苎麻根际自毒物质及病原物在连作障碍中的作用及缓解机制研究

Ramie is one of the most important economic crops of china,nowadays, at present, 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 occurrence regularity and screening of the gene related to continuous cropping obstacle had not been reported yet at home and abroad.our group have been the first studied that time of continuous cropping obstacle on ramie for recently many years, confirmed that the occurrence period of ramie continuous cropping obstacle and defined the main impact factors are the root-lesion nematode and rhizosphere autotoxic compounds. Based on previous research，This study will analyze ramie rhizosphere autotoxic compounds of different years in continuous cropping, classifying deeply by pathogenic bacteria of rhizosphere soil on ramie continuous cropping obstacle, extracting and screning excellent rhizosphere bacteria from continuous cropping soil which will used to release the continous cropping obstacles on ramie. Building the rotation model of garlic – ramie, draw up a production cultivation technique of release the continous cropping obstacles on 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, in order to improve the yield and quality of ramie in China, is of great significance to promote the sustainable development of ramie industry.

苎麻是我国特有的以纤维为主要用途的经济作物。目前，苎麻种植面积大幅度下降，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，申请者团队前期开展了苎麻连作障碍发生规律的研究，初步探明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危害、根系有毒分泌物等因子。在前期研究基础上，本项目将针对不同连作年限苎麻根际自毒物质进行剖析；对连作苎麻根际土壤病原菌进行深入的种群分类，提取苎麻根际菌并筛选优良菌制成菌剂缓解苎麻连作障碍；建立大蒜-苎麻轮作模式；综合各因素制定一套缓解苎麻连作障碍的栽培技术应用于生产。本研究将为解决苎麻连作障碍这个生产上的大难题提供栽培技术和理论基础，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。

苎麻是我国特有的以纤维为主要用途的经济作物。目前，苎麻种植面积大幅度下降，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，为此本团队前期开展了苎麻连作障碍发生规律的研究，初步探明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危害、根系有毒分泌物等因子。本项目按照计划书主要针对根系、土壤自毒代谢产物及其与微生物怎样影响苎麻连作障碍开展了深入研究。通过连作与非连作苎麻根系、土壤的代谢组分析，获得了与苎麻连作障碍相关的差异代谢自毒产物主要为磷酸盐、半胱氨酰甘氨酸、硫氰酸苄酯、苏糖醇、甘油和2-脱氧赤藓醇等物质，为缓解苎麻连作障碍这个苎麻生产上的大难题提供了新的突破口；并对不同种植区域连作苎麻主要影响根际微生物种类开展了研究，获得了影响苎麻连作障碍的主要影响微生物门类有厚壁菌门、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，这些微生物影响苎麻的生长；采用宏基因组分析了连作障碍苎麻主要影响根际微生物种类并结合自毒代谢产物进行了关联分析，通过宏基因组筛选获得了缓解苎麻连作障碍的主要有益微生物种类为根瘤菌、慢生性根瘤菌及抗生素溶杆菌，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；利用大蒜对苎麻有促生效果的化感作用，开展了大蒜套种苎麻栽培模式的研究，改善土壤结构和微生物群落结构缓解了苎麻的连作障碍，恢复了苎麻的产量的同时还增加了大蒜的产量，具有更高的经济效益。这种种植方法已经申请国家发明专利。通过本项目的研究为解决苎麻连作障碍这个生产上的大难题提供新的突破和理论基础，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。