Abstract
Brassinosteroids (BRs) are essential plant hormones with roles in normal growth and development. Based on the severe light-independent hypocotyl shortening phenotype of BR mutants, it has been proposed that BRs are involved in cell elongation in darkness. To better appreciate the role of BRs in light-dependent plant development, we investigated Arabidopsis gulliver2 (gul2) mutants, which were isolated from a resistance screen against the BR biosynthetic inhibitor, brassinazole (Brz), in the presence of light. Through mapbased cloning and candidate gene sequencing, we revealed that gul2 mutants have defects in PHYTOCHROME B (PhyB). A double mutant of phyB and the BR biosynthetic mutant dwf4-1 had a dwarf phenotype that resembled that of dwf4-1, suggesting that BR biosynthesis is essential for the elongated phenotype of phyB/gul2. In addition, because preferential growth of hypocotyls in darkness is stimulated by transcription factors such as basic helix-loop-helix (bHLH) PHYTOCHROME INTERACTING FACTOR (PIF) and these proteins are more stable in darkness, we tested whether BRs affected the stability of PIFs. We found that the level of PIFs was affected neither by epi-BL nor by Brz. Therefore, we conclude that the phyB/gul2-mediated growth of hypocotyls requires the proper functioning of BR biosynthesis, and that the interplay of light and BR signaling pathways in hypocotyl growth is mediated by other mechanisms than the regulation of PIF stability.
Similar content being viewed by others
References
Bae G, Choi G (2008) Decoding of light signals by plant phytochromes and their interacting proteins. Annu Rev Plant Biol 59:281–311
Bancos S, Szatmari AM, Castle J, Kozma-Bognar L, Shibata K, Yokota T, Bishop GJ, Nagy F, Szekeres M (2006) Diurnal regulation of the brassinosteroid-biosynthetic CPD gene in Arabidopsis. Plant Physiol 141:299–309
Choe S (2004) Brassinosteroid biosynthesis and metabolism, In Davies PJ ed, Plant hormones: biosynthesis, signal transduction, action!, Kluwer Academic Publishers, Dordrecht pp 156–178
Choe S, Dilkes BP, Fujioka S, Takatsuto S, Sakurai A, Feldmann KA (1998) The DWF4 gene of Arabidopsis encodes a cytochrome P450 that mediates multiple 22a-hydroxylation steps in brassinosteroid biosynthesis. Plant Cell 10:231–243
Choe S, Dilkes BP, Gregory BD, Ross AS, Yuan H, Noguchi T, Fujioka S, Takatsuto S, Tanaka A, Yoshida S, Tax FE, Feldmann KA (1999) The Arabidopsis dwarf1 mutant is defective in the conversion of 24-methylenecholesterol to campesterol in brassinosteroid biosynthesis. Plant Physiol 119:897–907
Choe S, Fujioka S, Noguchi T, Takatsuto S, Yoshida S, Feldmann KA (2001) Overexpression of DWARF4 in the brassinosteroid biosynthetic pathway results in increased vegetative growth and seed yield in Arabidopsis. Plant J 26:573–582
Choe S, Noguchi T, Fujioka S, Takatsuto S, Tissier CP, Gregory BD, Ross AS, Tanaka A, Yoshida S, Tax FE, Feldmann KA (1999) The Arabidopsis dwf7/ste1 mutant is defective in the delta7 sterol C-5 desaturation step leading to brassinosteroid biosynthesis. Plant Cell 11:207–221
Choe S, Schmitz RJ, Fujioka S, Takatsuto S, Lee MO, Yoshida S, Feldmann KA, Tax FE (2002) Arabidopsis brassinosteroidinsensitive dwarf12 mutants are semidominant and defective in a glycogen synthase kinase 3b-like kinase. Plant Physiol 130: 1506–1515
Choe S, Tanaka A, Noguchi T, Fujioka S, Takatsuto S, Ross AS, Tax FE, Yoshida S, Feldmann KA (2000) Lesions in the sterol Δ7 reductase gene of Arabidopsis cause dwarfism due to a block in brassinosteroid biosynthesis. Plant J 21:431–443
Chung Y, Choe S (2013) The regulation of brassinosteroid biosynthesis in Arabidopsis. Crit Rev Plant Sci 32:396–410
Chung Y, Choe V, Fujioka S, Takatsuto S, Han M, Jeon JS, Park YI, Lee KO, Choe S (2012) Constitutive activation of brassinosteroid signaling in the Arabidopsis elongated-D/bak1 mutant. Plant Mol Biol 80:489–501
