Authors: YuLing Lin ZhongXiong Lai
Publish Date: 2013/06/26
Volume: 32, Issue: 3, Pages: 595-615
Abstract
Superoxide dismutases SODs which are encoded by a multigene family are important antioxidant enzymes guarding against superoxide toxicity Because no systematic characterization of this gene family has been conducted in plant embryos the function of SODs in longan embryos is not completely clear In this study we isolated 20 fulllength cDNAs encoding cytoplasmic CSD1a and DlCSD1b chloroplastic DlCSD2a and DlFSD1a plastidic DlFSD1b and mitochondrial DlMSD from longan embryogenic callus using reverse transcriptionPCR and rapid amplification of cDNA ends Each gene possessed multiple polyadenylation sites The DlCSD1a DlCSD1b DlCSD2a DlFSD1a DlFSD1b and DlMSD genes contained eight six seven six seven and five introns respectively of greatly varying length Seven variants with different splicing modes demonstrating functional diversity during longan somatic embryogenesis SE were also cloned Each SOD gene type had multiple transcription start sites TSSs The choice of TSS affected the length of the 5′untranslated region but did not contribute to protein diversity DlCSD1a DlCSD2a DlFSD1a and DlMSD promoters were isolated and found to contain many cisacting elements responsive to stimuli such as light gibberellins auxin methyl jasmonate dehydration coldness and wounding Comprehensive expression profile analysis indicated that different SOD types exhibit different spatial and temporal expression modes and play a key role in longan SE especially during the middle and later developmental stages This study represents the first comprehensive analysis of the SOD gene family in plant SE encompassing fulllength cDNA cloning gene structures alternatively spliced variants phylogeny TSS promoter isolation and expression patterns The comparisons in this study provide insights into diverse functions of SOD isoforms during longan somatic embryo formationThis work was funded by Research Fund for the Doctoral Program of Higher Education of Chinese Ministry of Education 20093515110005 and 20123515120008 the National Natural Science Foundation of China 31078717 31272149 and 31201614 and the Fujian Provincial Natural Science Foundation of China 2012J05042
Keywords: