The Role of Brassinosteroids in Shoot Gravitropism

Vandenbussche, Filip; Suslov, Dmitry; Grauwe, Luc De; Leroux, Olivier; Vissenberg, Kris; Straeten, Dominique Van Der

doi:10.1104/pp.111.177873

Cited by 35 publications

(56 citation statements)

References 24 publications

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“…The sugar hypersensitivity of brassinosteroid, light, sugar mutant, is rescued on exogenous BR application (Laxmi et al, 2004). Recently, Vandenbussche and coworkers showed that an exogenous application of BR causes agravitropism in dark-grown Arabidopsis hypocotyls while sugar can antagonize this BR-inhibited gravitropism (Vandenbussche et al, 2011) that we extend here to mechanism. This BR reset of hypocotyl gravitropism response involves the BR receptor and signaling elements ( Fig.…”

Section: Discussionmentioning

confidence: 72%

“…Changes in auxin, ethylene, gravity signaling, or alteration in cell wall properties alter hypocotyl growth direction (De Grauwe et al, 2005;Vandenbussche et al, 2011). The cytoskeleton also plays a crucial role in optimal hypocotyl direction as evident by the hypocotyl phenotypes of seedlings harboring mutations in genes encoding various microtubule-interacting proteins (Blancaflor, 2002;Bisgrove, 2008).…”

Section: The Relevance Of Br For Optimal Hypocotyl Growth Directionmentioning

confidence: 99%

“…X-Gluc was prepared as 100 mg L 21 stock solution in N,Ndimethylformamide. All treatment concentrations for this study were chosen from previously published reports (Nakamura et al, 2004b;Deslauriers and Larsen, 2010;Kim et al, 2011;Kushwah et al, 2011;Vandenbussche et al, 2011).…”

Section: Plant Materials and Growth Conditionsmentioning

confidence: 99%

“…BR acts synergistically with auxin during hypocotyl gravitropism of partially deetiolated bean (Phaseolus vulgaris; Meudt, 1987). Finally, BRs inhibit gravitropic responses of etiolated Arabidopsis (Arabidopsis thaliana) hypocotyls (Nakamoto et al, 2006) and sugar antagonizes this BR inhibition (Vandenbussche et al, 2011). Modified starch accumulation, loss of cell wall rigidity, and a faulty osmoregulation may be responsible for BR-induced loss of hypocotyl graviresponses.…”

mentioning

confidence: 99%

“…Collectively, these reports that individually reveal a role of different hormones or sugars in controlling Arabidopsis hypocotyl directional responses imply integration among these different signals. Here, we provide a mechanism for this signal integration and speculate on the biological significance (Vandenbussche et al, 2011).…”

mentioning

confidence: 99%

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Hypocotyl Directional Growth in Arabidopsis: A Complex Trait

et al. 2012

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The growth direction of the Arabidopsis (Arabidopsis thaliana) etiolated-seedling hypocotyl is a complex trait that is controlled by extrinsic signals such as gravity and touch as well as intrinsic signals such as hormones (brassinosteroid [BR], auxin, cytokinin, ethylene) and nutrient status (glucose [Glc], sucrose). We used a genetic approach to identify the signaling elements and their relationship underlying hypocotyl growth direction. BR randomizes etiolated-seedling growth by inhibiting negative gravitropism of the hypocotyls via modulating auxin homeostasis for which we designate as reset, not to be confused with the gravity set point angle. Cytokinin signaling antagonizes this BR reset of gravity sensing and/or tropism by affecting ethylene biosynthesis/signaling. Glc also antagonizes BR reset but acts independently of cytokinin and ethylene signaling pathways via inhibiting BR-regulated gene expression quantitatively and spatially, by altering protein degradation, and by antagonizing BR-induced changes in microtubule organization and cell patterning associated with hypocotyl agravitropism. This BR reset is reduced in the presence of the microtubule organization inhibitor oryzalin, suggesting a central role for cytoskeleton reorganization. A unifying and hierarchical model of Glc and hormone signaling interplay is proposed. The biological significance of BR-mediated changes in hypocotyl graviresponse lies in the fact that BR signaling sensitizes the dark-grown seedling hypocotyl to the presence of obstacles, overriding gravitropism, to enable efficient circumnavigation through soil.

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Section: Discussionmentioning

confidence: 72%