Functional Characterization Of GhLOX2 & GhLOX5 From Cotton In Response To Fungal Pathogens

Plant lipoxygenase are members of non heme iron containing dioxygenase family that catalyzes the oxidation of polyunsaturated fatty acids into functionally diverse oxylipins. Although the LOX (9LOX and 13LOX) has been extensively studied in plant microbe interaction both in monocot and dicot species but the role of LOX from cotton in relation to fungal pathogen remain obscure. Herein we reported the cloning and functionally characterization of two LOX genes, GhLOX2 and GhLOX5. In bioinformatics analysis, the GhLOX2 appeared to be 13LOX and whereas GhLOX5, a 9LOX. The GhLOX2 was predicted to be localized in chloroplast, whereas GhLOX5 in cytoplasm. GhLOX1 was preferentially expressed in stem, leaf and hypocotyls, whereas GhLOX5 was strongly induced in roots, flowers, ovules and hypocotyls. Induction of GhLOX2 and GhLOX5 following Verticillium dahliae inoculation, suggested their potential involvement in resistance response to fungal pathogens. GhLOX2 was strongly induced by exogenous Jasmonic acid (JA) and suppressed by Salicylic acid (SA), whereas GhLOX5 was induced by both Jasmonic acid (JA) and Salicylic acid (SA). To test the probable involvement of these genes in cotton-pathogen interaction, we employed Virus Induce Gene Silencing (VIGS) to generate GhLOX2 and GhLOX5 silenced cotton. GhLOX2 and GhLOX5-silenced cotton plants were more susceptible to Verticillium dahliae and Botrytis cinerea. Some experiments of JA/SA accumulation and expression pattern of JA/SA pathway related genes in GhLOX2 and GhLOX5-silenced cotton following inoculation of Verticillium dahliae are in process. From the given data, we suggest that GhLOX2 and GhLOX5 positively regulate the defense response to fungal pathogens.