title: Kunitz trypsin inhibitor: an antagonist of cell death triggered by phytopathogens and fumonisin b1 in Arabidopsis.
abstract: Programmed cell death (PCD) is a central regulatory process in both plant development and in plant responses to pathogens. PCD requires a coordinate activation of pro-apoptotic factors such as proteases and suppressors inhibiting and modulating these processes. In plants, various caspase-like cysteine proteases as well as serine proteases have been implicated in PCD. Here, we show that a serine protease (Kunitz trypsin) inhibitor (KTI1) of Arabidopsis acts as a functional KTI when produced in bacteria and in planta. Expression of AtKTI1 is induced late in response to bacterial and fungal elicitors and to salicylic acid. RNAi silencing of the AtKTI1 gene results in enhanced lesion development after infiltration of leaf tissue with the PCD-eliciting fungal toxin fumonisin B1 (FB1) or the avirulent bacterial pathogen Pseudomonas syringae pv tomato DC3000 carrying avrB (Pst avrB). Overexpression of AtKTI1 results in reduced lesion development after Pst avrB and FB1 infiltration. Interestingly, RNAi silencing of AtKTI1 leads to enhanced resistance to the virulent pathogen Erwinia carotovora subsp. carotovora SCC1, while overexpression of AtKTI1 leads to higher susceptibility towards this pathogen. Together, these data indicate that AtKTI1 is involved in modulating PCD in plant-pathogen interactions.
authors.affiliation: Viikki Biocenter, Department of Biological and Environmental Sciences, Division of Genetics, University of Helsinki, POB 56, FIN-00014, Helsinki, Finland.
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: Günter
authors.initials: G
authors.lastname: Brader
authors.forename: E Tapio
authors.initials: ET
authors.lastname: Palva
mesh_terms: D000251:Adenosine Triphosphatases / Q000187:drug effects / Q000235:genetics*; D000595:Amino Acid Sequence; D000818:Animals; D007611:Aprotinin / Q000737:chemistry / Q000235:genetics* / Q000494:pharmacology*; D017360:Arabidopsis / Q000187:drug effects* / Q000382:microbiology* / Q000469:parasitology; D029681:Arabidopsis Proteins / Q000187:drug effects / Q000235:genetics*; D016923:Cell Death / Q000187:drug effects*; D037341:Fumonisins / Q000037:antagonists & inhibitors / Q000633:toxicity*; D020868:Gene Silencing; D007113:Immunity, Innate / Q000235:genetics; D000074201:Katanin; D008969:Molecular Sequence Data; D009183:Mycotoxins / Q000037:antagonists & inhibitors / Q000633:toxicity*; D011480:Protease Inhibitors / Q000378:metabolism / Q000494:pharmacology; D034622:RNA Interference; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D018411:Spodoptera / Q000472:pathogenicity; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D029681:Arabidopsis Proteins; D037341:Fumonisins; D009183:Mycotoxins; D011480:Protease Inhibitors; D011994:Recombinant Proteins; C056933:fumonisin B1; D007611:Aprotinin; D000251:Adenosine Triphosphatases; C436244:KTN1 protein, Arabidopsis; D000074201:Katanin