title: Aspergillus infection inhibits the expression of peanut 13S-HPODE-forming seed lipoxygenases.
abstract: Oxylipins recently have been implicated as signaling molecules for cross-kingdom communication in plant-pathogen interactions. Linoleic acid and its two plant lipoxygenase (LOX) oxylipin products 9- and 13-hydroperoxy fatty acids (9S- and 13S-HPODE) have been shown to have a significant effect on differentiation processes in the mycotoxigenic seed pathogens Aspergillus spp. Whereas both fatty acids promote sporulation, 9S-HPODE stimulates and 13S-HPODE inhibits mycotoxin production. Additionally, Aspergillus flavus infection of seed promotes linoleate 9-LOX expression and 9S-HPODE accumulation. Here, we describe the characterization of two peanut seed lipoxygenase alleles (PnLOX2 and PnLOX3) highly expressed in mature seed. PnLOX2 and PnLOX3 both are 13S-HPODE producers (linoleate 13-LOX) and, in contrast to previously characterized 9-LOX or mixed function LOX genes, are repressed between 5-fold and 250-fold over the course of A. flavus infection. The results of these studies suggest that 9S-HPODE and 13S-HPODE molecules act as putative susceptibility and resistance factors respectively, in Aspergillus seed-aflatoxin interactions.
authors.affiliation: Department of Plant Pathology, University of Wisconsin-Madison, Madison 53706, USA.
authors.forename: Dimitrios I
authors.initials: DI
authors.lastname: Tsitsigiannis
authors.forename: Susan
authors.initials: S
authors.lastname: Kunze
authors.forename: David K
authors.initials: DK
authors.lastname: Willis
authors.forename: Ivo
authors.initials: I
authors.lastname: Feussner
authors.forename: Nancy P
authors.initials: NP
authors.lastname: Keller
mesh_terms: D001230:Aspergillus / Q000502:physiology*; D001483:Base Sequence; D017931:DNA Primers; D008041:Linoleic Acids / Q000096:biosynthesis*; D008054:Lipid Peroxides / Q000096:biosynthesis*; D008084:Lipoxygenase / Q000187:drug effects* / Q000235:genetics; D010944:Plants / Q000196:embryology / Q000201:enzymology*; D012150:Polymorphism, Restriction Fragment Length; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012639:Seeds / Q000201:enzymology*
chemical_list: D017931:DNA Primers; D008041:Linoleic Acids; D008054:Lipid Peroxides; C038649:13-hydroperoxy-9,11-octadecadienoic acid; D008084:Lipoxygenase