Leibniz Institute of Vegetable and Ornamental Crops, Theodor-Echtermeyer-Weg 1,14979 Großbeeren, Brandenburg, Germany and Institute of Biology, Plant Physiology Department, Humboldt University of Berlin, Philippstraße 13, 10115 Berlin, Germany.
Department of Plant Anatomy, Institute of Biology, Eötvös Loránd University, Pázmány Péter sétány 1/C, 1117 Budapest, Hungary.
FEMS Microbiol Ecol. 2019 Dec 1;95(12). doi: 10.1093/femsec/fiz164.
Dark septate endophytes (DSEs) present a group of widespread root-colonizing fungi. The role of these endophytes in ecosystems and their interactions with plant pathogens are not well understood. In the current study, we assessed the antagonistic potential of the model DSE Cadophora sp. against the tomato soilborne pathogens Rhizoctonia solani, Pythium aphanidermatum and Verticillium dahliae. To investigate their interactions, we conducted in vitro assays followed by a greenhouse experiments in which tomato plants were inoculated with different combinations of the DSE and pathogens. RNA accumulation of selected tomato pathogenesis-related genes and of Cadophora sp. genes with putative antifungal function was analyzed. Cadophora sp. inhibited the growth of the fungal pathogens in vitro and vice versa; a negative impact of the pathogens on the growth of the DSE was also detected. In roots, however, this mutual negative interaction could not be observed. Expression analyses of plant genes could not explain this differential effect, but among the Cadophora sp. genes analyzed, a gene coding for a chalcone synthase was downregulated in planta. The data indicate that plants can change the interaction between fungi and, therefore, in vitro detected antagonism does not necessarily reflect the situation inside the plant.
深色有隔内生真菌（DSE）是一类广泛存在于植物根部的真菌。这些内生真菌在生态系统中的作用及其与植物病原菌的相互作用尚不清楚。在本研究中，我们评估了模式 DSE Cadophora sp. 对番茄土传病原菌立枯丝核菌、腐霉和黄萎轮枝菌的拮抗潜力。为了研究它们的相互作用，我们进行了体外试验，随后在温室中进行了试验，在温室中，番茄植株被不同组合的 DSE 和病原菌接种。分析了选定的番茄病程相关基因和具有潜在抗真菌功能的 Cadophora sp. 基因的 RNA 积累。Cadophora sp. 在体外抑制真菌病原菌的生长，反之亦然；也检测到病原菌对 DSE 生长的负面影响。然而，在根中，这种相互的负相互作用无法观察到。植物基因的表达分析无法解释这种差异效应，但在分析的 Cadophora sp. 基因中，一个编码查尔酮合酶的基因在植物体内下调。数据表明，植物可以改变真菌之间的相互作用，因此，体外检测到的拮抗作用不一定反映植物内部的情况。
