Key Laboratory of Ecological Agriculture, Ministry of Agriculture, South China Agricultural University, Guangzhou, China.
PLoS One. 2010 Oct 13;5(10):e13324. doi: 10.1371/journal.pone.0013324.
Plants can defend themselves to pathogen and herbivore attack by responding to chemical signals that are emitted by attacked plants. It is well established that such signals can be transferred through the air. In theory, plants can also communicate with each other through underground common mycorrhizal networks (CMNs) that interconnect roots of multiple plants. However, until now research focused on plant-to-plant carbon nutrient movement and there is no evidence that defense signals can be exchanged through such mycorrhizal hyphal networks. Here, we show that CMNs mediate plant-plant communication between healthy plants and pathogen-infected tomato plants (Lycopersicon esculentum Mill.). After establishment of CMNs with the arbuscular mycorrhizal fungus Glomus mosseae between tomato plants, inoculation of 'donor' plants with the pathogen Alternaria solani led to increases in disease resistance and activities of the putative defensive enzymes, peroxidase, polyphenol oxidase, chitinase, β-1,3-glucanase, phenylalanine ammonia-lyase and lipoxygenase in healthy neighbouring 'receiver' plants. The uninfected 'receiver' plants also activated six defence-related genes when CMNs connected 'donor' plants challenged with A. solani. This finding indicates that CMNs may function as a plant-plant underground communication conduit whereby disease resistance and induced defence signals can be transferred between the healthy and pathogen-infected neighbouring plants, suggesting that plants can 'eavesdrop' on defence signals from the pathogen-challenged neighbours through CMNs to activate defences before being attacked themselves.
植物可以通过对被攻击植物释放的化学信号做出反应来防御病原体和食草动物的攻击。众所周知，这些信号可以通过空气传播。理论上，植物也可以通过地下共同菌根网络（CMNs）相互通信，这些网络将多株植物的根部连接在一起。然而，到目前为止，研究主要集中在植物间的碳营养物质移动上，没有证据表明防御信号可以通过这种菌根菌丝网络进行交换。在这里，我们表明 CMNs 介导了健康植物和被病原体感染的番茄植物（Lycopersicon esculentum Mill.）之间的植物间通讯。在番茄植物之间与丛枝菌根真菌 Glomus mosseae 建立 CMNs 后，用病原体茄丝核菌（Alternaria solani）对“供体”植物进行接种，导致健康邻近“受体”植物的抗病性和假定防御酶（过氧化物酶、多酚氧化酶、几丁质酶、β-1,3-葡聚糖酶、苯丙氨酸解氨酶和脂氧合酶）的活性增加。当连接着受到 A. solani 挑战的“供体”植物的 CMNs 连接着未感染的“受体”植物时，这些未感染的“受体”植物也激活了六个防御相关基因。这一发现表明，CMNs 可能作为植物间地下通讯的导管，在健康和受病原体感染的邻近植物之间传递抗病性和诱导防御信号，这表明植物可以通过 CMNs 从受病原体攻击的邻居“偷听”防御信号，在自身受到攻击之前激活防御。
