title: Characterization of a defensin gene expressed in oil palm inflorescences: induction during tissue culture and possible association with epigenetic somaclonal variation events.
abstract: From differential display studies performed on oil palm (Elaeis guineensis Jacq.) tissue cultures bearing or lacking an epigenetic homeotic flowering abnormality, known as mantled, EGAD1, a gene coding for a putative plant defensin, has been identified and characterized. In whole plants, transcripts of the EGAD1 gene were detected only in inflorescences. The closest characterized relative of the oil palm EGAD1 gene is the Petunia PPT gene, which is expressed principally in the pistil of the flower. The 77 amino acid polypeptide encoded by the EGAD1 gene displays strong similarities with a number of plant defensin proteins, which are thought to play a protective role and which have been shown in some cases to possess antifungal properties. Oil palm tissue cultures exhibit a generally strong induction of accumulation of EGAD1 transcripts, which were detected to differing extents at all stages of the tissue culture regeneration process. The 5' flanking region of the EGAD1 gene was found to contain two different types of potential cis-acting DNA element previously identified in the promoters of plant defence-related genes, which may explain the observed expression in tissue cultures. At the callus stage of the in vitro regeneration procedure, a differential accumulation of EGAD1 transcripts was observed which correlated with the presence or absence of the mantled flowering abnormality. EGAD1 gene expression may therefore be a marker of epigenetic somaclonal variation events.
authors.affiliation: CIRAD-CP/IRD Oil Palm Laboratory, Centre IRD Montpellier, UMR 1098, 911 avenue Agropolis, 34032 Montpellier, France. tregear@mpl.ird.fr
authors.forename: James W
authors.initials: JW
authors.lastname: Tregear
authors.forename: Fabienne
authors.initials: F
authors.lastname: Morcillo
authors.forename: Frédérique
authors.initials: F
authors.lastname: Richaud
authors.forename: Angélique
authors.initials: A
authors.lastname: Berger
authors.forename: Rajinder
authors.initials: R
authors.lastname: Singh
authors.forename: Suan Choo
authors.initials: SC
authors.lastname: Cheah
authors.forename: Caroline
authors.initials: C
authors.lastname: Hartmann
authors.forename: Alain
authors.initials: A
authors.lastname: Rival
authors.forename: Yves
authors.initials: Y
authors.lastname: Duval
mesh_terms: D024506:5' Flanking Region / Q000235:genetics; D000595:Amino Acid Sequence; D028023:Arecaceae / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular; D046508:Culture Techniques; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D023082:Defensins; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D014644:Genetic Variation; D007113:Immunity, Innate / Q000235:genetics; D008969:Molecular Sequence Data; D010935:Plant Diseases / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics*; D018514:Plant Structures / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
chemical_list: D018076:DNA, Complementary; D023082:Defensins; D010940:Plant Proteins