马铃薯土传黑痣病拮抗菌的根际行为特征研究

由立枯丝核菌（Rhizoctonia solani）侵染形成的马铃薯黑痣病已成为马铃薯生产中发病最严重的土传病害，连作加剧这一病害的发生。我们前期研究发现，连作条件下马铃薯根系分泌物的改变以及病原菌在根际的富集是病害发生的主要原因，施用辅以马铃薯立枯丝核菌拮抗菌的生物有机肥可有效降低黑痣病的发病率和病薯率，并可显著改变根际的微生物区系，但其作用机理尚不完全清晰。本项目通过土培和水培试验，对筛选到的对立枯丝核菌有强烈拮抗作用的类芽孢杆菌（Paenibacillus jamilae，QHZ11）菌株进行绿色荧光蛋白（GFP）标记，利用激光共聚焦扫描显微镜（CLSM）和扫描电子显微镜（SEM）等技术，研究GFP标记的QHZ11–gfp菌株在马铃薯根表和根际的定殖特征，以及马铃薯根系分泌物与拮抗菌的相互作用，为生产上采用生防措施克服马铃薯土传病害的技术途径提供理论依据。

Black scurf disease (stem canker) of potatoes caused by rhizoctonia solani has become the most serious soil-borne disease which has been limiting the potato production in Gansu Province. Continous potato monocropping has deteriorated the disease. Our previous researches showed that the component change of root exudate and the enrichment of pathogen fungi in potato rhizosphere were the main causes of the disease. The bioorganic fertilizer containing antagonistic bacteria (Paenibacillus jamilae QHZ11) against potato rhizoctonia solani has been shown to suppress the incidence of the disease, and change the microbial community diversities and taxa abundances in potato rhizosphere significantly, but whose mechanism is not clear. In this study, the colonization patterns of Paenibacillus jamilae QHZ11 tagged by green fluorescence protein (GFP) on potato rhizoplane and in rhizosphere was investigated in hydroponic and natural soil system by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM), and the interactions between root exudates and antagonistic bacteria were also studied, both of which could provide the theoretical basis for the practical application of QHZ11 for the suppression of potato black scurf disease.