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

Abstract

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.

Inducible expression of the gene of Zinnia elegans coding for extracellular ribonuclease in Nicotiana tabacum plants

“…It was reported that RNase activity was higher in diseased (Green 1994, Lusso and Kuc 1995, Galiana et al 1997, Hugot et al 2002, Šindelářová et al 2002, Šindelář and Šindelářová 2005 and mechanically wounded plants (Ye and Droste 1996, Lers et al 1998, LeBrasseur et al 2002. Recently it was shown that the Capsicum chinense PR-4 protein does not have chitinase activity, as previously proposed for PR-4 proteins, instead, it has both RNase and DNase activity (Guevara-Morato et al 2010). …”

Identification of a cluster of PR4-like genes involved in stress responses in rice

“…The PR4 protein genes identified for the first time were named win-1 and win-2, which are tandemly located on the potato genome and encode two wound-inducible proteins with high homology to each other (Stanford et al, 1989). Since then, a number of PR4 protein genes have been identified from different plant species such as tomato, tobacco, Arabidopsis, Chinese cabbage, wheat, Capsicum chinense, and maize (Linthorst et al, 1991;Caruso et al, 1993;Potter et al, 1993;Bravo et al, 2003;Park et al, 2005;Guevara-Morato et al, 2010).…”

Detection and partial characterization of a putative closterovirus affecting Ficus carica: molecular, ultrastructural and physiological aspects of infected leaves

“…The supernatant of protein samples containing about 25 lg proteins was loaded onto gel wells. Arrowheads are pointing to absent or present of polypeptides due to virus infection reported in other works(Radwan et al 2007;Elvira et al 2008;Guevara-Morato et al 2010). Plants responded to pathogen attack by formation of new families of proteins called PRs.…”