壳聚糖对山药连作障碍的消减及对其根际微生物的调节

When Yam plants were cropped continiously, diseases and insect pests occured significantly, yield discreased greatly which is named by continuous cropping obstacle, which is bad for yam developping high efficiently and sustainably. The way of biological organic fertilizer can improve the rhizosphere microorganisms, reduce yam continuous cropping obstacle to some extent, but the control effect is still not ideal. Previous research showed that, disease index is closely related to rhizosphere microorganisms community. Chitosan is widespread in Marine biological shell of shrimp, crab, it could adjust rhizosphere microorganisms and enzyme activities, increase crop resistance to disease, reduce all kinds of diseases including continuous cropping obstacle. At the same time, chitosan is safe, convenient and environment friendly. The misequencing technology can analyze microbial community, abundance comprehensively and accurately. So, this project would use misequencing technology to study the prevention of continuous cropping obstacle and regulation of rhizosphere microorganisms by chitosan in yam, would reveal the relationship between rhizosphere microorganisms and disease index, physical and chemical properties, enzyme activity in soil, and the microorganism machanism of chitosan reducing yam continuous cropping obstacle, build soil microorganism standards for health yam rhizosphere microflora and its regulation method by chitosan.

山药连作时病虫害多发，减产严重，表现出明显的连作障碍，严重影响了山药的品质和经济效益，生物有机肥措施可一定程度地改善根际微生物种群，减轻山药连作障碍，但目前的防治效果还不理想。前期研究表明，连作病害的病情指数与根际微生物种群结构关系密切。壳聚糖广泛存在于海洋生物虾蟹的外壳中，可调节根际微生物种群和生物酶活性，提高花生、香蕉、番木瓜、苹果和烟草等作物的抗逆性，减轻连作障碍和各种病害，且安全、便捷、环保。高通量测序技术能全面、准确、快速地反映微生物群落的组成、丰度。因此，本项目拟借助MiSeq高通量测序技术，研究壳聚糖对山药连作障碍的消减及对其根际微生物群落结构的调节，揭示根际微生物群落结构与病情指数和土壤理化生物性状之间的关系和壳聚糖消减山药连作障碍的根际微生物机理，探明健康山药根际微生物区系的标准及壳聚糖调控方法。

山药连作时病虫害多发，减产严重，表现出明显的连作障碍，严重影响了山药的品质和经济效益。前期研究表明，连作病害的病情指数与根际微生物种群结构关系密切。壳聚糖广泛存在于海洋生物虾蟹的外壳中，可调节根际微生物种群和生物酶活性，提高花生、香蕉、番木瓜、苹果和烟草等作物的抗逆性，减轻连作障碍和各种病害，且安全、便捷、环保。.本项目借助MiSeq高通量测序技术，结合形态学和生理生化学，研究了壳聚糖、壳寡糖及其与链霉菌联合等不同壳聚糖处理对山药连作障碍的消减及对其根际微生物群落结构的调节。结果得出，不同壳聚糖处理通过综合作用减轻了连作山药病情和根结线虫发展，提高了防治效果，降低了减产幅度，消减了山药连作障碍；发现不同壳聚糖处理均能破坏病原菌结构，抑制病原菌扩繁，调节山药根际微生物群落结构，调节土壤理化和生物学性状，提升植株防御酶活性，调节植株相关基因表达量；防治效果与防御酶及土壤性状之间，相互联系，相互影响；壳聚糖和链霉菌之间有正交互效应。初步得出，壳聚糖及其与链霉菌联合处理可以调节连作山药的土壤性状，达到减轻山药连作障碍的效果。