Molecular cloning and characterization of a lipoxygenase gene (CsLOX1) from cucumber

Abstract

Lipoxygenases (LOXs) are non-heme iron enzymes that play crucial roles in many developmental processes during plant life, and defense responses against biotic and abiotic stresses. In this study, a lipoxygenase gene (CsLOX1) was cloned and characterized from cucumber (Cucumis sativus). The coding sequence (CDS) of CsLOX1 was 741 bp, and encoded an 878 amino-acid residue protein, which was predicted to be located in the cytoplasm. CsLOX1 contained the conserved LH2/PLAT and lipoxygenase domains, as well as the representative 38 amino acids motif [His-(X)4-His-(X)4-His-(X)17-His-(X)8-His]. Multiple sequence alignment and phylogenetic analysis indicated that CsLOX1 was closely related to other dicot 9-LOXs and posesess the essential conserved residues involved in the binding of the iron atom. Promoter analysis suggested that several development-, stress-, and hormone-related cis-acting regulatory elements were present in the promoter region of CsLOX1. The function of CsLOX1 was assessed by overexpression it in Arabidopsis, and the transgenic plants were male sterile and displayed obviously increased floral shoots. These results provide some clues for revealing the biological roles of CsLOX1 in cucumber.