Role of Polyphenol Oxidase, Peroxidase, Phenylalanine Ammonia Lyase, Chlorogenic Acid, and Total Soluble Phenols in Resistance of Potatoes to Soft Rot

Abstract

Pectobacterium atrosepticum (Pa), P. carotovorum subsp. brasiliensis (Pcb) and Dickeya spp. cause soft rot of potato 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 eleven 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 Ngadze, E. Plant Disease 2 Mondial Zw . 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 w i t h h i g h P P O a n d P A L e n z y m e a c t i v i t y a s w e l l a s i n c r e a s e d c o n c e n t r a t i o n s o f 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.

Biochemical Characterization of Compatible Plant Virus Interaction: A Case Study with Bunchy Top Virus-Banana Host-Pathosystem

“…Upon infection by pathogens, the host phenolic compounds may increase and contribute to enhance the mechanical strength of host cell walls by the synthesis of lignin and suberin that are involved in the formation of physical barriers that can block the spread of pathogens (Ngadze et al, 2012;Singh et al, 2014). In the present study, the amount of total phenol was significantly higher in virus infected leaves (Fig.…”

“…4b). Total soluble phenols together with PPO play a role in resistance to viral pathogens (Thipathi and Verma, 1975;Kumar et al, 1991;Li and Steffens, 2002;Ngadze et al, 2012).…”

Biocontrol of Sclerotium rolfsii in Groundnut by Using Microbial Inoculants

“…Also, the phenolic compounds are known to be inhibitorier against infective agents (Kumar et al, 2010). The increased accumulation of phenolic compounds reflects increased lignification indicates possible bio-protection in plants (Ngadze, 2012). The improvement in total phenols activities by AM and Trichoderma inoculations with increased growth has been reported in common bean, Brassica oleraacea var.…”

Polyphenol oxidase and lysozyme mediate induction of systemic resistance in tomato, when a bioelicitor is used

“…This acid inhibits the cell wall degrading-activity of Pectobacterium sp. (Ngadze et al 2012). Upon challenge with P. syringae pv.…”