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4719704 
Journal Article 
Tight regulation of allene oxide synthase (AOS) and allene oxide cyclase-3 (AOC3) promote Arabidopsis susceptibility to the root-knot nematode Meloidogyne javanica 
Naor, N; Gurung, FB; Ozalvo, R; Bucki, P; Sanadhya, P; Miyara, SB 
2018 
Yes 
European Journal of Plant Pathology
ISSN: 0929-1873
EISSN: 1573-8469 
Springer Netherlands 
European journal of plant pathology 
150 
1 
149-165 
English 
WOS:000419153000012 
Biosynthesis of the oxylipin jasmonic acid (JA) in Arabidopsis thaliana is catalyzed by a single allene oxide synthase (AOS)-encoding gene and four genes encoding four functional allene oxide cyclase (AOC) polypeptides (AOC1, AOC2, AOC3, and AOC4). To elucidate the biological activities of the JA pathway in regulating the plant defense response to plant-parasitic nematodes, transgenic lines carrying the GUS reporter gene under the control of individual AOC or AOS promoters were examined. Upon penetration by second-stage juveniles (J2 s), promoter activities of AOC1, AOC3 and AOC4 appeared in the root tip and root-elongation zone, with AOC3 demonstrating highest induction. At 5 days AOC3 activity continued to be highly pronounced in the stele and root cortex, associated with nematode invasion throughout gall initiation and maturation. AOS expression appeared 3 days postinfection and accompanied all later infection stages. Mutant lines were analyzed: disruption in AOS rendered plants more resistant to nematode infection, as reflected by the decreased number of females produced on this line; loss-of-function of AOC3 rendered plants more susceptible to nematode infection. Oxylipins derived from the 9- and 13-lipoxygenase pathways were assayed for their direct inhibitory activity toward M. javanica J2 s. Clear nematicidal activity of the bioactive 9- and 13-hydroperoxides was observed. Oxylipins produced by divinyl ether synthase, colneleic acid, colnelenic acid and omega 5(Z)-etherolenic acid demonstrated strong inhibitory activity. These data, along with those of other assayed oxylipins, suggest that temporal and spatial fine tuning of the JA route allowing nematodes parasitism on plant host. 
Allene oxide synthase; Allene oxide cyclase; Meloidogyne; Parasitism; Jasmonate pathway; Oxylipins