treatments had different inhibition effects on nematodes. The cultivar of Monte Carlo inoculated by the mixture of two AMF species Ri+Am showed higher protective effects than any single AMF inoculation treatment, while Xianke 1 inoculated by Ri was higher than other treatments. The infection of nematode also greatly influenced AMF colonization, especially to the cultivar Xianke 1. But the AMF colonization of most treatments was still up to 70% in harvest time, except for the species of Am. The tomato “Monte Carlo” inoculated with the mixture of Ri+Am significantly reduced the number of galls and egg masses of RKN in the continuous cropping field soil containing Meloidogyne incognita, comparing to the controls. [Conclusion] The colonization of the mixture of AMF alleviated the infestation of the nematode disease of tomato better than single AMF colonization to a certain degree. The protective effects of susceptible cultivar inoculated with AMF against nematodes were greater than those of the resistant cultivar to nematode.