魔芋软腐病发生与根际微生物群落变化响应机制

Amorphophallus konjac has played an important role for industrial structural adjustment in mountainous area country. Planting konjac will help the farmers to become rich. But the soft rot disease of konjac sometimes brings huge economic losses to farmers, which make the farmers in a dilemma whether planting konjac. Based on years of research, the applicant team had found the intrinsic relationship between the variations of rhizosphere microorganisms and the occurrence of soft rot disease, but the response mechanism is not clear. Therefore, based on our research at the biological control of soft rot disease, the infection pathways of soft rot pathogens, rapid detection of the soft rot disease and so on, the differences of the dominant microflora, the different of the functional diversity and genetic diversity for rhizosphere microorganisms of ill or health konjac which planting in imitating the original habitat and field will be studied by the traditional culture and BIOLOG-ECO, PCR-DGGE, illumine Miseq and so on. The dynamics mechanism will be clarified for the konjac rhizosphere microorganisms which planting in imitating the original habitat and field, so we know the relationship between occurrence of soft rot disease and variations of rhizosphere microorganism on konjac. It will provide the new microbial resources for biological control the soft rot disease of konjac. It will also provide the theory basis for reducing the soft rot disease of konjac by the soil microbial regulation. It will have important theoretical and practical significance for promoting the scale planting and improving the yield and quality of konjac.

“小魔芋”在山区农村产业结构调整中扮演着重要角色，对芋农脱贫致富有着显著成效。但软腐病毁灭性破坏又使芋农“望魔兴叹”。申请者多年研究发现，该病害的发生与其根际微生物的变化具有本质联系，但变化机制尚不清楚。因此，本项目在软腐病病害生物防治技术、软腐病菌侵染路径、软腐病快速检测技术等研究基础上，运用传统微生物培养和BIOLOG-ECO、PCR-DGGE、illumina Miseq等生物学技术，研究仿原生境和大田种植的不同年限的健康和发病魔芋根际土壤优势菌群差异，微生物功能多样性和遗传物质多样性，阐明仿原生境和大田种植健康和发病魔芋不同年限根际土壤微生物动态变化机制，明确魔芋软腐病发生与根际土壤微生物群落结构变化的关系，为魔芋软腐病防控提供新的原生态微生物资源，为通过土壤微生物调控降低魔芋软腐病的发生提供微生态防治依据，对促进魔芋规模化种植、提高魔芋产量和品质有重要的理论和实践意义。

魔芋在山区农村产业结构调整中扮演着重要角色，但软腐病毁灭性破坏又使芋农“望魔兴叹”。该病害的发生与其根际微生物的变化具有本质联系，但变化机制不清楚。.运用PCR-DGGE技术研究仿原生境和大田种植的不同年限的健康和发病魔芋根际土壤优势菌群差异，6个细菌门（Proteobacteria, Actinobacteria, Cellulomonadaceae, Acidobacteria, Firmicutes, Gemmatimonadetes）被检测到，Proteobacteria 是在这几个门中最丰富的，Proteobacteria在魔芋生长期间发挥了重要作用；Actinobacteria被用作控制土传和种传病害的生防菌，而Actinobacteria随着魔芋种植年限的变化而变化，表明Actinobacteria对魔芋土壤群落有显著影响。利用BIOLOG-ECO技术研究表明氨基酸、羧酸和其他碳水化合物是微生物利用的主要碳源，连作3年大田种植健康魔芋根际土壤代谢功能多样性最高，这可能是土壤中含有大量致病菌和拮抗微生物引起。.利用illumina Miseq技术研究了大田种植和仿生境种植条件下魔芋根际土壤微生物细菌多样性。研究结果表明，在仿生境栽培条件下，土壤细菌的Shannon多样性指数和Chao 1指数相对稳定；但大田种植条件下其值随着种植年限的增加而增加。相对丰度比大于0.3%的细菌属有44个，种植年限和栽培模式显著影响其中的11个属。连作3年，大田种植和仿生境种植魔芋根际土壤中Luteolibacter 和 Bacteroides差异显著，不同耕作模式对Pseudomonas的影响较大，而种植年限对Myroides的影响较大。仿生境种植改变了土壤细菌群落的结构和组成，导致了有益菌的相对平衡，有益菌的相对平衡有助于减少软腐病的发生。利用illumina Miseq技术研究了连作条件下健康魔芋与发病魔芋根际土壤细菌多样性。相对丰度大于0.3%有44个细菌属，14个细菌属显著受种植年限和魔芋自身状况影响。随着连作的不断增加，Alicyclobacillus减少，而Achromobacter, Lactobacillus, Kaistobacter, Rhodoplanes在连作3年后增加。连作改变了土壤细菌群落的结构和组成，导致有益菌的减少和有害菌的增加。