Chung Y, Maharjan PM, Lee O, Fujioka S, Jang S, Kim B, Takatsuto S, Tsujimoto M, Kim H, Cho S, Park T, Cho H, Hwang I, Choe S (2011) Auxin stimulates DWARF4 expression and brassinosteroid biosynthesis in Arabidopsis. Plant J 66:564–578
Clouse S (2001) Brassinosteroids. Curr Biol 11:R904
Clouse SD (1996) Molecular genetic studies confirm the role of brassinosteroids in plant growth and development. Plant J 10:1–8
Clouse SD, Langford M, McMorris TC (1996) A brassinosteroidinsensitive mutant in Arabidopsis thaliana exhibits multiple defects in growth and development. Plant Physiol 111:671–678
Filiault DL, Wessinger CA, Dinneny JR, Lutes J, Borevitz JO, Weigel D, Chory J, Maloof JN (2008) Amino acid polymorphisms in Arabidopsis phytochrome B cause differential responses to light. Proc Natl Acad Sci USA 105:3157–3162
He JX, Gendron JM, Yang Y, Li J, Wang ZY (2002) The GSK3-like kinase BIN2 phosphorylates and destabilizes BZR1, a positive regulator of the brassinosteroid signaling pathway in Arabidopsis. Proc Natl Acad Sci USA 99:10185–10190
Kang JG, Yun J, Kim DH, Chung KS, Fujioka S, Kim JI, Dae HW, Yoshida S, Takatsuto S, Song PS, Park CM (2001) Light and brassinosteroid signals are integrated via a dark-induced small G protein in etiolated seedling growth. Cell 105:625–636
Kim HB, Kwon M, Ryu H, Fujioka S, Takatsuto S, Yoshida S, An CS, Lee I, Hwang I, Choe S (2006) The regulation of DWARF4 expression is likely a critical mechanism in maintaining the homeostasis of bioactive brassinosteroids in Arabidopsis. Plant Physiol 140:548–557
Kim J, Yi H, Choi G, Shin B, Song PS, Choi G (2003) Functional characterization of phytochrome interacting factor 3 in phytochromemediated light signal transduction. Plant Cell 15:2399–2407
Kim TW, Guan S, Sun Y, Deng Z, Tang W, Shang JX, Burlingame AL, Wang ZY (2009) Brassinosteroid signal transduction from cell-surface receptor kinases to nuclear transcription factors. Nat Cell Biol 11:1254–1260
Kinoshita T, Cano-Delgado A, Seto H, Hiranuma S, Fujioka S, Yoshida S, Chory J (2005) Binding of brassinosteroids to the extracellular domain of plant receptor kinase BRI1. Nature 433:167–171
Kwon M, Fujioka S, Jeon JH, Kim HB, Takatsuto S, Yoshida S, An CS, Choe S (2005) A double mutant for the CYP85A1 and CYP85A2 genes of Arabidopsis exhibits a brassinosteroid dwarf phenotype. J Plant Biol 48:237–244
Kwon M, Lee HK, Choe S (2005) Novel Simple Sequence Length Polymorphic (SSLP) Markers for Positional Cloning in Arabidopsis thaliana. Korean J Genetics 27:1–8
Li J, Chory J (1997) A putative leucine-rich repeat receptor kinase involved in brassinosteroid signal transduction. Cell 90:929–938
Li J, Nam KH (2002) Regulation of brassinosteroid signaling by a GSK3/SHAGGY-like kinase. Science 295:1299–1301
Li J, Nam KH, Vafeados D, Chory J (2001) BIN2, a new brassinosteroid insensitive locus in Arabidopsis. Plant Physiol 127:14–22
Li J, Wen J, Lease KA, Doke JT, Tax FE, Walker JC (2002) BAK1, an Arabidopsis LRR receptor-like protein kinase, interacts with BRI1 and modulates brassinosteroid signaling. Cell 110:213–222
Maharjan PM, Schulz B, Choe S (2011) BIN2/DWF12 Antagonistically transduces brassinosteroid and auxin signals in the roots of Arabidopsis. J Plant Biol 54:126–134
Nakamura M, Satoh T, Tanaka S, Mochizuki N, Yokota T, Nagatani A (2005) Activation of the cytochrome P450 gene, CYP72C1, reduces the levels of active brassinosteroids in vivo. J Exp Bot 56:833–840
Nam KH, Li J (2002) BRI1/BAK1, a receptor kinase pair mediating brassinosteroid signaling. Cell 110:203–212
Neff M, Street I, Turk E, Ward J (2005) Interaction of light and hormone signaling to mediate photomorphogenesis, In Schäfer E, Nagy F eds, Photomorphogenesis in plants and bacteria-function and signal transduction mechanisms, Ed, Vol Springer, Dordrecht pp 441–445
