Environmental Regulation of Lateral Root Emergence in<i>Medicago truncatula</i>Requires the HD-Zip I Transcription Factor HB1

Ariel, Federico; Diet, Anouck; Verdenaud, Marion; Gruber, Véronique; Frugier, Florian; Chan, Raquel L.; Crespi, Martín

doi:10.1105/tpc.110.074823

Cited by 166 publications

(159 citation statements)

References 59 publications

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“…Previous studies have reported that HD-Zip I transcription factors are involved in abiotic stress responses (Ariel et al, 2010), fruit ripening (Lin et al, 2008), and leaf and flower senescence (Manavella et al, 2006;Lü et al, 2014). Here we showed that RhHB6 acts as a regulator of RhPR10.1, and that its expression was also up-regulated in senescent rose petals and involved in ethylene-induced flower senescence (Figs.…”

Section: Rhpr101 Inhibits Ethylene-induced Rose Flower Senescence Thsupporting

confidence: 57%

An Ethylene-Induced Regulatory Module Delays Flower Senescence by Regulating Cytokinin Content

Jia

et al. 2016

Plant Physiol.

100

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ORCID IDs: 0000-0002-6288-7917 (Y.J.); 0000-0002-5972-7963 (C.-Z.J.); 0000-0002-3866-0894 (C.M.); 0000-0002-9285-2539 (J.G.).In many plant species, including rose (Rosa hybrida), flower senescence is promoted by the gaseous hormone ethylene and inhibited by the cytokinin (CTK) class of hormones. However, the molecular mechanisms underlying these antagonistic effects are not well understood. In this study, we characterized the association between a pathogenesis-related PR-10 family gene from rose (RhPR10.1) and the hormonal regulation of flower senescence. Quantitative reverse transcription PCR analysis showed that RhPR10.1 was expressed at high levels during senescence in different floral organs, including petal, sepal, receptacle, stamen, and pistil, and that expression was induced by ethylene treatment. Silencing of RhPR10.1 expression in rose plants by virusinduced gene silencing accelerated flower senescence, which was accompanied by a higher ion leakage rate in the petals, as well as increased expression of the senescence marker gene RhSAG12. CTK content and the expression of three CTK signaling pathway genes were reduced in RhPR10.1-silenced plants, and the accelerated rate of petal senescence that was apparent in the RhPR10.1-silenced plants was restored to normal levels by CTK treatment. Finally, RhHB6, a homeodomain-Leu zipper I transcription factor, was observed to bind to the RhPR10.1 promoter, and silencing of its expression also promoted flower senescence. Our results reveal an ethylene-induced RhHB6-RhPR10.1 regulatory module that functions as a brake of ethylenepromoted senescence through increasing the CTK content.

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Section: Rhpr101 Inhibits Ethylene-induced Rose Flower Senescence Thsupporting

confidence: 57%

An Ethylene-Induced Regulatory Module Delays Flower Senescence by Regulating Cytokinin Content

Jia

et al. 2016

Plant Physiol.

100

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“…None of the Arabidopsis homologs to gt1 have been characterized genetically; however, other class I genes have been associated with functions in development (56,57) or are regulated by light (48,58). The most closely related gene that has been functionally characterized is Vrs1, which regulates the growth of lateral spikelets in barley (50).…”

Section: Discussionmentioning

confidence: 99%

grassy tillers1 promotes apical dominance in maize and responds to shade signals in the grasses

Whipple

Kebrom

Weber

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

216

218

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The shape of a plant is largely determined by regulation of lateral branching. Branching architecture can vary widely in response to both genotype and environment, suggesting regulation by a complex interaction of autonomous genetic factors and external signals. Tillers, branches initiated at the base of grass plants, are suppressed in response to shade conditions. This suppression of tiller and lateral branch growth is an important trait selected by early agriculturalists during maize domestication and crop improvement. To understand how plants integrate external environmental cues with endogenous signals to control their architecture, we have begun a functional characterization of the maize mutant grassy tillers1 (gt1). We isolated the gt1 gene using positional cloning and found that it encodes a class I homeodomain leucine zipper gene that promotes lateral bud dormancy and suppresses elongation of lateral ear branches. The gt1 expression is induced by shading and is dependent on the activity of teosinte branched1 (tb1), a major domestication locus controlling tillering and lateral branching. Interestingly, like tb1, gt1 maps to a quantitative trait locus that regulates tillering and lateral branching in maize and shows evidence of selection during maize domestication. Branching and shade avoidance are both of critical agronomic importance, but little is known about how these processes are integrated. Our results indicate that gt1 mediates the reduced branching associated with the shade avoidance response in the grasses. Furthermore, selection at the gt1 locus suggests that it was involved in improving plant architecture during the domestication of maize.

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“…The combined downregulation of GRAS genes and CYCD6 could lead to premature exit from the cell cycle in stf. Other possible targets include HOMEOBOX PROTEIN 1, which is abscisic acid responsive and a repressor of auxin-responsive lateral organ boundary domain protein in M. truncatula roots (Ariel et al, 2010), BOP1/2, LOBD38, TCP3, and KNAT2/KNAT6-related KNOX genes, which all have the potential to coordinate or interact with the auxin/cytokinin signaling machinery. However, the above three scenarios are not mutually exclusive, and it remains to be shown if they act in concert.…”

Section: Possible Mechanisms For Stf Functionmentioning

confidence: 99%

STENOFOLIARegulates Blade Outgrowth and Leaf Vascular Patterning inMedicago truncatulaandNicotiana sylvestris

et al. 2011

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Dicot leaf primordia initiate at the flanks of the shoot apical meristem and extend laterally by cell division and cell expansion to form the flat lamina, but the molecular mechanism of lamina outgrowth remains unclear. Here, we report the identification of STENOFOLIA (STF), a WUSCHEL-like homeobox transcriptional regulator, in Medicago truncatula, which is required for blade outgrowth and leaf vascular patterning. STF belongs to the MAEWEST clade and its inactivation by the transposable element of Nicotiana tabacum cell type1 (Tnt1) retrotransposon insertion leads to abortion of blade expansion in the mediolateral axis and disruption of vein patterning. We also show that the classical lam1 mutant of Nicotiana sylvestris, which is blocked in lamina formation and stem elongation, is caused by deletion of the STF ortholog. STF is expressed at the adaxial-abaxial boundary layer of leaf primordia and governs organization and outgrowth of lamina, conferring morphogenetic competence. STF does not affect formation of lateral leaflets but is critical to their ability to generate a leaf blade. Our data suggest that STF functions by modulating phytohormone homeostasis and crosstalk directly linked to sugar metabolism, highlighting the importance of coordinating metabolic and developmental signals for leaf elaboration.

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Environmental Regulation of Lateral Root Emergence inMedicago truncatulaRequires the HD-Zip I Transcription Factor HB1

Cited by 166 publications

References 59 publications

An Ethylene-Induced Regulatory Module Delays Flower Senescence by Regulating Cytokinin Content

An Ethylene-Induced Regulatory Module Delays Flower Senescence by Regulating Cytokinin Content

grassy tillers1 promotes apical dominance in maize and responds to shade signals in the grasses

STENOFOLIARegulates Blade Outgrowth and Leaf Vascular Patterning inMedicago truncatulaandNicotiana sylvestris

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