苎麻连作障碍发生与根际微生物群落结构的相关性研究

Abstract: Ramie is the fiber crop with Chinese characteristics. At present, as the planting area of ramie decreased greatly, economic benefit is reduced, which are bottlenecks to the development of ramie industry, one of the main reasons is the continuous cropping obstacle. The study of ramie continuous cropping obstacle had not been reported yet. Our team have been the first confirmed that the occurrence period of ramie continuous cropping obstacle and defined the main impact factors are the root-lesion nematode, rhizosphere microorganisms and rhizosphere autotoxic compounds. Based on previous research，This study will analyze the acting mechanisms of rhizosphere microorganisms to continuous cropping obstacle on ramie by adopting the combination of high throughput sequencing and traditional culture method, to analyze rhizosphere fungi and bacteria community structure and species of ramie continuous cropping obstacle among four different ramie producing areas in the Yangtze river basin, to clarify the key driving factors of change of rhizosphere microorganisms in ramie continuous cropping obstacles through the analysis of the interactions with the environment. Screening and identification the rhizosphere microorganism activity strains, draw up a cultivation technique to reduce or eliminate the continous cropping obstacles of ramie on the basis of synthesizing various factors. This research will provide cultivation technique and theoretical basis for solve the big problem of ramie continuous cropping obstacle in production, improving the yield and quality of ramie in China, is of great significance to promote the sustainable development of ramie industry.

苎麻是具有中国特色的以纤维为主要用途的作物。目前，苎麻种植面积下降，经济效益降低，给苎麻产业的发展带来瓶颈，其主要原因之一是连作障碍。关于苎麻连作障碍的研究较少，为此，申请者团队前期初步探明了苎麻连作障碍发生时期，明确连作障碍主要影响因子为根腐线虫害、根系自毒物、根际微生物等因子，并对根腐线虫、根系自毒物开展了深入研究。在前期研究基础上，本项目将针对根际微生物对苎麻连作障碍的作用机理进行剖析，采用高通量测序和传统培养相结合的方法，分析长江流域江四个不同苎麻主产区连作障碍苎麻根际微生物的群落结构和种类，通过与环境的互作分析，阐明驱动连作障碍苎麻根际微生物变化的关键因子；筛选、鉴定抗苎麻连作障碍的根际微生物活性菌株，制定缓解苎麻连作障碍的栽培措施，本研究将为解决苎麻连作障碍这个生产上的大难题提供理论基础和栽培技术，为提高我国苎麻产量和品质，促进苎麻产业的可持续发展具有重要意义。

苎麻是具有中国特色的以纤维为主要用途的作物。目前，苎麻种植面积下降，经济效益降低，给苎麻产业的发展带来瓶颈，其主要原因之一是连作障碍。关于苎麻连作障碍的研究较少，为此，申请者团队前期初步探明了苎麻连作障碍发生时期，明确连作障碍主要影响因子为根腐线虫害、根系自毒物、根际微生物等因子，并对根腐线虫、根系自毒物开展了深入研究。本项目按照计划书采用高通量测序和传统培养相结合的方法，分析长江流域四个不同苎麻主产区连作障碍苎麻根际微生物的群落结构和种类，通过与环境的互作分析，阐明了驱动连作障碍苎麻根际微生物门类为厚壁菌门、变形菌门和酸杆菌门，厚壁菌门的丰度与苎麻产量成正相关，其中芽孢杆菌、乳球菌、克氏杆菌、肠球菌和嗜碱菌是丰度较高的根际微生物，这些微生物种类与苎麻的生长相关；通过宏基因组进一步筛选获得了缓解苎麻连作障碍的主要微生物种类为根瘤菌、慢生性根瘤菌及抗生素溶杆菌等，为进一步研制根际菌缓解苎麻连作障碍提供了可供选择的根际菌种类。结合不同地区连作苎麻多样性和宏基因组分析结果，筛选了一批芽孢杆菌用于苎麻的连作障碍缓解和促生，通过盆栽和大田施菌试验一共筛选了6个具有促生作用的芽孢杆菌，并对这其中4个菌进行了基因组鉴定，对施菌后的苎麻植株进行了全株代谢组分析和根际土壤多样性分析，明确施菌后能促进苎麻中榭皮苷、甜菜碱、胡萝卜酸等物质的改变，进一步的说明这些芽孢杆菌对苎麻具有一定的促生作用，在缓解苎麻连作障碍中起作用，本研究为解决苎麻连作障碍这个生产上的大难题提供了几个具有促生、缓解苎麻连作障碍的根际芽孢杆菌，未来进一步的将这些菌开发利用，为提高我国苎麻产量和品质，促进苎麻产业的绿色可持续发展提供较好的基础。