title: Isolation, expression, and characterization of a hydroperoxide lyase gene from cucumber.
abstract: A full-length cDNA coding for hydroperoxide lyase (CsHPL) was isolated from cucumber fruits of No. 26 (Southern China type) and No.14-1 (Northern China type), which differed significantly in fruit flavor. The deduced amino acid sequences of CsHPL from both lines show the same and significant similarity to known plant HPLs and contain typical conserved domains of HPLs. The recombinant CsHPL was confirmed to have 9/13-HPL enzymatic activity. Gene expression levels of CsHPL were measured in different organs, especially in fruits of different development stages of both lines. The HPL activities of fruit were identified basing on the catalytic action of crude enzyme extracts incubating with 13-HPOD (13-hydroperoxy-(9Z,12E)-octadecadienoic acid) and 13-HPOD + 9-HPOD (9-hydroperoxy-(10E,12Z)-octadecadienoic acid), and volatile reaction products were analyzed by GC-MS (gas chromatography-mass spectrometry). CsHPL gene expression in No. 26 fruit occurred earlier than that of total HPL enzyme activity and 13-HPL enzyme activity, and that in No. 14-1 fruit was consistent with total HPL enzyme activity and 9-HPL enzyme activity. 13-HPL enzyme activities decreased significantly and the 9-HPL enzyme activities increased significantly with fruit ripening in both lines, which accounted for the higher content of C6 aldehydes at 0-6 day post-anthesis (dpa) and higher content of C9 aldehydes at 9-12 dpa.
authors.affiliation: Key Laboratory of Horticultural Plant Germplasm Resources Utilization in Northwest China, College of Horticulture, Northwest A&F University, Yangling 712100, China. wanxh@nwsuaf.edu.cn.
authors.forename: Xu-Hua
authors.initials: XH
authors.lastname: Wan
authors.forename: Shu-Xia
authors.initials: SX
authors.lastname: Chen
authors.forename: Cong-Ying
authors.initials: CY
authors.lastname: Wang
authors.forename: Ran-Ran
authors.initials: RR
authors.lastname: Zhang
authors.forename: Si-Qiong
authors.initials: SQ
authors.lastname: Cheng
authors.forename: Huan-Wen
authors.initials: HW
authors.lastname: Meng
authors.forename: Xiao-Qing
authors.initials: XQ
authors.lastname: Shen
mesh_terms: D000446:Aldehyde-Lyases / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification*; D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D018553:Cucumis sativus / Q000201:enzymology*; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification*; D018076:DNA, Complementary / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D006861:Hydrogen Peroxide / Q000737:chemistry / Q000378:metabolism; D008041:Linoleic Acids / Q000737:chemistry; D008054:Lipid Peroxides / Q000737:chemistry
chemical_list: C506899:9-hydroperoxy-10,12-octadecadienoic acid; D018076:DNA, Complementary; D008041:Linoleic Acids; D008054:Lipid Peroxides; C038649:13-hydroperoxy-9,11-octadecadienoic acid; D003577:Cytochrome P-450 Enzyme System; D006861:Hydrogen Peroxide; D000446:Aldehyde-Lyases; C054540:hydroperoxide lyase