Characterization of a pathogenesis-related protein 4 (PR-4) induced in Capsicum chinense L3 plants with dual RNase and DNase activities.
Resistance conferred by the L(3) gene is active against most of the tobamoviruses, including the Spanish strain (PMMoV-S), a P(1),(2) pathotype, but not against certain strains of pepper mild mottle virus (PMMoV), termed as P(1),(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.
Environmental Biology Department, CIB, CSIC, C/Ramiro de Maeztu no. 9, E-28040 Madrid, Spain.
Maria Angeles
MA
Guevara-Morato
Mario García
MG
de Lacoba
Isabel
I
García-Luque
Maria Teresa
MT
Serra
D002212:Capsicum / Q000201:enzymology* / Q000235:genetics / Q000821:virology; D003001:Cloning, Molecular; D003851:Deoxyribonucleases / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D010935:Plant Diseases / Q000235:genetics / Q000821:virology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D017863:Potexvirus / Q000472:pathogenicity*; D017434:Protein Structure, Tertiary; D018749:RNA, Plant / Q000235:genetics; D012260:Ribonucleases / Q000235:genetics / Q000378:metabolism*; D020539:Sequence Analysis, Protein
D010940:Plant Proteins; D018749:RNA, Plant; C053376:pathogenesis-related proteins, plant; D003851:Deoxyribonucleases; D012260:Ribonucleases