Cloning of the gene encoding cucumber lumazine synthase and an analysis of its promoter activity in cucumber

Abstract

M. 2010. Cloning of the gene encoding cucumber lumazine synthase and an analysis of its promoter activity in cucumber. Can. J. Plant Sci. 90: 809Á818. Promoters are an important regulatory element controlling the temporal and spatial expression of genes; thus, they play a critical role in genetic engineering by controlling target gene expression. Cucumber is a widely planted vegetable with a pleasant flavor and high economic value. However, most genetic engineering studies involving cucumber have utilized the CaMV 35S promoter, which mediates ubiquitous target gene expression. To identify a promoter that is highly expressed in cucumber fruit, total proteins from cucumber fruit were analyzed by two-dimensional gel electrophoresis. One spot which is highly expressed in fruit was sequenced from its N-terminus using the Edman degradation method. A total of 10 amino acids (Ala-Val-Arg-His-Ile-Ala-Gly-Ser-Leu-Ala) were sequenced. Based on these 10 residues, a cDNA fragment 905 bp in length was cloned using 3?-and 5?-RACE. The corresponding gene, which encodes 220 amino acids, showed 65Á73% similarity to other plant lumazine synthases without the signal peptide. We also cloned the 2.1-kb upstream promoter sequence of this Cucumis sativus lumazine synthase (CsLS) and analyzed its promoter activity by GUS histochemical and fluorometric assays. Our results indicate that CsLS is highly expressed in cucumber fruit, whereas it is expressed at low levels in cucumber stems and leaves.Key words: Cucumber, promoter, 2-DE, RACE, lumazine synthase Wang, R., Chen, M., Liao, F., Jiang, F., Ma, B., Zhang, Y. et Li, M. 2010. Clonage du ge`ne codant la lumazine synthase et analyse de ses effets sur la croissance du concombre. Can. J. Plant Sci. 90: 809Á818. Les facteurs de croissance jouent un important roˆle de re´gulation, car ils controˆlent l'expression des ge`nes dans le temps et l'espace. Par conse´quent, leur activiteé st de´terminante en ge´nie ge´ne´tique, car ils re´gissent l'expression des ge`nes cible´s. Le concombre est un le´gume abondamment cultive´au gouˆt agre´able et d'une grande valeur e´conomique. Pourtant, la majeure partie des recherches en ge´nie ge´ne´tique sur cette plante recourent au facteur de croissance CaMV 35S, qui influe sur l'expression de nombreux ge`nes. Pour identifier un facteur de croissance s'exprimant vigoureusement chez le concombre, les auteurs ont analyseĺ 'ensemble des prote´ines du le´gume par e´lectrophore`se bidimensionnelle. Une tache s'exprimant vivement chez le fruit a e´teś e´quence´e a`partir du re´sidu amine´terminal selon la me´thode d'Edman. En tout, dix acides amine´s (Ala-Val-Arg-His-IleAla-Gly-Ser-Leu-Ala) ont ainsi e´te´se´quence´s. À partir de ces dix re´sidus, les auteurs ont clone´un fragment d'ADNc de 905 bp aux extre´mite´s 3? et 5? (RACE). Le ge`ne correspondant, qui code 220 acides amine´s, pre´sente une similitude de 65 a7 3 % avec d'autres lumazine synthases ve´ge´tales, en plus de la se´quence-signal. Les auteurs ont e´galement clone´la se´quence du facteur de croiss...

Stability determination of candidate reference genes in cucumber plants subjected to stresses from Phytophthora melonis

“…Cucumber, which is one of the most important members of the Cucurbitaceae family, is widely cultivated worldwide. Studies on cucumber molecular biology has made signi icant progress [19][20][21][22][23], after cucumber genome sequencing data were released [24]. Cucumber blight caused by Phytophthora.…”