Ernst Michael, Mendgen Kurt W, Wirsel Stefan G R
Lehrstuhl Phytopathologie, Fachbereich Biologie, Universität Konstanz, Universitätstr. 10, D-78457 Konstanz, Germany.
Mol Plant Microbe Interact. 2003 Jul;16(7):580-7. doi: 10.1094/MPMI.2003.16.7.580.
Fungal endophytes mainly belong to the phylum Ascomycota and colonize plants without producing symptoms. We report on the isolation of seed-borne fungal endophytes from Phragmites australis (common reed) that were ascribed to the genus Stagonospora. Nested polymerase chain reaction (PCR) assays revealed that a Stagonospora sp. regularly colonized reed as shown for a period of three years. In spring, it was only detected in roots, whereas in autumn, it could frequently be found in all organs, including seeds. Microcosm experiments revealed that seeds harbored viable propagules of the fungus that colonized the developing germling, indicating vertical transmission. Endophytic growth was confirmed by immunofluorescence microscopy, reisolation of the fungus after surface sterilization, and PCR. Aseptic microcosms were established for studying fungal contributions towards host vitality. Several Stagonospora isolates enhanced reed biomass. Seed-borne endophytic Stagonospora spp. thus can provide improved vigor to common reed, which could be most important when seed-derived germlings establish new reed stands.
真菌内生菌主要属于子囊菌门，它们定殖于植物体内却不产生症状。我们报告了从芦苇中分离出的种子携带的真菌内生菌，这些内生菌被归为壳针孢属。巢式聚合酶链反应（PCR）分析表明，一种壳针孢属真菌在三年时间里持续定殖于芦苇。春季时，仅在根部检测到该真菌，而秋季时，在包括种子在内的所有器官中都能频繁发现它。微观实验表明，种子携带了该真菌的活繁殖体，这些繁殖体定殖于发育中的幼苗，表明存在垂直传播。通过免疫荧光显微镜、表面消毒后真菌的再分离以及PCR证实了内生生长。建立了无菌微观环境来研究真菌对宿主活力的贡献。几种壳针孢分离株增加了芦苇的生物量。因此，种子携带的内生壳针孢属真菌能够提高芦苇的活力，这在种子来源的幼苗建立新的芦苇群落时可能最为重要。
