title: Arabidopsis eIF5A3 influences growth and the response to osmotic and nutrient stress.
abstract: AteIF5A3, one of three genes encoding eukaryotic translation initiation factor 5A (eIF5A) in Arabidopsis thaliana, and corresponding genes PdeIF5A3 from Populus deltoides (eastern cottonwood) and SleIF5A4 from Solanum lycopersicum (tomato) were constitutively over-expressed in A. thaliana. The resultant transgenic plants exhibited enhanced vegetative and reproductive growth. Indeed, the increase in seed yield relative to empty vector controls for the PdeIF5A3 over-expressing plants ranged from 50% to 300% depending on the line. The PdeIF5A3 over-expressing plants also exhibited enhanced fitness when exposed to osmotic and nutrient (N, P and K) stress. The spatial localization of AteIF5A3 was visualized by confocal microscopy using transgenic plants expressing P(AteIF5A3) :GFP-AteIF5A3. GFP fluorescence reflecting expression of AteIF5A3 was detectable in the phloem, particularly companion cells, of roots, stems and leaves, in the epidermal cells of the root tip, in the columella cells of the root cap and in the chalazal tissue of fertilized ovules, which all play a pivotal role in nutrient or hormone translocation. Thus, AteIF5A3 appears to be involved in supporting growth and to play a regulatory role in the response of plants to sub-lethal osmotic and nutrient stress.
authors.affiliation: Department of Biology, University of Waterloo, Waterloo, Ontario, Canada.
authors.forename: Fengshan
authors.initials: F
authors.lastname: Ma
authors.forename: Zhongda
authors.initials: Z
authors.lastname: Liu
authors.forename: Tzann-Wei
authors.initials: TW
authors.lastname: Wang
authors.forename: Marianne T
authors.initials: MT
authors.lastname: Hopkins
authors.forename: Carol A
authors.initials: CA
authors.lastname: Peterson
authors.forename: John E
authors.initials: JE
authors.lastname: Thompson
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D049452:Green Fluorescent Proteins; D018551:Solanum lycopersicum / Q000235:genetics; D018977:Micronutrients; D018613:Microscopy, Confocal; D009995:Osmosis; D010448:Peptide Initiation Factors / Q000235:genetics / Q000502:physiology*; D010641:Phenotype; D030821:Plants, Genetically Modified; D032107:Populus / Q000235:genetics; D016601:RNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D013312:Stress, Physiological; D000097574:Eukaryotic Translation Initiation Factor 5A
chemical_list: D049452:Green Fluorescent Proteins; D018977:Micronutrients; D010448:Peptide Initiation Factors; D016601:RNA-Binding Proteins; D000097574:Eukaryotic Translation Initiation Factor 5A