Earth and Life Institute, Mycology, Université catholique de Louvain (UCL), Louvain-la-Neuve, Belgium.
FEMS Microbiol Ecol. 2011 Sep;77(3):558-67. doi: 10.1111/j.1574-6941.2011.01135.x. Epub 2011 Jun 28.
Trichoderma sp. is a biocontrol agent active against plant pathogens via mechanisms such as mycoparasitism. Recently, it was demonstrated that Trichoderma harzianum was able to parasitize the mycelium of an arbuscular mycorrhizal (AM) fungus, thus affecting its viability. Here, we question whether this mycoparasitism may reduce the capacity of Glomus sp. to transport phosphorus ((33)P) to its host plant in an in vitro culture system. (33)P was measured in the plant and in the fungal mycelium in the presence/absence of T. harzianum. The viability and metabolic activity of the extraradical mycelium was measured via succinate dehydrogenase and alkaline phosphatase staining. Our study demonstrated an increased uptake of (33)P by the AM fungus in the presence of T. harzianum, possibly related to a stress reaction caused by mycoparasitism. In addition, the disruption of AM extraradical hyphae in the presence of T. harzianum affected the (33)P translocation within the AM fungal mycelium and consequently the transfer of (33)P to the host plant. The effects of T. harzianum on Glomus sp. may thus impact the growth and function of AM fungi and also indirectly plant performance by influencing the source-sink relationship between the two partners of the symbiosis.
木霉属（Trichoderma sp.）是一种通过寄生等机制对植物病原体起防治作用的生防菌。最近的研究表明，哈茨木霉（Trichoderma harzianum）能够寄生丛枝菌根（AM）真菌的菌丝，从而影响其活力。在这里，我们质疑这种寄生现象是否会降低球囊霉属（Glomus sp.）在体外培养系统中向其宿主植物转运磷（(33)P）的能力。在存在/不存在哈茨木霉的情况下，测量了植物和真菌菌丝中的(33)P。通过琥珀酸脱氢酶和碱性磷酸酶染色测量了外生菌丝的活力和代谢活性。我们的研究表明，在存在哈茨木霉的情况下，AM 真菌对(33)P 的吸收增加，这可能与寄生引起的应激反应有关。此外，在存在哈茨木霉的情况下，AM 外生菌丝的破坏影响了(33)P 在 AM 真菌菌丝内的转运，从而影响了(33)P 向宿主植物的转移。因此，哈茨木霉对球囊霉属的影响可能会影响 AM 真菌的生长和功能，并通过影响共生体两个伙伴之间的源库关系间接影响植物的性能。
