Plant sesquiterpenes induce hyphal branching in arbuscular mycorrhizal fungi
Plant sesquiterpenes induce hyphal branching in arbuscular mycorrhizal fungi
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DOI：
10.1038/nature03608
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发表时间：
2005-06-09
期刊：
影响因子：
64.8
通讯作者：
Hayashi, H
中科院分区：
文献类型：
--
作者：
Akiyama, K;Matsuzaki, K;Hayashi, H
丛枝菌根（AM）真菌与超过80%的陆地植物的根形成互利共生关系（1）。真菌在没有宿主根的情况下无法完成其生命周期。它们的孢子可以在没有寄主的情况下萌发和生长，但它们的菌丝生长非常有限。关于AM真菌与其宿主植物之间的信号传导和识别的分子机制知之甚少。在宿主识别的第一阶段之一中，AM真菌的菌丝在形成附着胞（用于穿透植物根的结构）之前在宿主根附近显示出广泛的分支（2-4）。已知宿主根释放触发菌丝分支的信号分子（5-7），但这些分支因子尚未被分离。在这里，我们从百脉根分泌物中分离出一种分支因子，并利用光谱分析和化学合成将其鉴定为独脚金内酯，5-脱氧独脚金醇。独脚金内酯是一组倍半萜内酯，先前分离为寄生杂草独脚金和列当的种子萌发刺激剂（8）。天然独脚金内酯5-脱氧独脚金醇，高粱内酯和独脚金醇，和一个合成的类似物，GR 24，诱导广泛的菌丝分枝在萌发的孢子中的AM真菌Gigaspora margarita在非常低的浓度。
Arbuscular mycorrhizal (AM) fungi form mutualistic, symbiotic associations with the roots of more than 80% of land plants(1). The fungi are incapable of completing their life cycle in the absence of a host root. Their spores can germinate and grow in the absence of a host, but their hyphal growth is very limited. Little is known about the molecular mechanisms that govern signalling and recognition between AM fungi and their host plants. In one of the first stages of host recognition, the hyphae of AM fungi show extensive branching in the vicinity of host roots before formation of the appressorium(2-4), the structure used to penetrate the plant root. Host roots are known to release signalling molecules that trigger hyphal branching(5-7), but these branching factors have not been isolated. Here we have isolated a branching factor from the root exudates of Lotus japonicus and used spectroscopic analysis and chemical synthesis to identify it as a strigolactone, 5-deoxy-strigol. Strigolactones are a group of sesquiterpene lactones, previously isolated as seed-germination stimulants for the parasitic weeds Striga and Orobanche(8). The natural strigolactones 5-deoxy-strigol, sorgolactone and strigol, and a synthetic analogue, GR24, induced extensive hyphal branching in germinating spores of the AM fungus Gigaspora margarita at very low concentrations.