根腐病菌侵染对黄芪苯丙烷途径关键酶活性的影响

以蒙古黄芪-根腐病菌（Fusarium solani和F. acuminatum）为互作体系,测定苯丙烷途径关键酶苯丙氨酸解氨酶(PAL)、肉桂酸-4-羟化酶(C4H)及4-香豆酸-辅酶A连接酶(4CL)活性的变化,以期获得黄芪抗根腐病菌侵染机制的信息,为抗病育种工作提供参考。试验采用幼苗浸根法接种病菌,分光光度法测定3种酶的动态变化。结果表明,F. solani侵染黄芪后,PAL和C4H活性与对照相比明显升高,并在7、21天出现2个酶活高峰;4CL活性则随着时间的延长持续上升,7、21天时也显著高于对照。F. acuminatum侵染黄芪后,PAL、C4H和4CL的活性均在21天显著高于对照。可见2种病原菌在侵染黄芪过程中,苯丙烷途径的关键酶被不同程度地激活,但2种病菌激活各酶的时间和规律有所差异,表明黄芪对这2种病菌的抗性机制明显不同。

Effects of Root Rot Pathogens Infection on Key Enzymes in Phenylpropanoid Pathway of Astragalus membranaceus var. mongholicus

In this study, the activity changes of key enzymes in phenylpropanoid pathway including phenylalanine ammonia lyase (PAL), cinnamate 4-hydroxylase (C4H), 4-coumarate:coenzyme A ligase (4CL) were determined to obtain information on the mechanism of Astragalus membranaceus against root rot pathogens, so as to provide reference for disease resistance breeding. Regarding A. membranaceus var. mongholicus and root rot pathogens as the interaction system, the dynamic activity changes of the three enzymes were measured by spectrophotometry methods with the A. membranaceus being inoculated with Fusarium solani and F. acuminatum respectively using the root-dipping method. The results showed that both PAL and C4H in Astragalus infected by F. solani had a significantly higher activity than their counterparts in the control, and both had enzyme activity peaks at 7 d and 21 d, respectively; the activity of 4CL steadily increased with the time and was also significantly higher than that of the control at 7 d and 21 d. In the case of Astragalus infected by F. acuminatum, the activities of all three enzymes in treatment were significantly higher than that in the control at 21 d. It can be seen that during the infection of both pathogens, the key enzymes in phenylpropanoid pathway are activated to some extents, but differ in the time and pattern of being activated, which indicates that A. membranaceus has obvious different disease-resistant mechanisms against the infection of F. solani and F. acuminatum.