Molecular cloning, characterization and expression analysis of CmAPX

Abstract

The RT PCR and RACE methods were used to obtain the cDNA sequence of an APX gene of muskmelon after the leaves were induced with powdery mildew. The cDNA length of the APX gene is 1,047 bp with a 750 bp ORF encoded a 249 amino acid and the molecular weight of APX protein is 27.3 kDa. The analysis showed that the CmAPX genomic DNA contained 10 extrons and 9 introns. The identity of the amino acid sequence deduced from the cDNA with the APX family of other homologous members was about 74-97%. A Full-length of ORF was sub-cloned into prokaryotic expression vector pET24a. The recombinant proteins had high expression level in E. coli. Analysis of expression at mRNA level showed that CmAPX exhibited highly tissue-specific patterns of expression. The mRNA level and enzyme activities assays showed that CmAPX might play an important role in the pathogenesis of powdery mildew.

Cloning and functional analysis of a novel ascorbate peroxidase (APX) gene from Anthurium andraeanum

“…APX activity was up-regulated substantially when plants were subjected to environmental stresses, for instance, heavy metals, high salinity, drought, high temperature, and wounding (Shi et al, 2001). APX has been cloned from many plant species such as pea (Mittler and Zilinskas, 1991), Arabidopsis (Kubo et al, 1992;Santos et al, 1996;Maruta et al, 2012), maize (van Breusegem et al, 1995), spinach (Webb and Allen, 1995;Yoshimura et al, 1999), tobacco (Orvar and Ellis, 1995), strawberry (Kim and Chung, 1998), barley (Shi et al, 2001), potato (Kawakami et al, 2002), rice (Lu et al, 2005), Vitis pseudoreticulata (Lin et al, 2006), birch (Wang et al, 2009), muskmelon (Cheng et al, 2009), lily (Chen et al, 2010), grain sorghum (Chen et al, 2011), and Nelumbo nucifera (Dong et al, 2011).…”

A Novel L-ascorbate Peroxidase 6 Gene, ScAPX6, Plays an Important Role in the Regulation of Response to Biotic and Abiotic Stresses in Sugarcane

“…Subcellular localization of ScAPX6 in rice protoplast showed that ScAPX6::GFP was targeted at chloroplast (Figure 4 ), which was consistent with the result of bioinformatics predicted localization. Similar to other plant species, such as the APXs from Cucumis melo (Cheng et al, 2009 ) and A. andraeanum (Liu et al, 2013 ), ScAPX6 also contained a plant peroxidase like superfamily and the heme binding site and shared 94.29 and 82.93% similarities with the APX homologs from S. italic APX6 (XP_004973913.1) and S. bicolor APX6 (XP_002445876.1), suggesting that ScAPX6 belongs to a member of APX family.…”

“…APX plays an important role in response to biotic and abiotic stresses (Andréia et al, 2012 ). Cheng et al ( 2009 ) observed that in C. melo , the gene expression level of CmAPX varied in different tissues, and with the highest expression in leaves and roots. Chen et al ( 2011 ) found that NuAPX showed higher expression levels in leaf stalks than in root, due to the reasons that the tissues of the leaf stalks and leaf were rich in chloroplast and mitochondria, which was the leading source of reactive oxygen species (ROS) through the electron-transport chain of photosynthesis.…”