间作小麦和接种AM真菌协同提高蚕豆抗枯萎病能力和根际微生物碳代谢活性

【目的】接种丛枝菌根 (arbuscular mycorrhizal，AM) 真菌和间作均是防治蚕豆枯萎病的有效方法，从土壤微生物学角度研究两者协同减轻蚕豆枯萎病的机理，对控制蚕豆枯萎病传播具有重要意义。【方法】利用盆栽试验方法，进行了间作和接种AM真菌摩西管柄囊霉 (Funneliformis mosseae，Fm) 和扭形球囊霉 (Glomus tortuosum，Gt) 试验。设蚕豆单作对照 (MF)、蚕豆小麦间作 (IF)、蚕豆单作接种Fm (MFFm)、蚕豆小麦间作接种Fm (IFFm)、蚕豆单作接种Gt (MFGt)、蚕豆小麦间作接种Gt (IFGt) 6个处理。于蚕豆开花期 (生长70天) 取土壤样品，测定蚕豆幼苗生长、枯萎病发生、根际镰刀菌数量和微生物碳代谢活性。【结果】间作显著增加蚕豆幼苗干重93.0%、降低蚕豆枯萎病病情指数71.4%，接菌显著增加蚕豆幼苗干重55.3%、降低病情指数76.6%，其中接种Fm真菌对蚕豆幼苗干重的影响更大，对病情指数的抑制效果更好。间作接菌显著增加蚕豆幼苗干重100%、降低病情指数89.8%。Biolog微平板测试结果显示，间作提高根际微生物碳代谢活性32.3%；接菌提高微生物活性85.4%；间作接菌提高微生物活性122%。主成分分析结果表明，间作和接菌均明显改变了根际微生物的群落结构，并主要改变了对碳水化合物类、氨基酸和羧酸类碳源的利用。相关性分析结果显示，枯萎病发病率和病情指数与根际镰刀菌数量呈极显著正相关关系，与AWCD值、Shannon多样性指数和丰富度指数均呈极显著负相关。【结论】蚕豆与小麦间作和接菌对抑制蚕豆枯萎病和促进蚕豆生长均具有积极效应，间作显著提高了AM真菌的定殖率，二者协同提高了根际微生物活性，改变了微生物群落结构，并抑制了病原菌增殖，进而控制蚕豆枯萎病发生。

Synergistic effects of intercropping with wheat and inoculation with arbuscular mycorrhizal fungi on improvement of anti-Fusarium wilt and rhizosphere microbial carbon metabolic activity of faba bean

【Objectives】Intercropping and inoculation of arbuscular mycorrhizal fungus (AMF) are effective methods for controlling wilt in faba bean. Exploring the role of AMF and intercropping is the prerequisite for controlling faba bean wilt from soil microbial system.【Methods】A greenhouse pot experiment was conducted using Funneliformis mossea (Fm) and Glomus tortuosum (Gt) as tested AM fungi. Six treatments were included as monocropped faba bean (CK), intercropping of faba bean and wheat (IF), monocropped faba bean with inoculation of Fm or Gt (MFFm or MFGt), intercropping of faba bean and wheat with inoculation of Fm or Gt (IFFm or IFGt). After faba bean grown for 70 days (in flowering stage), soil and plant samples were collected. The faba bean seedling growth, occurance of Fusarium wilt, rhizosphere microbial C metabolic activity in faba bean rhizosphere soil were measured.【Results】In comparison with CK), intercropping significantly increased the dry weight of faba bean seedling by 93.0%, inoculation with AMF by 55.3% and intercropping combine with inoculation by 100%; significantly decreased disease index of faba bean Fusarium wilt by 71.4%, 76.6% and 89.8% respectively. Inoculation of Fm obtained higher dry weight of faba bean seedlings and stronger inhibition of disease index of Fusarium wilt. Studies based on Biolog micro plates showed that intercropping, AMF inoculation, intercropping combining with AMF inoculation increased the average well color development (AWCD value) by 32.3%, 85.4% and 122%. Principal component analyses demonstrated that intercropping, inoculation of AMF, intercropping combining with AMF inoculation changed the rhizospheric microbial community composition obviously, and utilization ability of carbohydrates, amino acids and carboxylic acids carbon sources were significantly increased when intercropping with inoculation AMF. Correlation analyses demonstrated that the disease incidence and index were significantly and positively correlated with the number of F. oxysporum in rhizosphere, and significantly and negatively correlated with AWCD value, Shannon’s diversity index and richness index.【Conclusions】Intercropping with wheat and inoculation of AMF have positive effects on inhibiting Fusarium wilt and promoting the growth of faba bean. The intercropping could significantly increase the colonization rate of AMF, and the combination of the two method could further enhance rhizosphere microbial activity, improve rhizosphere microbial community functional diversity and inhibit the growth of Fusarium oxysporum. As a result, the faba bean plant growth is promoted, and the Fusarium wilt occurrence is reduced drastically.