The pepper extracellular peroxidase CaPO2 is required for salt, drought and oxidative stress tolerance as well as resistance to fungal pathogens.
In plants, biotic and abiotic stresses regulate the expression and activity of various peroxidase isoforms. Capsicum annuum EXTRACELLULAR PEROXIDASE 2 (CaPO2) was previously shown to play a role in local and systemic reactive oxygen species bursts and disease resistance during bacterial pathogen infection. Here, we report CaPO2 expression patterns and functions during conditions of biotic and abiotic stress. In pepper plants, CaPO2 expression was strongly induced by abscisic acid, but not by defense-related plant hormones such as salicylic acid, ethylene and jasmonic acid. CaPO2 was also strongly induced by abiotic and biotic stress treatments, including drought, cold, high salinity and infection by the hemibiotrophic fungal pathogen Colletotrichum coccodes. Loss-of-function of CaPO2 in virus-induced gene silenced pepper plants led to increased susceptibility to salt- and osmotic-induced stress. In contrast, CaPO2 overexpression in transgenic Arabidopsis thaliana plants conferred enhanced tolerance to high salt, drought, and oxidative stress, while also enhancing resistance to infection by the necrotrophic fungal pathogen Alternaria brassicicola. Taken together, these results provide evidence for the involvement of pepper extracellular peroxidase CaPO2 in plant defense responses to various abiotic stresses and plant fungal pathogens.
Laboratory of Molecular Plant Pathology, School of Life Sciences and Biotechnology, Korea University, Anam-dong, Sungbuk-ku, Seoul 136-713, Republic of Korea.
Hyong Woo
HW
Choi
Byung Kook
BK
Hwang
D000040:Abscisic Acid / Q000494:pharmacology; D000222:Adaptation, Physiological / Q000187:drug effects / Q000235:genetics; D000528:Alternaria / Q000187:drug effects / Q000502:physiology; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000382:microbiology / Q000502:physiology; D002212:Capsicum / Q000201:enzymology* / Q000382:microbiology* / Q000502:physiology; D020231:Colletotrichum / Q000187:drug effects / Q000502:physiology*; D060467:Disease Resistance / Q000187:drug effects; D055864:Droughts; D005110:Extracellular Space / Q000187:drug effects / Q000201:enzymology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D020868:Gene Silencing / Q000187:drug effects; D017343:Genes, Plant / Q000235:genetics; D009995:Osmosis / Q000187:drug effects; D018384:Oxidative Stress / Q000187:drug effects; D044742:Peronospora / Q000187:drug effects / Q000502:physiology; D009195:Peroxidase / Q000235:genetics / Q000378:metabolism*; D010935:Plant Diseases / Q000382:microbiology; D018515:Plant Leaves / Q000166:cytology / Q000187:drug effects / Q000235:genetics / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics
D010940:Plant Proteins; D012333:RNA, Messenger; D012965:Sodium Chloride; D000040:Abscisic Acid; D009195:Peroxidase