JXB Advance Access originally published online on October 10, 2006
Journal of Experimental Botany 2006 57(14):3901-3910; doi:10.1093/jxb/erl185
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© 2006 The Author(s).
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.This paper is available online free of all access charges (see http://jxb.oxfordjournals.org/open_access.html for further details)
RESEARCH PAPER |
Characterization of FaRB7, a near root-specific gene from strawberry (Fragariaxananassa Duch.) and promoter activity analysis in homologous and heterologous hosts
1Department of Tropical Plant and Soil Sciences, University of Hawaii, 3190 Maile Way, Honolulu, HI 98622, USA
2East Malling Research, New Road, East Malling, Kent ME19 6BJ, UK
3University of Durham, Department of Biological Sciences, South Road, Durham DH1 3LE, UK
4Warwick HRI, University of Warwick, Wellesbourne, Warwickshire CV35 9EF, UK
* To whom correspondence should be addressed. E-mail: andrea.massiah{at}warwick.ac.uk
Many insect and fungal pathogens posing agronomically important threats specifically target the roots in strawberry. The use of a root-specific promoter to confer expression of resistance genes in a targeted manner has the potential appreciably to benefit the genetic improvement of commercial strawberry varieties. A novel gene, FaRB7, was isolated from strawberry (Fragariaxananassa Duch.) and found to contain motifs characteristic of tonoplast intrinsic proteins (TIPs). Phylogenetic analysis revealed that FaRB7 represents an RB7-type TIP. In strawberry, this gene is expressed predominantly in roots, with very low expression in petioles. A 2.843 kb region representing the FaRB7 gene upstream regulatory sequence was isolated and found to share a number of sequence motifs with the promoter of the Nicotiana tabacum TobRB7 root-specific RB7-type TIP. When cloned upstream of the gusA reporter gene and introduced into strawberry plants, the FaRB7 promoter was shown to direct strong, near root-specific expression with expression patterns very similar to that of the endogenous gene. Furthermore, the FaRB7 promoter was found to confer constitutive expression, comparable to that produced by the cauliflower mosaic virus (CaMV) 35S RNA promoter, in tobacco. Thus, the FaRB7 promoter may be used to achieve near-root-specific transgene expression in strawberry and also represents an alternative to the CaMV 35S promoter for producing constitutive foreign gene expression in heterologous hosts. The FaRB7 full-length genomic sequence and 5' upstream regulatory region have been submitted to the EMBL/GenBank database under accession number DQ178022 [GenBank] .
Key words: Constitutive promoter, heterologous promoter, GUS, root-specific promoter, strawberry, tonoplast