Progress in the molecular genetic analysis of trichome initiation and morphogenesis in Arabidopsis

Szymanski, Daniel B.; Lloyd, A. C.; Marks, M. David

doi:10.1016/s1360-1385(00)01597-1

Cited by 234 publications

(215 citation statements)

References 34 publications

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“…3A). In both mutants, the staining often reached the base of cotyledons, a region where trichomes are initiated in true leaves (Lloyd et al, 1994;Szymanski et al, 2000). As reported recently for the At2S3 gene expression, the pattern and extent of staining varied between embryos from the same siliques (Kroj et al, 2003).…”

Section: Resultssupporting

confidence: 61%

AtGA3ox2, a Key Gene Responsible for Bioactive Gibberellin Biosynthesis, Is Regulated during Embryogenesis by LEAFY COTYLEDON2 and FUSCA3 in Arabidopsis

et al. 2004

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Embryonic regulators LEC2 (LEAFY COTYLEDON2) and FUS3 (FUSCA3) are involved in multiple aspects of Arabidopsis (Arabidopsis thaliana) seed development, including repression of leaf traits and premature germination and activation of seed storage protein genes. In this study, we show that gibberellin (GA) hormone biosynthesis is regulated by LEC2 and FUS3 pathways. The level of bioactive GAs is increased in immature seeds of lec2 and fus3 mutants relative to wild-type level. In addition, we show that the formation of ectopic trichome cells on lec2 and fus3 embryos is a GA-dependent process as in true leaves, suggesting that the GA pathway is misactivated in embryonic mutants. We next demonstrate that the GA-biosynthesis gene AtGA3ox2, which encodes the key enzyme AtGA3ox2 that catalyzes the conversion of inactive to bioactive GAs, is ectopically activated in embryos of the two mutants. Interestingly, both b-glucuronidase reporter gene expression and in situ hybridization indicate that FUS3 represses AtGA3ox2 expression mainly in epidermal cells of embryo axis, which is distinct from AtGA3ox2 pattern at germination. Finally, we show that the FUS3 protein physically interacts with two RY elements (CATGCATG) present in the AtGA3ox2 promoter. This work suggests that GA biosynthesis is directly controlled by embryonic regulators during Arabidopsis embryonic development.Higher plant embryogenesis is divided into two major phases: embryo development (or morphogenesis) and seed maturation (West and Harada, 1993). During embryo development, early morphogenetic processes occur that give rise to embryonic cell types, tissues, and organs. During seed maturation, the fully developed embryo undergoes maturation, during which food reserves accumulate and dormancy and desiccation tolerance develop.Seed development has been extensively studied in Arabidopsis (Arabidopsis thaliana) using mutants defective either in morphogenesis, such as GNOM (Mayer et al., 1991;Shevell et al., 1994) or KNOLLE (Mayer et al., 1991;Lukowitz et al., 1996), or in maturation, such as ABI (ABSCISIC ACID-INSENSITIVE) loci that were initially identified on the basis of the abscisic acid (ABA) hormone-resistant germination of mutants at these loci (Koornneef et al., 1984;Giraudat et al., 1992;Finkelstein et al., 1998;Finkelstein and Lynch, 2000). A particular set of mutants exhibiting the lec phenotype, which consists of a partial transformation of cotyledons into leaves, has allowed the identification of an important network of regulatory genes. The LEC1 (LEAFY COTYLEDON1; Meinke, 1992), LEC2 (Meinke et al., 1994), and FUS3 (FUSCA3;Keith et al., 1994;Meinke et al., 1994) genes, which are defined as the LEC genes hereafter, are the only known regulators required for normal development during both the morphogenesis and the maturation phases (Holdsworth et al., 1999;Harada, 2001 Article, publication date, and citation information can be found at www.plantphysiol.org/cgi

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Section: Resultssupporting

confidence: 61%

AtGA3ox2, a Key Gene Responsible for Bioactive Gibberellin Biosynthesis, Is Regulated during Embryogenesis by LEAFY COTYLEDON2 and FUSCA3 in Arabidopsis

et al. 2004

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“…The extensive studies on trichome development in Arabidopsis thaliana (e.g. Schwab et al 2000, Hu¨lskamp 2000, Szymanski et al 2000, Beilstein and Szymanski 2004 have identified a significant number of genes (e.g. ANGUSTIFOLIA, STICHEL, ZWICHEL) responsible for the genetic pathways that control trichome morphology.…”

