丛枝菌根真菌对番茄信号物质的诱导效应

盆栽番茄Lycopersicon esculentum幼苗分别接种丛枝菌根(AM)真菌摩西球囊霉Glomus mosseae、地表球囊霉G.versiforme、根内球囊霉G.intraradices、幼套球囊霉G.etunicatum及珠状巨孢囊霉Gigaspora margarita 35d后,开始测定番茄植株内源信号物质水杨酸(SA)、茉莉酸(JA)、一氧化氮(NO)和过氧化氢(H2O2)含量变化,抗性相关酶活性,丙二醛(MDA)含量以及生长量等指标。结果表明,接种AM真菌增加了番茄植株鲜重、株高、地上部和地下部干重、叶片和根系NO、JA、H2O2含量和结合态SA含量,其中,以摩西球囊霉G.mosseae诱导作用最大,叶片和根系内NO、JA、H2O2和结合态SA含量分别比对照增加了3.3和1.9倍、6.8和8.0倍、0.9和1.2倍、1.9和2.6倍,而根系中游离态SA含量一直处于较低水平,只有摩西球囊霉G.mosseae处理在诱导高峰时根系游离态SA含量比对照略有增加。接种AM真菌处理的番茄叶片和根系超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、苯丙氨酸解氨酶(PAL)活性显著增加,其中以摩西球囊霉G.mosseae的诱导效应最大,与未接种对照相比分别增加了0.6和0.3倍、7.9和3.1倍、0.4和1.2倍、2.3和1.9倍;幼套球囊霉G.etunicatum的诱导效应最小:与未接种对照相比分别增加了0.26和0.14倍、2.3和1.0倍、0.1和0.28倍、0.55和0.31倍;而MDA含量下降,分别降低了66%和68%、34%和41%、51%和50%、12%和26%、18%和29%。表明AM真菌能诱导植物同时产生多种信号物质,而且这些信号参与了AM真菌-番茄共生体系统抗性的表达。

Induction of tomato signal substances by arbuscular mycorrhizal fungi

In order to evaluate the induction of plant signal substances by arbuscular mycorrhizal (AM) fungi, a pot experiment by using Lycopersicon esculentum seedlings inoculated with Glomus mosseae, G. versiforme, G. etunicatum, G. intraradices and Gigaspora margarita was carried out. The content of endogenous salicylic acid (SA), jasmonic acid (JA), nitrogen monoxide (NO) and hydrogen peroxide (H2O2), the related resistant enzyme activity, and malondialdehyde (MDA) contents in tomato seedlings were determined in 35 days after inoculation. The results showed that AM fungal inoculation increased significantly the seedling growth (plant fresh weight, plant height, shoot and root dry weight), SA, JA, NO, H2O2 and SA glucosidate content in roots and leaves. The maximum induction effects occurred in G. mosseae and the content of NO, JA, H2O2 and SA glucosidate in leaves and roots had increased by 4.3 and 2.9 times, 7.8 and 9 times, 1.9 and 2.2 times, and 2.9 and 3.6 times respectively over the control. The free SA content in mycorrhizal plants was lower than that in control, but the content in plant treated with G. mosseae was a little higher than that in the control at induction peak. Superoxide dismutase (SOD), peroxidase (POD), phenylalanine ammonia-lyase (PAL) and peroxide catalase (CAT) activities in mycorrhizal plants were greater than those in control. G. mosseae gave the maximum induction effectiveness, and the activity of SOD, POD, CAT, and PAL in roots and leaves had increased by 1.6 and 1.3 times, 8.9 and 4.1 times, 1.4 and 2.2 times, 3.3 and 2.9 times as compared with the control; the G. etunicatum gave the minimum induction effectiveness, and the activity of SOD, POD, CAT and PAL in roots and leaves had increased to 0.26 and 0.14 times, 2.3 and 1.0 times, 0.1 and 0.28 times, 0.55 and 0.31 times as compared with the control; MDA content reduced by 66% and 68%, 34% and 41%, 51% and 50%, 12% and 26%, 18% and 29% as compared with the control. It was concluded that AM fungi could simultaneously induce many plant signal substances, and these signal substances were involved in the resistant expression in AM fungi-tomato symbiont.