Modulation of eIF5A1 expression alters xylem abundance in Arabidopsis thaliana

• Published in: Journal of experimental botany Vol. 59; no. 4; pp. 939 - 950
• Main Authors: Liu, Zhongda, Duguay, Jeremy, Ma, Fengshan, Wang, Tzann-Wei, Tshin, Ruth, Hopkins, Marianne T., McNamara, Linda, Thompson, John E.
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.03.2008; Oxford Publishing Limited (England)
• Subjects: Amino Acid Sequence; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis Proteins - chemistry; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Arabidopsis thaliana; Auxins; Developmental biology; Down-Regulation; Eukaryotic Translation Initiation Factor 5A; Gene Expression Regulation, Plant - physiology; inflorescence stem; Inflorescences; Molecular Sequence Data; Peptide Initiation Factors - chemistry; Peptide Initiation Factors - genetics; Peptide Initiation Factors - metabolism; Plant Stems - cytology; Plant Stems - metabolism; Plants; Plants, Genetically Modified; Proteins; RESEARCH PAPER; RNA-Binding Proteins - chemistry; RNA-Binding Proteins - genetics; RNA-Binding Proteins - metabolism; Secondary xylem; Stems; Transgenic plants; Up-Regulation; Xylem; Xylem - metabolism; Xylem vessels; xylem; inflorescence stem; eukaryotic translation initiation factor 5A
• ISSN: 0022-0957; 1460-2431
• DOI: 10.1093/jxb/ern017

Eukaryotic translation initiation factor 5A (eIF5A) is thought to facilitate protein synthesis by participating in the nuclear export of specific mRNAs. In Arabidopsis, there are three isoforms of eIF5A. One of them, AteIF5A1, has been shown to be expressed in vascular tissue, specifically developing vessel members, using GUS as a reporter. In order to determine whether AteIF5A1 plays a role in xylem formation, its full-length cDNA was constitutively over-expressed in transgenic Arabidopsis plants. Microscopic analysis revealed that the cross-sectional area of the xylem in the main inflorescence stems of transgenic plants was 1.9-fold higher than those of corresponding inflorescence stems of wild-type plants. In wild-type stems, the primary xylem typically comprised six cell layers and was ∼105 μm thick, but increased to 9–11 cell layers, 140–155 μm thick, in transgenic stems. Similarly, the secondary xylem increased from six cell layers, ∼70 μm thick, in control stems to ∼9 cell layers, 95–105 μm thick, in transgenic stems. Moreover, constitutive down-regulation of AteIF5A1 using antisense technology resulted in the major suppression of xylem formation compared with control plants, and the antisense transgenic plants were also stunted. These data collectively indicate that eIF5A1 plays a role in xylogenesis.