Neff MM, Nguyen SM, Malancharuvil EJ, Fujioka S, Noguchi T, Seto H, Tsubuki M, Honda T, Takatsuto S, Yoshida S, Chory J (1999) BAS1: A gene regulating brassinosteroid levels and light responsiveness in Arabidopsis. Proc Natl Acad Sci USA 96:15316–15323
Noguchi T, Fujioka S, Choe S, Takatsuto S, Yoshida S, Yuan H, Feldmann KA, Tax FE (1999) Brassinosteroid-insensitive dwarf mutants of Arabidopsis accumulate brassinosteroids. Plant Physiol 121:743–752
Oh MH, Wang X, Kota U, Goshe MB, Clouse SD, Huber SC (2009) Tyrosine phosphorylation of the BRI1 receptor kinase emerges as a component of brassinosteroid signaling in Arabidopsis. Proc Natl Acad Sci USA 106:658–663
Perez-Perez JM, Ponce MR, Micol JL (2002) The UCU1 Arabidopsis gene encodes a SHAGGY/GSK3-like kinase required for cell expansion along the proximodistal axis. Dev Biol 242:161–173
Quail PH (2002) Photosensory perception and signalling in plant cells: new paradigms? Curr Opin Cell Biol 14:180–188
Schafer E, Bowle C (2002) Phytochrome-mediated photoperception and signal transduction in higher plants. EMBO Rep 3:1042–1048
Symons GM, Reid JB (2003) Hormone levels and response during de-etiolation in pea. Planta 216:422–431
Symons GM, Schultz L, Kerckhoffs LH, Davies NW, Gregory D, Reid JB (2002) Uncoupling brassinosteroid levels and deetiolation in pea. Physiol Plant 115:311–319
Symons GM, Smith JJ, Nomura T, Davies NW, Yokota T, Reid JB (2008) The hormonal regulation of de-etiolation. Planta 227:1115–1125
Takahashi N, Nakazawa M, Shibata K, Yokota T, Ishikawa A, Suzuki K, Kawashima M, Ichikawa T, Shimada H, Matsui M (2005) shk1-D, a dwarf Arabidopsis mutant caused by activation of the CYP72C1 gene, has altered brassinosteroid levels. Plant J 42:13–22
Tang W, Kim TW, Oses-Prieto JA, Sun Y, Deng Z, Zhu S, Wang R, Burlingame AL, Wang ZY (2008) BSKs mediate signal transduction from the receptor kinase BRI1 in Arabidopsis. Science 321:557–560
Turk EM, Fujioka S, Seto H, Shimada Y, Takatsuto S, Yoshida S, Denzel MA, Torres QI, Neff MM (2003) CYP72B1 inactivates brassinosteroid hormones: an intersection between photomorphogenesis and plant steroid signal transduction. Plant Physiol 133:1643–1653
Turk EM, Fujioka S, Seto H, Shimada Y, Takatsuto S, Yoshida S, Wang H, Torres QI, Ward JM, Murthy G, Zhang J, Walker JC, Neff MM (2005) BAS1 and SOB7 act redundantly to modulate Arabidopsis photomorphogenesis via unique brassinosteroid inactivation mechanisms. Plant J 42:23–34
Wang X, Chory J (2006) Brassinosteroids regulate dissociation of BKI1, a negative regulator of BRI1 signaling, from the plasma membrane. Science 313:1118–1122
Wang X, Kota U, He K, Blackburn K, Li J, Goshe MB, Huber SC, Clouse SD (2008) Sequential transphosphorylation of the BRI1/ BAK1 receptor kinase complex impacts early events in brassinosteroid signaling. Dev Cell 15:220–235
Wang ZY, Nakano T, Gendron J, He J, Chen M, Vafeados D, Yang Y, Fujioka S, Yoshida S, Asami T, Chory J (2002) Nuclearlocalized BZR1 mediates brassinosteroid-induced growth and feedback suppression of brassinosteroid biosynthesis. Dev Cell 2:505–513
Wang ZY, Seto H, Fujioka S, Yoshida S, Chory J (2001) BRI1 is a critical component of a plasma-membrane receptor for plant steroids. Nature 410:380–383
Yin Y, Vafeados D, Tao Y, Yoshida S, Asami T, Chory J (2005) A new class of transcription factors mediates brassinosteroid-regulated gene expression in Arabidopsis. Cell 120:249–259
Yin Y, Wang ZY, Mora-Garcia S, Li J, Yoshida S, Asami T, Chory J (2002) BES1 accumulates in the nucleus in response to brassinosteroids to regulate gene expression and promote stem elongation. Cell 109:181–191
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Kim, B., Kwon, M., Jeon, J. et al. The arabidopsis gulliver2/phyB mutant exhibits reduced sensitivity to brassinazole. J. Plant Biol. 57, 20–27 (2014). https://doi.org/10.1007/s12374-013-0380-3
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s12374-013-0380-3