Splivallo Richard, Novero Mara, Bertea Cinzia M, Bossi Simone, Bonfante Paola
Department of Plant Biology, University of Torino, CEBIOVEM Centre of Excellence, Viale Mattioli 25, 10125 Torino, Italy.
IPP-CNR, Viale Mattioli 25, 10125 Torino, Italy.
New Phytol. 2007;175(3):417-424. doi: 10.1111/j.1469-8137.2007.02141.x.
The function of fungal volatiles in fungal-plant interactions is poorly understood. The aim here was to address this lack of knowledge, focusing on truffles, ectomycorrhizal fungi that are highly appreciated for their aroma. The effect of volatiles released by truffles was tested on Arabidopsis thaliana in a closed chamber bioassay. The volatiles produced by Tuber melanosporum, Tuber indicum and Tuber borchii fruiting bodies inhibited A. thaliana in terms of root length and cotyledon leaf size, and in some cases induced a bleaching of the seedlings, thus indicating toxicity. Ten synthetic volatiles were tested in a similar way. The strongest inhibitory effect was observed with C(8) molecules such as 1-octen-3-ol, an alcohol with a typical 'fungal smell'. Two of these C(8) compounds were further tested to investigate their mechanism of action. 1-Octen-3-ol and trans-2-octenal induced an oxidative burst (hydrogen peroxide, H(2)O(2)) in the A. thaliana leaves as well as a strong increase in the activities of three reactive oxygen species (ROS)-scavenging enzymes. These results demonstrate that fungal volatiles inhibit the development of A. thaliana and modify its oxidative metabolism. Even though limited to laboratory observations, these results indicate the presence of a hitherto unknown function of fungal volatiles as molecules that mediate fungal-plant interactions.
真菌挥发物在真菌与植物相互作用中的功能尚不清楚。本文旨在解决这一知识空白，重点研究松露，即因其香气而备受青睐的外生菌根真菌。在封闭箱生物测定中，测试了松露释放的挥发物对拟南芥的影响。黑孢块菌、印度块菌和勃氏块菌子实体产生的挥发物在根长和子叶大小方面抑制了拟南芥，在某些情况下还导致幼苗白化，从而表明具有毒性。以类似方式测试了十种合成挥发物。观察到具有最强抑制作用的是C(8)分子，如1-辛烯-3-醇，一种具有典型“真菌气味”的醇类。进一步测试了其中两种C(8)化合物以研究其作用机制。1-辛烯-3-醇和反式-2-辛烯醛在拟南芥叶片中诱导了氧化爆发（过氧化氢，H(2)O(2)）以及三种活性氧（ROS）清除酶的活性大幅增加。这些结果表明真菌挥发物抑制了拟南芥的发育并改变了其氧化代谢。尽管仅限于实验室观察，但这些结果表明真菌挥发物作为介导真菌与植物相互作用的分子存在一种迄今未知的功能。
