丛枝菌根菌丝网络介导的番茄植株根系间抗虫系统性信号的传递

Transfer of systemic signaling of insect resistance between roots of tomato plant through arbuscular mycorrhizal networks

利用丛枝菌根真菌摩西管柄囊霉(Funneliformis mosseae,Fm)在供体与受体番茄根系间建立菌根菌丝网络,研究供体植株叶片被斜纹夜蛾取食诱导产生的抗虫系统防御信号可否通过菌根菌丝网络传递到受体根系,诱导受体植株根系产生防御反应.q-PCR分析表明,预先接种菌根菌Fm的供体植株被斜纹夜蛾取食后,其根系中丙二烯氧化物环化酶基因(AOC)、脂氧合酶基因(LOXD)、蛋白酶抑制剂Ⅰ和Ⅱ基因(PI-Ⅰ和PI-Ⅱ)转录水平显著高于仅被害虫取食和仅接种Fm的处理,以及既未接种Fm又未被害虫取食的对照.同时,与供体有菌根菌丝网络连接的受体植株根系中AOC、LOXD、PI-Ⅰ和PI-Ⅱ转录水平显著高于无菌根菌丝网络连接、菌根菌丝网络连接被阻断,以及有菌根菌丝网络连接但供体植物叶片未被害虫取食的处理,这4个基因最高转录水平分别为无菌丝网络连接对照受体植物的19.5、11.7、9.0、19.0倍.可见,斜纹夜蛾为害叶片可产生系统性防御信号,诱导供体根系产生抗虫防御反应,并且通过菌根菌丝网络将防御信号传递到邻近健康受体番茄根系.

Common mycorrhizal networks(CMNs)between roots of two tomato plants in the same pot were established with arbuscu-lar mycorrhizal fungus Funne/i/ormis mosseae(Fm).We challenged a‘donor5 plant with caterpillar 5po^ojo^era Htura,and investigated the potential transfer of systemic signaling of insect resistance between roots of‘donor’and‘receiver’plants via established CMNs,which leads to induction of defense responses in‘receiver’roots.Real-time q-PCR analyses showed that the transcript levels of allene oxide cyclase(AOC),lipoxygenase(LOXD)and protease inhibitors I and n(P/-I,P/-n)in the roots of Fm preinoculated‘donor’plants were significantly higher after caterpillar feeding as compared with those in the roots of‘donor’plants without Fm inoculation(no CMNs),S./kura damage,or both(control).Furthermore,the transcript levels of 40C,LOXD,P/-I and P/-n in the roots of‘receiver’plant that was connected with a 5./i^ura-attacked‘donor’plant through CMNs were significantly higher than those in the other three control treatments,and induced 19.5,11.7,9.0 and 19.0-fold as compared with those in the roots of‘receiver’plants without CMNs connection with‘donor’plants.These results suggest that the systemic defense signals produced in 5./i^ura-attacked‘donor’leaves can be transferred to‘donor’roots and then be transferred to the‘receiver’roots via CMNs.