Characterization of a pathogenesis-related protein 4 (PR-4) induced in Capsicum chinense L³ plants with dual RNase and DNase activities

• Published in: Journal of experimental botany Vol. 61; no. 12; pp. 3259 - 3271
• Main Authors: Guevara-Morato, Maria Ángeles, de Lacoba, Mario García, García-Luque, Isabel, Serra, Maria Teresa
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01.07.2010
• Subjects: Biological and medical sciences; Capsicum - enzymology; Capsicum - genetics; Capsicum - virology; Capsicum chinense; Cloning, Molecular; compatible interaction; Deoxyribonucleases - genetics; Deoxyribonucleases - metabolism; DNase activity; Fundamental and applied biological sciences. Psychology; HR-induction; incompatible interaction; Models, Molecular; necrogenic interaction; Plant Diseases - genetics; Plant Diseases - virology; Plant Proteins - genetics; Plant Proteins - metabolism; PMMoV; Potexvirus - pathogenicity; PR-4 protein; Protein Structure, Tertiary; Research Papers; Ribonucleases - genetics; Ribonucleases - metabolism; RNA, Plant - genetics; RNase activity; Sequence Analysis, Protein; Incompatibility; PR-4 protein; Enzyme; necrogenic interaction; Esterases; Ribonuclease; Pathogenesis related protein; HR-induction; RNase activity; incompatible interaction; DNase activity; Deoxyribonuclease I; Dicotyledones; compatible interaction; Angiospermae; Botany; Capsicum chinense; Hydrolases; Flavoring crop; Spermatophyta; Solanaceae; Compatibility; PMMoV
• ISSN: 0022-0957; 1460-2431
• DOI: 10.1093/jxb/erq148

Resistance conferred by the L³ gene is active against most of the tobamoviruses, including the Spanish strain (PMMoV-S), a P₁,₂ pathotype, but not against certain strains of pepper mild mottle virus (PMMoV), termed as P₁,₂,₃ pathotype, such as the Italian strain (PMMoV-I). PMMoV-S induces a hypersensitive reaction (HR) in C. chinense PI159236 plant leaves with the formation of necrotic local lesions and restriction of the virus at the primary infection sites. In this paper, a C. chinense PR-4 protein induced during both the compatible and the incompatible interactions has been identified. It was strongly associated with HR induction and to a lesser extent with the compatible interaction, but only in the later stages of infection. Moreover, it was found to accumulate during the necrogenic reaction induced by Potato virus X. The C. chinense PR-4 protein belongs to the PR-4 protein subgroup II, based on the absence of a hevein domain. Furthermore, it is shown that the purified protein does not have chitinase activity, as previously proposed for PR-4 proteins. Instead, it has both RNase and DNase activity, although its contribution to the bulk activity of nucleases in infected plants is very low.