Creating a two-dimensional pattern de novo during Arabidopsis trichome and root hair initiation

Pesch, Martina; Hülskamp, Martin

doi:10.1016/j.gde.2004.06.007

Cited by 128 publications

(149 citation statements)

References 39 publications

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“…Efforts to mathematically model the root epidermis patterning system have assumed such an autoregulatory feedback loop, even though this has not, until recently, been experimentally identified (Pesch and Hulskamp, 2004;Benitez et al, 2007). In these mathematical models, WER has been hypothesized to promote its own expression to provide the autoregulatory feedback.…”

Section: Discussion a Myb23 Positive Feedback Loop Enhances Wer-direcmentioning

confidence: 99%

TheMYB23Gene Provides a Positive Feedback Loop for Cell Fate Specification in theArabidopsisRoot Epidermis

et al. 2009

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The specification of cell fates during development requires precise regulatory mechanisms to ensure robust cell type patterns. Theoretical models of pattern formation suggest that a combination of negative and positive feedback mechanisms are necessary for efficient specification of distinct fates in a field of differentiating cells. Here, we examine the role of the R2R3-MYB transcription factor gene, AtMYB23 (MYB23), in the establishment of the root epidermal cell type pattern in Arabidopsis thaliana. MYB23 is closely related to, and is positively regulated by, the WEREWOLF (WER) MYB gene during root epidermis development. Furthermore, MYB23 is able to substitute for the function of WER and to induce its own expression when controlled by WER regulatory sequences. We also show that the MYB23 protein binds to its own promoter, suggesting a MYB23 positive feedback loop. The localization of MYB23 transcripts and MYB23-green fluorescent protein (GFP) fusion protein, as well as the effect of a chimeric MYB23-SRDX repressor construct, links MYB23 function to the developing non-hair cell type. Using mutational analyses, we find that MYB23 is necessary for precise establishment of the root epidermal pattern, particularly under conditions that compromise the cell specification process. These results suggest that MYB23 participates in a positive feedback loop to reinforce cell fate decisions and ensure robust establishment of the cell type pattern in the Arabidopsis root epidermis.

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Section: Discussion a Myb23 Positive Feedback Loop Enhances Wer-direcmentioning

confidence: 99%

TheMYB23Gene Provides a Positive Feedback Loop for Cell Fate Specification in theArabidopsisRoot Epidermis

et al. 2009

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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). Another group of genes encode the single-repeat R3 MYB factors TRIPTYCHON (TRY), CAPRICE (CPC), ENHANCER OF TRY AND CPC1 (ETC1), ETC2, ETC3, and TRICHOMELESS1 (TCL1) (Wada et al, 1997;Esch et al, 2004;Kirik et al, 2004aKirik et al, , 2004bSchellmann et al, 2002;Simon et al, 2007;Wang et al, 2007).…”

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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“…The Myb-bHLH-WD40 complex activates the expression of multiple downstream factors, each of which directs the morphogenesis or lateral inhibition of the developing trichomes (Szymanski et al, 1998;Schellmann et al, 2002;Ishida et al, 2007;Zhao et al, 2008). Thus, the current model of trichome patterning comprises a local autonomous circuit of multiple transcription factors acting at leaf primordia (Pesch and Hülskamp, 2004;Bouyer et al, 2008). However, herbivore-induced damage at older leaves does affect newly forming leaves and changes the frequency at which epidermal cells adopt the trichome fate, implying that a mobile signal must exist to control trichome fate specification in a systemic manner.…”

Section: Introductionmentioning

confidence: 99%

Jasmonic acid control of GLABRA3 links inducible defense and trichome patterning inArabidopsis

et al. 2009

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Once attacked by herbivores, plants regenerate new leaves with increased trichome density as an inducible defense. Trichomes are specified from neighboring epidermal cells through local cell-cell interactions in the leaf primordia. However, the molecular mechanism of how herbivore-induced damage at older leaves remodels the pattern of trichome fate specification at newly forming leaves is largely unknown. In this study, we show that mutations in either the biosynthetic or signaling pathway of jasmonates (JAs), long-distance wound signals, abolish the wound-induced formation of trichomes. To identify the factors linking JA signaling to trichome fate specification, we isolated a novel class of mutants, unarmed (urm), which lack trichome induction but show otherwise normal responses to JAs. URM9 encodes an Importin β family protein, and URM23 is identical to TRANSPARENT TESTA GLABRA1 (TTG1), the product of which interacts with the bHLH transcription factor GLABRA3 (GL3). Loss of either URM9 or URM23 disrupts the subnuclear localization of GL3, thus implicating GL3 in trichome induction. The expression of GL3 was enhanced by JA treatment prior to trichome initiation. Genetic analysis of multiple trichome mutants shows that GL3, in concert with the R2R3-Myb transcription factor GLABRA1 (GL1), promotes trichome fate in response to JA in a dosage-dependent manner. These results indicate that GL3 is a key transcription factor of wound-induced trichome formation acting downstream of JA signaling in Arabidopsis.

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Creating a two-dimensional pattern de novo during Arabidopsis trichome and root hair initiation

Cited by 128 publications

References 39 publications

TheMYB23Gene Provides a Positive Feedback Loop for Cell Fate Specification in theArabidopsisRoot Epidermis

TheMYB23Gene Provides a Positive Feedback Loop for Cell Fate Specification in theArabidopsisRoot Epidermis

Temporal Control of Trichome Distribution by MicroRNA156-TargetedSPLGenes inArabidopsis thaliana

Jasmonic acid control of GLABRA3 links inducible defense and trichome patterning inArabidopsis

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