Battle in the dark - Interactions of the fungal pathogen Fusarium culmorum with beneficial microorganisms at the soil-root interface of wheat

这项在美国明尼苏达大学圣保罗分校植物病理系进行的研究，探讨了真菌毒素脱氧雪腐镰刀菌烯醇(DON)在真菌病原菌镰刀菌侵染小麦根部过程中的作用。主要集中在根霉菌和DON与有益的根际细菌，即链霉菌之间的相互作用。此外，还研究了DON和F.culmorum对链霉菌的抑制作用。在体外和植物中进行了分析。本研究的第一阶段表明，除链霉菌外，荧光假单胞菌对小麦根部土传镰刀菌有很强的抑制作用，除镰刀菌外，禾谷镰刀菌是美国大平原上小麦和大麦根腐病和根腐病的主要病原菌。因此，荧光假单胞菌和禾谷镰刀菌分离株将被纳入延长的研究期限。获得的有益根际细菌(Streptomyces spp.)的碳素利用。和荧光假单胞菌(Passomonas spp.)以不同的碳源和浓度为底物，对来自美国大平原上麦田的不同种类和化学类型的镰刀菌进行微量滴定分析。这将有助于解释谷物中抑制性根际细菌和土传病原菌之间的不同拮抗作用。此外，还计划在田间条件下研究DON对小麦根茎基真菌侵染成功的影响。此外，还将用大麦进行DON作为根侵染镰刀菌的致病因子的试验。在受控条件下的实验中，计划分析在产毒镰刀菌感染大麦茎基后，真菌毒素DON是否从茎基转移到大麦籽粒中，这可能是成熟大麦籽粒中霉菌毒素污染的另一个来源。

This ongoing study conducted at the Department of Plant Pathology, University of Minnesota, St. Paul, USA, investigates the role of the mycotoxin deoxynivalenol (DON) during root infections of wheat by the fungal pathogen Fusarium culmorum. The main focus is on the interaction between F. culmorum, DON and beneficial rhizobacteria, i.e. Streptomyces spp.. Further, the suppressive effect of DON and F. culmorum, respectively, to Streptomyces spp. is analysed in vitro and in planta. The first phase of this research suggested that besides Streptomyces spp. fluorescent Pseudomonas species are strong inhibitors of soilborne Fusarium species at wheat roots and that F. graminearum besides F. culmorum is a main contributor to Fusarium Foot and Root Rot of wheat and barley in the Upper Great Plains, USA. Therefore, fluorescent Pseudomonas and F. graminearum isolates will be included into the prolonged research stay. The carbon use of the obtained beneficial rhizobacteria (Streptomyces spp. and fluorescent Pseudomonas spp.) from wheat fields of the Upper Great Plains, USA as well as the different Fusarium species and chemotypes being used in this study, will be analysed in a microtiter assay using different carbon sources and concentrations as substrate. This will serve to explain varying antagonistic interactions between suppressive rhizobacteria and soilborne pathogens in cereals. Additionally, it is planned to study the impact of DON for successful wheat root and stem base infections by F. culmorum under field conditions. Experiments on DON as virulence factor for root infection by Fusarium species will be also conducted with barley. In experiments under controlled conditions it is planned to analyze whether the mycotoxin DON is translocated from the stem basis into barley kernels following stem base infections with toxigenic Fusarium species, which might be an additionally source of mycotoxin contamination of mature barley kernels.