摘要：

为了在生理和分子水平上初步揭示向日葵对黄萎病的抗性机制,以抗(SC89)、感(LD5009)黄萎病的向日葵品种为材料,测定接种大丽轮枝菌毒素后H₂O₂含量、ROS清除酶(SOD、CAT、POD和PAL)的活性以及抗病信号通路关键基因转录水平的变化。结果表明,接种6 h后H₂O₂在抗病品种SC89中迅速升高,分别在接种大丽轮枝菌毒素12,36 h达到最高值0.55,0.60 μmol/g,随后开始下降,而感病品种中虽然在接种12 h后有一个小的峰值0.17 μmol/g,但是积累水平远远低于抗病品种;ROS清除酶SOD、CAT、POD和PAL活性表现为,抗病品种SC89接种大丽轮枝菌毒素后都在短时间内迅速达到峰值,随后逐渐降低,而感病品种LD5009的峰值低于抗病品种,而且呈现出峰值滞后的现象。同时,接种后抗病信号路径相关基因如Pr5(JA)、Pal(SA)以及ROS清除酶基因如Sod、Sco和Cat转录水平表现为,接种后抗病品种SC89被显著上调。这些结果表明,SA、JA以及H₂O₂等信号分子在向日葵抗黄萎病过程中均发挥着重要的作用。

关键词: 向日葵, 黄萎病, 活性氧, 信号分子

Abstract:

In order to preliminarily reveal the resistance mechanism of sunflower to Verticillium Wilt at the physiological and molecular levels,the resistant sunflower variety SC89 and susceptible variety LD5009 were used as materials,and the content of H₂O₂,the activities of defense enzymes superoxide dismutase(SOD),catalase(CAT),peroxidase(POD)and phenylalanine ammonia lyase(PAL)were measured and the transcription level of key genes in disease resistance signaling pathways were analyzed after the sunflower varieties inoculated with the toxin of Verticillium dahliae.The result showed that H₂O₂ increased rapidly in the resistant variety SC89 at 6 h after inoculation and reached the highest value at 12 h and 36 h,respectively,0.55,0.60 μmol/g,then decline,while in the susceptible variety,although there was a small peak,0.17 μmol/g,at 12 h after inoculation,the accumulation level was far lower than the resistant variety.In the resistant variety,the activity of SOD,CAT,POD and PAL reached the peak rapidly in a short period of time,and then gradually decreased.While the susceptible variety,the peak value of these ROS scavenging enzymes were lower than that of resistant varieties.At the same time,after inoculation,the six disease resistance related genes such as Pr5,Pal and ROS scavenging enzyme gene Sod,Sco and Cat had in varying degrees of induced expression.These results indicated that signal molecules such as SA,JA and H₂O₂ played important roles in the process of sunflower resistance to Verticillium Wilt.

Key words: Sunflower, Verticillium Wilt, ROS, Signaling molecules