西南喀斯特山区连作半夏根际微生物组成与块茎病害关联性研究

半夏是西南喀斯特山区道地药材和助力脱贫攻坚的重点中药材。由于连作障碍，生产上须每年更换种植地块，限制了种植规模和市场供应能力，阻碍了当地中药材产业的可持续发展。根际微生物群落结构失衡引发土传病害加重被认为是药用植物连作障碍的一个主要原因。据报道，块茎干腐和软腐病是西南喀斯特山区半夏的主要病害。然而，连作时，两种病害如何变化，对块茎产量有多大影响；根际微生物群落组成怎样变化，与块茎病害有无关联，目前均不清楚。因此，本项目拟在西南喀斯特山区不同半夏产区布置连作实验，监测半夏块茎病害的发生状况和根际微生物群落组成随连作年限的变化规律，在分离鉴定病原菌和产IAA、ACC脱氨酶、铁载体等促生细菌的基础上，结合盆栽实验，揭示连作半夏根际微生物群落组成尤其是病原菌及促生细菌丰度变化与块茎病害的关联性，及其对块茎产量的影响，为从根际微生物生态学角度深入研究西南喀斯特山区半夏连作障碍的发生机制提供科学依据。

Pinellia ternata is one of the genuine medicinal herb materials, and has been selected as one of the key economic crops to facilitate the poverty alleviation in the Karst mountain area of southwestern China. However, due to severe replanting problem, its total planting area and supply capacity are limited, which consequently prevents the sustainable development of traditional Chinese medicine industry in this area. Some of previous study attributed the replanting problem of medicinal plants to sever plant disease caused by community-structure disorder of rhizospheric microorganisms. Tuber dry rot and soft rot are two severe disease of P. ternata cultivated in the Karst mountain area of southwestern China. Nevertheless, it’s still unknown so far that with an increase in replanting year of P. ternata how these two tuber diseases will develop and subsequently affect tuber yield, and what kind of changes in the community composition of rhizospheric microorganisms will happen and whether they correlate with the tuber diseases. Accordingly, field experiments are planning to set up at different production areas of P. ternata in the Karst mountain area of southwestern China, both tuber disease and the community composition of rhizospheric microorganisms will be monitored yearly during the 3-year study period. Additionally, plant growth-promoting rhizobacteria (PGPB) that can excrete indole-3-acetic acid (IAA), 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase, and/or siderophore will be isolated from the rhizosphere of P. ternata, and identified. After that, a pot-culture experiment in which P. ternata plants are planning to be inoculated with phytopathogens, PGPB, and the combination of these two groups of microbes will be conducted to assess the correlations between community composition of rhizospheric microorganisms and tuber diseases of P. ternata, and its effects on tuber yield. This study aims to provide basic knowledge, from the perspective of microbial ecology in the rhizosphere, for the further research on underlying mechanisms of replanting problem of P. ternata in the Karst mountain area of southwestern China.