![]() A multitude of other proteases from various plants are up-regulated during infection by pathogens, suggesting a potential role in plant defense ( Tornero et al., 1997 Avrova et al., 1999, 2004 Liu et al., 2001 Guevara et al., 2002 Zhao et al., 2003 Tian et al., 2004). Interestingly, knockout of VPE γ in Arabidopsis results in increased susceptibility to Botrytis cinerea and Turnip mosaic virus, suggesting that VPEs not only contribute to resistance to avirulent pathogens but also to basal defense to pathogens during susceptible interactions ( Rojo et al., 2004). Plant vacuolar processing enzymes (VPEs) were recently identified to be Cys proteases with caspase-like activity (cleavage after Asp residues) that are essential for virus-induced HR and virus resistance ( Hatsugai et al., 2004 Rojo et al., 2004). Inhibition of PCD using caspase inhibitors pointed to a role of plant proteases with caspase-like activity in the HR ( D'Silva et al., 1998 Solomon et al., 1999 Chichkova et al., 2004 van der Hoorn and Jones, 2004). Proteasome complexes involved in the ubiquitin-mediated protein degradation pathway have been implicated in PCD and disease resistance ( Suty et al., 2003 Tor et al., 2003 Zeng et al., 2004). The multiple roles of proteases in plant defense are also reflected in their involvement in the hypersensitive response (HR), a form of programmed cell death (PCD) that is associated with resistance to pathogens ( D'Silva et al., 1998 Solomon et al., 1999 Mosolov et al., 2001 Chichkova et al., 2004). An apoplastic aspartic protease (AP) CDR1 from Arabidopsis ( Arabidopsis thaliana) activates defense signaling probably by generating an unknown mobile endogenous peptide elicitor ( Xia et al., 2004). Rcr3, a secreted Cys protease from tomato ( Lycopersicon esculentum), is required for resistance mediated by the Cf-2 receptor-like protein against strains of the fungus Cladosporium fulvum that carry the Avr2 avirulence gene ( Kruger et al., 2002). For example, several apoplastic proteases have been linked to defense. There is emerging evidence that the proteolytic machinery of plants plays important and diverse roles in defense against pathogens. Altogether, this and earlier studies suggest that interplay between host proteases of diverse catalytic families and pathogen inhibitors is a general defense-counterdefense process in plant-pathogen interactions. Characterization of PIP1 revealed that it is a PR protein closely related to Rcr3, a tomato apoplastic cysteine protease that functions in fungal resistance. Biochemical functional analyses revealed that EPIC2B interacts with and inhibits a novel papain-like extracellular cysteine protease, termed Phytophthora Inhibited Protease 1 (PIP1). infestans, and were up-regulated during infection of tomato, suggesting a role during P. Among these, the epiC1 and epiC2 genes lacked orthologs in Phytophthora sojae and Phytophthora ramorum, were relatively fast-evolving within P. ![]() infestans secreted proteins with similarity to cystatin-like protease inhibitor domains. Here, we describe EPIC1 to EPIC4, a new family of P. Among these, EPI1 and EPI10 bind and inhibit the pathogenesis-related (PR) P69B subtilisin-like serine protease of tomato. Previously, we described a family of 14 Kazal-like extracellular serine protease inhibitors from P. ![]() The oomycete pathogen Phytophthora infestans, the agent of the devastating late blight disease of tomato ( Lycopersicon esculentum) and potato ( Solanum tuberosum), has evolved an arsenal of protease inhibitors to overcome the action of host proteases. There is emerging evidence that the proteolytic machinery of plants plays important roles in defense against pathogens.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |