中文摘要：

菌根菌丝桥是植物间在地下进行物质交流的通道，但它能否作为植物间地下化学通讯的通道来传递抗病信号则缺乏研究．本文利用丛枝菌根真菌（AMF）摩西球囊霉在供体与受体番茄植株间建立菌丝桥，对供体植株接种早疫病病原菌茄链格孢菌，研究供体与受体番茄植株根系间是否存在抗病信号的传递．荧光定量PCR检测表明，AMF侵染后的供体番茄植株再接种病原菌，其根系中苯丙氨酸解氨酶基因（PAL）、脂氧合酶基因（LOX）和几丁质酶基因（PR3）的转录水平显著高于仅接种病原菌、未接种病原菌和AMF，以及只接种AMF的番茄植株．更重要的是，与供体有菌丝桥连接的受体番茄根系中刚￡、LOX和PR3的基因的表达量也显著高于无菌丝桥连接、菌丝桥连接被阻断以及有菌丝桥连接但供体植物未接种病原菌的处理，3个基因最高转录水平达到无菌丝桥连接对照受体植物的4．2、4．5和3．5倍．此外，供体植株根系启动防御反应的时间（18和65h）比受体（100和140h）早．表明病原菌诱导番茄供体根系产生的抗病信号可以通过菌丝桥传递到受体根系．

英文摘要：

Common mycorrhizal networks （CMNs） are the underground condmts ot nutrient exchange between plants. However, whether the CMNs can serve as the underground conduits of chemical communication to transfer the disease resistance signals between plants are unknown. By inoculating arbuscular mycorrhizal fungus （AMF） Glomus mosseae to establish CMNs between ＇ donor＇ and ＇ receiver＇ tomato plants, and by inoculating Alternaria solani, the causal agent of tomato early blight disease, to the ＇ donor＇ plants, this paper studied whether the potential disease resistance signals can be transferred between the ＇donor＇ and ＇receiver＇ plants roots. The real time RT-PCR analysis showed that after inoculation with A. solani, the AMF-inoculated ＇ donor＇ plants had strong expression of three test defense-related genes in roots, with the transcript levels of the phenylalanine ammonia-lyase （PAL）, lipoxygenase （LOX） and chitinase （PR3） being signifi- cantly higher than those in the roots of the ＇ donor＇ plants only inoculated with A. solani, not inoc ulated with both A. solani and AMF, and only inoculated with AMF. More importantly, in the presence of CMNs, the expression levels of the three genes in the roots of the ＇ receiver＇ plants were significantly higher than those of the ＇ receiver＇ plants without CMNs connection, with the connec- tion blocking, and with the connection but the ＇ donor＇ plants not A. solani-inoculated. Comparedwith the control （without CMNs connection）, the transcript level of the PAL, LOX and PR3 in the roots of the ＇ receiver＇ plants having CMNs connection with the ＇ donor＇ plants was 4.2-, 4.5- and 3.5-fold higher, respectively. In addition, the ＇ donor＇ plants activated their defensive responses more quickly than the ＇receiver＇ plants （18 and 65 h vs. 100 and 140 h）. These findings sugges- ted that the disease resistance signals could be transferred to the ＇receiver＇ produced by the pathogen-induced ＇ donor＇ tomato pl