The accumulation of phenolic compounds and increased activities of related enzymes contribute to early defense against walnut blight

Novel Cucumis enzymes associated with host-specific disease resistance to Phytophthora melonis Katsura

“…However, the physiological pathway by which CAT affects the resistance to P. melonis remains unclear and further investigations are needed. This result is consistent with other studies for Lilium hybrids [22], Juglans [18] and Brassica juncea [49].…”

“…In the present study, systemic induction of PPO expression in the resistant and moderately resistant genotypes in response to P. melonis might provide an additional line of defense to protect cucumber plants against further attack by pathogens. PPOs appear to play a role in the resistance to P. melonis, since the PPO activity was considerably higher in the roots of inoculated plants of resistant genotypes, which is consistent with observations made for cucumber, walnut and common bean plants in which PPO was demonstrated to be induced by Fusarium oxysporum, Xanthomonas arboricola and arbuscular mycorrhizal fungi, respectively [18,57,58]. Additionally, a significant correlation between the antioxidant enzymes indicates the role of the antioxidant enzymes system under P. melonis infection.…”

“…However, no correlation was observed between damping-off susceptibility and CAT activity changes ( Table 2). The CAT enzyme activity displayed different patterns in different genotypes under stress and mainly affects plant disease resistance through two physiological pathways [18]. This is an important H 2 O 2 -scavenging enzyme in plants and is localized in the peroxisomes.…”

“…Polyphenol oxidase (PPO) and peroxidase (POX) are important oxidative enzymes found in most plant species. PPO and POX catalyze the formation of lignin and other oxidative phenols, thereby contributing to the formation of defense barriers by structural reinforcement, to protect against pathogens [18,19]. In cucumber the activities of peroxidase increased following the inoculation with Fusarium oxysporum [20].…”

The comprehensive changes in soil properties are continuous cropping obstacles associated with American ginseng (Panax quinquefolius) cultivation

“…As described above, some phenolic acids may be beneficial to the growth of AG; if so, by what mechanism do these beneficial phenolic acids exert their role? Phenolic acids are produced by plants under external stress [37][38][39][40] . They do have many beneficial functions, such as antibacterial, antioxidant and so on, which can alleviate the stress of plants 41 .…”