title: Narrow-Leafed Lupin (Lupinus angustifolius) β1- and β6-Conglutin Proteins Exhibit Antifungal Activity, Protecting Plants against Necrotrophic Pathogen Induced Damage fromSclerotinia sclerotiorumandPhytophthora nicotianae.
abstract: Vicilins (7S globulins) are seed storage proteins and constitute the main protein family in legume seeds, particularly in narrow-leafed lupin (Lupinus angustifoliusL.; NLL), where seven vicilin genes, called β1- to β7-conglutin have been identified. Vicilins are involved in germination processes supplying amino acids for seedling growth and plant development, as well as in some cases roles in plant defense and protection against pathogens. The roles of NLL β-conglutins in plant defense are unknown. Here the potential role of five NLL β-conglutin family members in protection against necrotrophic fungal pathogens was investigated and it was demonstrated that recombinant purified 6xHis-tagged β1- and β6-conglutin proteins exhibited the strongestin vitrogrowth inhibitory activity against a range of necrotrophic fungal pathogens compared to β2, β3, and β4 conglutins. To examine activityin vivo, two representative necrotrophic pathogens, the fungusSclerotinia sclerotiorumand oomycetePhytophthora nicotianaewere used. Transient expression of β1- and β6-conglutin proteins inNicotiana benthamianaleaves demonstratedin vivogrowth suppression of both of these pathogens, resulting in low percentages of hyphal growth and elongation in comparison to control treated leaves. Cellular studies using β1- and β6-GFP fusion proteins showed these conglutins localized to the cell surface including plasmodesmata. Analysis of cellular death followingS. sclerotiorumorP. nicotianaerevealed both β1- and β6-conglutins suppressed pathogen induced cell deathin plantaand prevented pathogen induced suppression of the plant oxidative burst as determined by protein oxidation in infected compared to mock-inoculated leaves.
authors.affiliation: The Institute of Agriculture, The University of Western Australia, PerthWA, Australia; Department of Biochemistry, Cell and Molecular Biology of Plants, Estacion Experimental del Zaidin, Spanish National Research CouncilGranada, Spain.
authors.forename: Jose C
authors.initials: JC
authors.lastname: Jimenez-Lopez
authors.affiliation: Centre for Environment and Life Sciences, Agriculture and Food, Commonwealth Scientific and Industrial Research Organisation, Floreat WA, Australia.
authors.forename: Su
authors.initials: S
authors.lastname: Melser
authors.affiliation: The Institute of Agriculture, The University of Western Australia, PerthWA, Australia; Centre for Environment and Life Sciences, Agriculture and Food, Commonwealth Scientific and Industrial Research Organisation, FloreatWA, Australia.
authors.forename: Kathleen
authors.initials: K
authors.lastname: DeBoer
authors.affiliation: Centre for Environment and Life Sciences, Agriculture and Food, Commonwealth Scientific and Industrial Research Organisation, Floreat WA, Australia.
authors.forename: Louise F
authors.initials: LF
authors.lastname: Thatcher
authors.affiliation: The Institute of Agriculture, The University of Western Australia, PerthWA, Australia; Centre for Environment and Life Sciences, Agriculture and Food, Commonwealth Scientific and Industrial Research Organisation, FloreatWA, Australia.
authors.forename: Lars G
authors.initials: LG
authors.lastname: Kamphuis
authors.affiliation: Centre for Environment and Life Sciences, Agriculture and Food, Commonwealth Scientific and Industrial Research Organisation, Floreat WA, Australia.
authors.forename: Rhonda C
authors.initials: RC
authors.lastname: Foley
authors.affiliation: The Institute of Agriculture, The University of Western Australia, PerthWA, Australia; Centre for Environment and Life Sciences, Agriculture and Food, Commonwealth Scientific and Industrial Research Organisation, FloreatWA, Australia.
authors.forename: Karam B
authors.initials: KB
authors.lastname: Singh
keywords: 7S globulins; fungal pathogen; legume; oxidative stress; plant defense; seed storage protein; vicilins