Section: Charactersmentioning

confidence: 99%

Systematics and phylogeny of the Brassicaceae (Cruciferae): an overview

2006

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Abstract. A critical review of characters used in the systematics of the Brassicaceae is given, and aspects of the origin, classification, and generic delimitation of the family discussed. Molecular phylogenetic studies of the family were reviewed, and major clades identified. Based on molecular studies, especially from the ndhF chloroplast gene, and careful evaluation of morphology and generic circumscriptions, a new tribal alignment of the Brassicaceae is proposed. In all, 25 tribes are recognized, of which seven (Aethionemeae, Boechereae, Descurainieae, Eutremeae, Halimolobeae, Noccaeeae, and Smelowskieae) are described as new. For each tribe, the center(s) of distribution, morphology, and number of taxa are given. Of the 338 genera currently recognized in the Brassicaceae, about 260 genera (or about 77%) were either assigned or tentatively assigned to the 25 tribes. Some problems relating to various genera and tribes are discussed, and future research developments are briefly covered.

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“…A series of genes positively regulating trichome initiation and development have been identified, including TRANSPARENT TESTA GLABRA1 (TTG1) (Galway et al, 1994;Walker et al, 1999;Bouyer et al, 2008), GLABRA1 (GL1) (Oppenheimer et al, 1991), GL3, and EN-HANCER OF GLABRA3 (EGL3) (Payne et al, 2000;Szymanski et al, 2000;Zhang et al, 2003). TTG1, GL1, and GL3+EGL3 encode a WD40 protein, an R2R3 MYB transcription factor, and two basic helix-loop-helix-type transcription factors, respectively, and they form a ternary complex that initiates trichome cell development by activating GL2, which encodes a homeodomain/leucine zipper t ranscription factor (Rerie et al, 1994;Masucci et al, 1996;Schiefelbein, 2003;Pesch and Hü lskamp, 2004;Ramsay and Glover, 2005).…”

Section: Introductionmentioning

confidence: 99%

Temporal Control of Trichome Distribution by MicroRNA156-TargetedSPLGenes inArabidopsis thaliana

et al. 2010

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The production and distribution of plant trichomes is temporally and spatially regulated. After entering into the flowering stage, Arabidopsis thaliana plants have progressively reduced numbers of trichomes on the inflorescence stem, and the floral organs are nearly glabrous. We show here that SQUAMOSA PROMOTER BINDING PROTEIN LIKE (SPL) genes, which define an endogenous flowering pathway and are targeted by microRNA 156 (miR156), temporally control the trichome distribution during flowering. Plants overexpressing miR156 developed ectopic trichomes on the stem and floral organs. By contrast, plants with elevated levels of SPLs produced fewer trichomes. During plant development, the increase in SPL transcript levels is coordinated with the gradual loss of trichome cells on the stem. The MYB transcription factor genes TRICHOMELESS1 (TCL1) and TRIPTYCHON (TRY) are negative regulators of trichome development. We show that SPL9 directly activates TCL1 and TRY expression through binding to their promoters and that this activation is independent of GLABROUS1 (GL1). The phytohormones cytokinin and gibberellin were reported to induce trichome formation on the stem and inflorescence via the C2H2 transcription factors GIS, GIS2, and ZFP8, which promote GL1 expression. We show that the GIS-dependent pathway does not affect the regulation of TCL1 and TRY by miR156-targeted SPLs, represented by SPL9. These results demonstrate that the miR156-regulated SPLs establish a direct link between developmental programming and trichome distribution.

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Progress in the molecular genetic analysis of trichome initiation and morphogenesis in Arabidopsis

Cited by 234 publications

References 34 publications

AtGA3ox2, a Key Gene Responsible for Bioactive Gibberellin Biosynthesis, Is Regulated during Embryogenesis by LEAFY COTYLEDON2 and FUSCA3 in Arabidopsis

AtGA3ox2, a Key Gene Responsible for Bioactive Gibberellin Biosynthesis, Is Regulated during Embryogenesis by LEAFY COTYLEDON2 and FUSCA3 in Arabidopsis

Systematics and phylogeny of the Brassicaceae (Cruciferae): an overview

Temporal Control of Trichome Distribution by MicroRNA156-TargetedSPLGenes inArabidopsis thaliana

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