Open AccessTwo EguCBF1 genes overexpressed in Eucalyptus display a different impact on stress tolerance and plant development
Author(s) -
Navarro Marie,
Ayax Céline,
Martinez Yves,
Laur Joan,
El Kayal Walid,
Marque Christiane,
Teulières Chantal
Publication year - 2011
Publication title -
plant biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.525
H-Index - 115
eISSN - 1467-7652
pISSN - 1467-7644
DOI - 10.1111/j.1467-7652.2010.00530.x
Subject(s) - biology , transgene , transactivation , eucalyptus , phenotype , gene , microbiology and biotechnology , arabidopsis , gene expression , botany , genetics , mutant
Summary Two C‐repeat binding factor genes (Egu CBF 1a/b), isolated from E. gunnii and differentially cold‐regulated, were constitutively overexpressed in a cold‐sensitive Eucalyptus hybrid. In addition to the expected improvement on freezing tolerance, some resulting transgenic lines (Egu CBF 1a‐OE and Egu CBF 1b‐OE) exhibited a decrease in stomata density and an over‐accumulation of anthocyanins also observed to a lesser extent in a cold‐acclimated control plant. Given that the induction of five putative CBF target genes was observed in CBF ‐overexpressing lines as well as in the cold‐acclimated control line, these phenotypes might be related to cold acclimation. In comparison with the control plant, the most altered transgenic line (Egu CBF 1a‐OE A1 line), exhibited reduced growth and better water retention capacity. This modified phenotype includes reduced leaf area and thickness associated with a decrease in cell size, as well as a higher oil gland density and a wax deposition on the cuticle. Surprisingly, the Egu CBF 1b‐OE B9 line, with a level of transgene expression equivalent to the A1 line, showed a less marked phenotype, suggesting a difference in transactivation efficiency between EguCBF1A and B factors. The features of these transgenic lines provide the first signs of adaptive mechanisms controlled by CBF transcription factors in an evergreen broad‐leaved tree. These data also open new prospects towards genetic improvement on Eucalyptus for freezing tolerance.