Two closely related members of Arabidopsis 13‐lipoxygenases (13‐LOXs), LOX3 and LOX4, reveal distinct functions in response to plant‐parasitic nematode infection. (28th January 2014)

• Record Type: Journal Article
• Authors: Ozalvo, Rachel; Cabrera, Javier; Escobar, Carolina; Christensen, Shawn A.; Borrego, Eli J.; Kolomiets, Michael V.; Castresana, Carmen; Iberkleid, Ionit; Brown Horowitz, Sigal
• Is Part Of: Molecular plant pathology. Volume 15:Number 4(2014:May)
• Page Start: 319
• Page End: 332
• Publication Date: 2014-01-28
• Subjects: Plant diseases -- Molecular aspects -- Periodicals; Plant-pathogen relationships -- Molecular aspects -- Periodicals; 571.936
• DOI: 10.1111/mpp.12094
• Languages: English
• ISSNs: 1464-6722

Abstract

<abstract abstract-type="main"> <title>Summary</title> <p>The responses of two closely related members of <italic>Arabidopsis</italic> 13‐lipoxygenases (13‐LOXs), LOX3 and LOX4, to infection by the sedentary nematodes root‐knot nematode (<italic>Meloidogyne javanica</italic>) and cyst nematode (<italic>Heterodera schachtii</italic>) were analysed in transgenic <italic>Arabidopsis</italic> seedlings. The tissue localization of <italic>LOX3</italic> and <italic>LOX4</italic> gene expression using β‐glucuronidase (GUS) reporter gene constructs showed local induction of <italic>LOX3</italic> expression when second‐stage juveniles reached the vascular bundle and during the early stages of plant–nematode interaction through gall and syncytia formation. Thin sections of nematode‐infested knots indicated LOX3 expression in mature giant cells, and high expression in neighbouring cells and those surrounding the female body. <italic>LOX4</italic> promoter was also activated by nematode infection, although the GUS signal weakened as infection and disease progressed. Homozygous insertion mutants lacking LOX3 were less susceptible than wild‐type plants to root‐knot nematode infection, as reflected by a decrease in female counts. Conversely, deficiency in LOX4 function led to a marked increase in females and egg mass number and in the female to male ratio of <italic>M. javanica</italic> and <italic>H. schachtii</italic>, respectively. The susceptibility of <italic>lox4</italic> mutants was accompanied by increased expression of allene oxide synthase, allene oxide cyclase and ethylene‐responsive transcription factor 4, and the accumulation of jasmonic acid, measured in the roots of <italic>lox4</italic> mutants. This response was not found in <italic>lox3</italic> mutants. Taken together, our results reveal that LOX4 and LOX3 interfere differentially with distinct metabolic and signalling pathways, and that LOX4 plays a major role in controlling plant defence against nematode infection.</p> </abstract>