Planta

, Volume 218, Issue 6, pp 916–927

An auxin-inducible gene from loblolly pine (Pinus taeda L.) is differentially expressed in mature and juvenile-phase shoots and encodes a putative transmembrane protein

  • Victor B. Busov
  • Eva Johannes
  • Ross W. Whetten
  • Ronald R. Sederoff
  • Steven L. Spiker
  • Carmen Lanz-Garcia
  • Barry Goldfarb
Original Article

DOI: 10.1007/s00425-003-1175-4

Cite this article as:
Busov, V.B., Johannes, E., Whetten, R.W. et al. Planta (2004) 218: 916. doi:10.1007/s00425-003-1175-4

Abstract

We have isolated a gene from loblolly pine, 5NG4, that is highly and specifically induced by auxin in juvenile loblolly pine shoots prior to adventitious root formation, but substantially down-regulated in physiologically mature shoots that are adventitious rooting incompetent. 5NG4 was highly auxin-induced in roots, stems and hypocotyls, organs that can form either lateral or adventitious roots following an auxin treatment, but was not induced to the same level in needles and cotyledons, organs that do not form roots. The deduced amino acid sequence shows homology to the MtN21 nodulin gene from Medicago truncatula. The expression pattern of 5NG4 and its homology to a protein from Medicago involved in a root-related process suggest a possible role for this gene in adventitious root formation. Homology searches also identified similar proteins in Arabidopsis thaliana and Oryza sativa. High conservation across these evolutionarily distant species suggests essential functions in plant growth and development. A 38-member family of genes homologous to 5NG4 was identified in the A. thaliana genome. The physiological significance of this redundancy is most likely associated with functional divergence and/or expression specificity of the different family members. The exact biochemical function of the gene is still unknown, but sequence and structure predictions and 5NG4::GFP fusion protein localizations indicate it is a transmembrane protein with a possible transport function.

Keywords

Adventitious root formationAuxinGene expression (5NG4)MaturationNodulinPinus

Abbreviations

ABA

Abscisic acid

BA

Benzylaminopurine

EST

Expressed sequence tag

NAA

1-Naphthaleneacetic acid

GFP

Green fluorescent protein

ORF

Open reading frame

Supplementary material

Video sequence: Cellular location of transiently expressed 5NG4:GFP4 in tobacco epidermal cells visualized with confocal laser scanning microscopy. Optical sectioning was performed in z-steps of 1 mm. Images are displayed sequentially, 10 frames per second. Scale bar: 100 mm.

video.mov (1.5 mb)
(QuickTime Movie 1.5 MB)

Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  • Victor B. Busov
    • 1
    • 2
    • 4
  • Eva Johannes
    • 3
  • Ross W. Whetten
    • 1
  • Ronald R. Sederoff
    • 1
    • 2
  • Steven L. Spiker
    • 2
  • Carmen Lanz-Garcia
    • 1
  • Barry Goldfarb
    • 1
  1. 1.Department of ForestryNorth Carolina State UniversityRaleighUSA
  2. 2.Department of GeneticsNorth Carolina State UniversityRaleighUSA
  3. 3.Department of BotanyNorth Carolina State UniversityRaleighUSA
  4. 4.Oregon State UniversityDepartment of Forest ScienceCorvallisUSA