Conversion from mutualism to parasitism: a mutant of the ectomycorrhizal agaricomycete Tricholoma matsutake that induces stunting, wilting, and root degeneration in seedlings of its symbiotic partner, Pinus densiflora, in vitro
Conversion from mutualism to parasitism: a mutant of the ectomycorrhizal agaricomycete Tricholoma matsutake that induces stunting, wilting, and root degeneration in seedlings of its symbiotic partner, Pinus densiflora, in vitro
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DOI：
10.1139/cjb-2019-0060
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发表时间：
2019-08-01
期刊：
影响因子：
1.1
通讯作者：
Ohta, Akira
中科院分区：
文献类型：
--
作者：
Murata, Hitoshi;Nakano, Shota;Ohta, Akira
松茸口蘑是一种外生菌根木耳菌，与针叶树一起产生松茸蘑菇。在这里，我们在伽玛射线照射松茸NBRC 33136后分离出一个多性突变体G1。除了表现出增加纤维素和直链淀粉降解活性和改变菌丝形态外，G1还使侧根退化，并导致其共生伙伴松（Pinus densiflora）的幼苗发育迟缓或致命萎蔫。先前在氩离子束照射后分离的突变体Ar 59表现出与G1相同的表型，但没有其有害影响。与NBRC 33136一样，ar59在健康的皮层细胞周围形成了一个由单胚芽菌丝组成的Hartig网。在g1接种的幼苗中，Hartig网由穿透细胞间隙的大量捆绑菌丝组成，并伴有一些不寻常的植物皮质细胞形式。rRNA基因相关标记序列，包括4个单核苷酸多态性，在NBRC 33136、G1和Ar 59中100%相同，表明它们是野生型突变体。因此，伽马射线照射可以将真菌从有益的转化为有害的。这些发现表明，真菌基因组中存在一种未知的机制，可以将共生转化为寄生。
Tricholoma matsutake is an ectomycorrhizal agaricomycete that produces matsutake mushrooms in association with conifers. Here, we isolated a pleiotropic mutant, designated as G1, following gamma-ray irradiation of T. matsutake NBRC 33136. In addition to exhibiting increased cellulose-and amylose-degrading activities and altered mycelial morphology, G1 degenerated lateral roots and caused stunting or fatal wilting of seedlings of its symbiotic partner, Pinus densiflora, in vitro. A mutant, designated Ar 59, previously isolated after argon-ion beam irradiation, exhibited the same phenotypes as G1, but without its detrimental effects. Ar 59, like NBRC 33136, developed a Hartig net around healthy cortical cells that was composed of uniseriate hyphae. In G1-inoculated seedlings, the Hartig net was composed of heavily bundled hyphae penetrating the intercellular space, and it was accompanied by somewhat unusual forms of plant cortical cells. Sequences of rRNA gene-related markers, including four single nucleotide polymorphisms present within each strain, were 100% identical among NBRC 33136, G1, and Ar 59, indicating that they are mutants of the wild-type. Thus, gamma-ray irradiation can convert the fungus from a beneficial to a harmful agent. These findings suggest the presence of an unknown mechanism in the fungal genome that can transform mutualism into parasitism.