硫色镰刀菌(Fusarium sulphureum)接种对抗病/易感品种马铃薯块茎苯丙烷代谢的影响比较

Comparison of Phenylpropanoid Pathway Metabolism in Slices of Susceptible and Resistant Potato Cultivars Inoculated with Fusarium sulphureum

以抗病品种"青薯168"和易感品种"陇薯3号"马铃薯块茎为试材,比较2个品种马铃薯块茎、切片接种硫色镰刀菌(F.sulphureum)后苯丙烷代谢关键酶活性和相关产物积累的动态变化。结果表明,"青薯168"马铃薯块茎及其切片接种F.sulphureum后的病斑直径显著小于"陇薯3号"。2个品种马铃薯接种F.sulphureum后,在前期苯丙氨酸解氨酶(PAL)、4-香豆酰-辅酶A连接酶(4CL)活性以及总酚、类黄酮含量增加,但随着病斑的扩展,PAL、4CL活性以及总酚、类黄酮含量迅速降低并低于未接菌对照。肉桂酸-4-羟化酶(C4H)活性和木质素含量在整个培养过程中均显著低于未接菌对照。抗病品种"青薯168"接种F.sulphureum后,PAL、4CL和C4H活性以及总酚、类黄酮和木质素含量均显著高于"陇薯3号"。表明苯丙烷代谢在F.sulphureum与马铃薯块茎互作的早期发挥了积极的作用,一旦病斑开始扩展,苯丙烷代谢的抗病作用将显著降低;抗病块茎的苯丙烷代谢活性显著高于感病块茎,表明苯丙烷代谢在马铃薯块茎抗干腐病方面具有重要的作用。

Comparative analysis between two potato cultivars was carried out to detect the key enzymes activities and metabolite accumulation in phenylpropanoid pathway in whole and sliced potatoes inoculated with Fusarium sulphureum. The results showed that lesion diameters on tubers and slices of the resistant cultivar 'Qingshu No.168' inoculated with F. sulphureum were significantly smaller than those of the susceptible cultivar 'Longshu No.3'. The activities of phenylalanine ammonia-lyase(PAL) and 4-coumarate A ligase(4CL), and the contents of total phenolics and flavonoids in inoculated slices of both potato cultivars increased at early stages of infection but decreased sharply with the enlargement of lesions, reaching levels lower than in the control at later stages of infection. However, the activity of cinnamate 4-hydroxylase(C4H) and the content of lignin were lower than in the control over the entire culture period. The activities of PAL, 4CL, and C4 H, and the contents of total phenolics, flavonoids and lignin in inoculated slices of 'Qingshu No.168' were higher than those of 'Longshu No.3'. These findings suggested that phenylpropanoid metabolism played a positive role at early stages of F. sulphureumpotato interaction; however, the resistance role of phenylpropanoid metabolism decreased with the expansion of dry rot, and the activities of phenylpropanoid metabolism in slices of the resistant potato cultivar were significantly higher than in the susceptible one, indicating that phenylaprapanoid metabolism plays an important role in resistance of potato tubers against F. sulphureum.