Ectopic expression of a novel MYB gene modifies the architecture of the Arabidopsis inflorescence

Abstract

SummaryThe Arabidopsis thaliana mutants fus3, lec1 and abi3 have pleiotropic defects during late embryogenesis. Mutant embryos fail to enter the maturation programme and initiate a vegetative germination pathway instead. Screening for genes which are differentially expressed in the fus3 mutant of Arabidopsis resulted in the isolation of several members of the MYB family. MYB domain proteins in plants represent an extended gene family of transcription factors, suggesting their participation in a variety of plant specific cellular functions. Here, the authors describe one of these genes, designated AtMYB13, representing a novel member of the MYB gene family. The structure of the gene as well as its genomic organisation and localisation are reported. The expression of the gene is regulated by dehydration, exogenous abscisic acid, light and wounding. A chimeric AtMYB13 promoter/GUS gene is tissuespecifically expressed in transgenic Arabidopsis plants. The GUS staining was predominantly detected in the shoot apex zone and at the basis of developing flowers. In addition, the AtMYB13 gene promoter is active at branching points of the inflorescence. Furthermore, ectopic expression of the AtMYB13 gene has a characteristic impact on the architecture of the inflorescence leading to peculiar hook structures at pedicel branching points. In addition, some transgenic plants exhibit a reversed order of first flowers and axillary buds. These data suggest a function of the AtMYB13 gene product in linking shoot morphogenic activity with environmental as well as intrinsic signals.

Isolation and characterization ofMyb-related genes from oil palm (Elaeis guineensis Jacq.)

“…Overexpression in transgenic tobacco plants also induces the expression of a tobacco retrotransposon, -/-to7, as well as a PAL gene. Ectopic overexpression of AtMYB13 can lead to a change in florescence architecture (Kirik et al, 1998). Although in the current study, OpMyb24 responded to injury, no specific data delineates its exact role in wound signaling.…”

A GlutathioneS-Transferase Regulated by Light and Hormones Participates in the Modulation of Arabidopsis Seedling Development

“…In addition, the atgstu17 mutant in the presence of ABA showed down-regulated levels of 12 MYB genes (Supplemental Table S2), which mainly participate in the regulation of the architecture of Arabidopsis inflorescence (Kirik et al, 1998), floral development (Baumann et al, 2007;Zhou et al, 2008;Zhang et al, 2009), phosphate starvation response (Devaiah et al, 2009), epidermal cell outgrowth (Jakoby et al, 2008), cell wall biosynthesis (Zhong et al, 2008), ABA signaling, and drought stress (Urao et al, 1996; Abe et al, 2003). In conclusion, AtGSTU17 regulated by various photoreceptors, especially phyA, and different phytohormones, including auxin and ABA, may have complicated functions regulating gene expression and plant development such as hypocotyl and root elongation, as well as stress responses by fine tuning GSH homeostasis and redox status in response to changes in light and environmental signals (Fig.…”

The MYB Transcription Factor Superfamily of Arabidopsis: Expression Analysis and Phylogenetic Comparison with the Rice MYB Family

“…They were reported to be involved in many physiological and biochemical processes, such as the regulation of secondary metabolism (Paz-Ares et al, 1987;Grotewold et al, 1994;Bender and Fink, 1998;Hoeren et al, 1998;Mol et al, 1998, Tamagnone et al, 1998Borevitz et al, 2000;Jin et al, 2000;Nesi et al, 2001;Baudry et al, 2004), the control of cell morphogenesis (Oppenheimer et al, 1991, Noda et al, 1994Glover et al, 1998;Payne et al, 1999;Schiefelbein, 1999, 2001;Higginson et al, 2003), the regulation of meristem formation and floral and seed development (Kirik et al, 1998b;Li et a1.,1999;Timmermans et al, 1999;Penfield et al, 2001;Schmitz et al,, 2002;Shin et al, 2002;Steiner-Lange, 2003), and the control of cell cycle (Ito et al, 2001;Araki et al, 2004). Some were also involved in various defense and stress responses (Urao et a1., 1993;Daniel et al, 1999;Sugimoto et al, 2000;Hemm et al, 2001;Stockinger et al, 2001;Vailleau et al, 2002;Abe et al, 2003;Denekamp and Smeekens, 2003;Nagaoka and Takano, 2003) and in light and hormone signaling pathways (Gubler et al, 1995;Iturriaga et al, 1996;Wang et al...…”