Developmental regulation and phytochrome-mediated induction of mRNAs encoding a proline-rich protein, glycine-rich proteins, and hydroxyproline-rich glycoproteins in Phaseolus vulgaris L.

Abstract

We have studied developmental and light regulation of mRNAs encoding a putative cell wall proline-rich protein (PvPRPl), cell wall glycine-rich proteins (GRPs), and cell wall hydroxyproline-rich glycoproteins (HRGPs) in bean (Phaseolus vulgaris). Light increases the levels of these mRNAs 2-to 150-fold in highly spatially regulated patterns during seedling development. These mRNA changes include differential regulation of transcripts derived from the GRP and HRGP multigene families. In 6-day-old light-grown dlings, the PvPRP1 and GRP1.0 mRNAs were most abundant in the apical region of hypocotyls, epicotyls, and roots. In contrast, several HRGP transcripts were most abundant in the mature region of hypocotyls and roots in light-grown seedlings. When etiolated 6-day-old seedings were illuminated with white light for 8 hr, maximal accumulation of PvPRP1 and GRP1.0 mRNAs occurred in the apical hook, whereas HRGP and GRP1.8 mRNAs accumulated in the mature region of hypocotyls. Etiolated seedlings subjected to a pulse ofred light accumulated PvPRP1, GRP, and HRGP mRNAs in the hypocotyls. Far-red light inhibited red light induction of these mRNAs, indicating a phytochrome-mediated process. The possible roles of PRPs, GRPs, and HRGPs in cell differentiation and photomorphogenesis are discussed.The structure and composition of plant cell walls vary depending on cell type, developmental stage, and environmental conditions. Three classes of cell wall structural proteins have been best characterized (1, 2). In dicotyledonous plants, hydroxyproline-rich glycoproteins (HRGPs), also known as extensins, contain tandem repeats of Ser-Hyp4 (3, 4). Glycine-rich proteins (GRPs) largely consist of repeating Gly-Xaa in which Xaa is frequently glycine (5, 6). Proline-rich proteins (PRPs) also possess repeating motifs and typically contain approximately equal levels of proline and hydroxyproline (7-10).All three classes of cell wall proteins and their encoding mRNAs are expressed in specific organs and cell types (11-13). For example, three transcripts of the PRP gene family in soybean (SbPRP) are differentially localized in several cell types in stems, including vascular tissues, cortical cells, and the endodermoid layer (14). In addition, differential regulation by wounding, fungal elicitor, and infection has been described for mRNAs encoding all three classes of cell wall proteins in several species (6,10,(15)(16)(17).A wealth of information exists on whole plant and cellular photomorphogenesis and the underlying physiological and biochemical changes (18, 19). Since light has a profound effect on cell expansion and differentiation, it would be expected to be a major factor regulating cell wall structural protein gene expression. However, very limited information is available on light regulation of HRGP, GRP, and PRP gene expression. Wall-bound hydroxyproline in etiolated pea seedling epicotyls increased upon red light-stimulated conversion of the phytochrome photoreceptor to its physiologically active form (20). In etiolated ...

Identification and characterization of a proline-rich mRNA that accumulates during pod development in oilseed rape (Brassica napus L.)

“…Others are produced in response to wounding [44] and light [34]. The SAC51 mRNA is present and increases in abundance when the pod has stopped growing and the protein translated from this may be involved in some other process, for example, pod dehiscence.…”

Synthetic genes for the elucidation of glycosylation codes for arabinogalactan-proteins and other hydroxyproline-rich glycoproteins

“…Specific extensins are correlated with various aspects of wall architecture such as increased tensile strength of the mechanically stressed wall [45][46][47], cessation of cell extension, cell wall rigidification [48][49][50][51], regeneration of protoplast cell walls [52], lateral root initiation [53,54], root hair growth [55,56], phyllotaxy [57], and responses to symbionts and pathogens [16,[24][25][26][27][28][29]59]. Not surprisingly, the expression of both PRPs [60][61][62][63][64][65][66][67] and extensins are under quite complex control; for example the extA gene of Brassica napus is regulated by four sets of positive and negatively acting cis regions which control wound inducibility, activation in response to tensile stress, and quantitative expression [47]. The Hyp residues in extensins (~40 mole %) occur mainly as tetra-Hyp blocks in the highly conserved [2] repetitive Ser-Hyp 4 peptide motif [7,9,68] (table 1).…”

Analysis of regulatory elements of the promoter and the 3′ untranslated region of the maize Hrgp gene coding for a cell wall protein

“…These proteins may form cross-links with other HRGP, via isodityrosine bridges, increasing the mechanical strength of cell walls (Showalter 1993;Kieliszewski and Lamport 1994). Several reports have shown that expression of HRGP genes in various species is developmentally regulated in a tissue-specific manner (Keller and Lamb 1989;Ye and Varner 1991;Sheng et al 1993) and also in response to biotic and abiotic stresses (Lawton and Lamb 1987;Showalter et al 1991;Bradley et al 1992).…”