Ngadze Elizabeth, Icishahayo David, Coutinho Teresa A, van der Waals Jacquie E
Department of Microbiology and Plant Pathology, University of Pretoria, Pretoria, 0002, South Africa, and Department of Crop Science, University of Zimbabwe, P.O. Box MP167, Mount Pleasant Harare, Zimbabwe.
Department of Crop Science, University of Zimbabwe, P.O. Box MP167, Mount Pleasant Harare, Zimbabwe.
Plant Dis. 2012 Feb;96(2):186-192. doi: 10.1094/PDIS-02-11-0149.
Pectobacterium atrosepticum, P. carotovorum subsp. brasiliensis, and Dickeya spp. cause soft rot of potato (Solanum tuberosum) worldwide. Plants respond to bacterial invasion by activating defense responses associated with accumulation of several enzymes and inhibitors, which prevent pathogen infection. This study focused on the role of polyphenol oxidase (PPO), peroxidase (POD), phenylalanine ammonia lyase (PAL), chlorogenic acid, and total soluble phenols in imparting resistance to soft rot pathogens. Seven and 11 varieties grown by farmers in South Africa and Zimbabwe, respectively, were used in the study. The results showed significantly higher (P < 0.001) enzyme activity of PPO and PAL as well as higher concentrations of chlorogenic acid and total soluble phenols in Vanderplank, Pentland Dell, M69/11, Romano, M59/20, and Mondial. PAL activity increased significantly with time in all varieties, and the highest activity was recorded 8 h after cutting. The resistance of the varieties was correlated with high PPO and PAL enzyme activity as well as increased concentrations of chlorogenic acid and total soluble phenols. PPO, POD, and PAL activities increased significantly in wounded and inoculated tubers. These findings show that PAL, PPO, POD, chlorogenic acid, and total soluble phenols play a role in imparting resistance to potato soft rot infection.
黑胫果胶杆菌、胡萝卜软腐果胶杆菌巴西亚种和迪基氏菌在全球范围内都会引发马铃薯（茄属）软腐病。植物通过激活与多种酶和抑制剂积累相关的防御反应来应对细菌入侵，这些酶和抑制剂可防止病原体感染。本研究聚焦于多酚氧化酶（PPO）、过氧化物酶（POD）、苯丙氨酸解氨酶（PAL）、绿原酸和总可溶性酚类在赋予马铃薯对软腐病原体抗性方面的作用。该研究分别使用了南非和津巴布韦农民种植的7个和11个品种。结果表明，在范德普朗克、彭特兰戴尔、M69/11、罗马诺、M59/20和蒙迪阿尔品种中，PPO和PAL的酶活性显著更高（P < 0.001），绿原酸和总可溶性酚类的浓度也更高。在所有品种中，PAL活性均随时间显著增加，切割后8小时记录到最高活性。品种的抗性与高PPO和PAL酶活性以及绿原酸和总可溶性酚类浓度的增加相关。在受伤和接种的块茎中，PPO、POD和PAL活性显著增加。这些发现表明，PAL、PPO、POD、绿原酸和总可溶性酚类在赋予马铃薯对软腐感染的抗性中发挥作用。
