Deletion analysis and localization of SbPRP1, a soybean cell wall protein gene, in roots of transgenic tobacco and cowpea1

Abstract

SbPRP1 is a member of the soybean (Glycine max L. Merr) proline-rich cell wall protein family and is expressed at high levels in root tissue. To characterize the sequences required for this expression, we have fused 1.1 kb of upstream flanking DNA sequence from an SbPRP1 genomic clone to a gene encoding beta-glucuronidase (GUS). This construct was introduced into tobacco using Agrobacterium tumefaciens-mediated transformation. Histochemical staining of GUS activity in transgenic tobacco indicated that SbPRP1 is expressed in the apical and elongating region of both primary and lateral roots, most strongly in the epidermis. A similar localization pattern was found in transformed hairy roots when this construct was introduced into cowpea (Vigna aconitifolia) using Agrobacterium rhizogenes-mediated transformation. Nested 5'-deletion analysis of the SbPRP1 promoter indicated that a minimal promoter for SbPRP1 expression in roots is located within the first 262 bases of upstream flanking DNA and that the region between -1080 and -262 is required for maximal expression of this gene. Gel retardation assays showed that nuclear factors can be detected in soybean roots which specifically bind to sequences located between -1080 and -623, a region which is needed for maximal expression of the SbPRP1 promoter. Northern hybridization analysis was also used to show that little SbPRP1 mRNA was present in roots during the first 24 h after imbibition. These studies indicate that SbPRP1 expression is localized to the actively growing region of the root and that this expression is temporally regulated during very early stages of seedling growth.

Characterization and Expression of Four Proline-Rich Cell Wall Protein Genes in Arabidopsis Encoding Two Distinct Subsets of Multiple Domain Proteins

“…Screening of an Arabidopsis (Landsberg erecta) genomic library with carrot and soybean PRP probes (Chen and Varner, 1985;Suzuki et al, 1993) resulted in the identification of four distinct genomic clones encoding Pro-rich proteins (AtPRPs). cDNA clones corresponding to each of these genomic clones were isolated from a -PRL2 library (Newman et al, 1994) obtained through the Arabidopsis Biological Resource Center (Ohio State University, Columbus).…”

“…PRP gene expression is associated with early stages of legume root nodule formation (Franssen et al, 1987;van de Wiel et al, 1990;Wilson et al, 1994), soybean seedling, leaf, stem, and seed coat development (Hong et al, 1989;Kleis-San Francisco and Tierney, 1990;Lindstrom and Vodkin, 1991;Ye et al, 1991), bean seedling growth (Sheng et al, 1991), and with early stages of tomato fruit development (Santino et al, 1997). The spatial pattern of PRP expression is also tightly regulated, as shown by in situ hybridization and reporter gene expression analysis (Wyatt et al, 1992;Suzuki et al, 1993). For example, the soybean SbPRP1 and SbPRP2 transcripts have been localized to sclereids, the inner integument of the seed coat and the epidermal, cortical, and endodermoidal cells of young seedlings.…”

Expression of DcPRP1 Is Linked to Carrot Storage Root Formation and Is Induced by Wounding and Auxin Treatment

“…For example, they are expressed during the early stages of pea and soybean root nodule formation (Govers et al, 1986;Franssen et al, 1987;Van de Wiel et al, 1990) and during seedling, leaf, and seed development in soybean (Tierney et al, 1988;Hong et al, 1989;Kleis-San Francisco and Tierney, 1990;Lindstrom and Vodkin, 1991;Wyatt et al, 1992;Suzuki et al, 1993a). In many cases, expression is limited to specific cell types or organs.…”

The promoter from SlREO, a highly-expressed, root-specific Solanum lycopersicum gene, directs expression to cortex of mature roots

“…In many such biotechnology applications it will be necessary to have a promoter that is highly active in the majority of cells in mature roots of field grown crops, such that transgenes are expressed where and when they are effective. However, only a few root-specific gene promoters have been identified (Bucher, 2002) and these often have activities that are restricted to early developmental stages (Suzuki, 1993), are limited to immature central cylinder regions (Yamamoto et al 1991) or vascular tissues (Zhang et al 2003) of the root cellular structure, are heavily regulated by biotic and abiotic factors (Mudge et al 2002;Marin et al 2006;Léon-Kloosterziel et al 2005), or have been isolated because they confer rootspecificity only in seedlings where roots are growing into sucrose-rich agar media (Marin et al 2006).…”