Molecular Analysis of Brassinosteroid Action

Abstract

Brassinosteroids (BRs) are steroidal plant hormones with important regulatory roles in various physiological processes, including growth, xylem differentiation, disease resistance, and stress tolerance. Several components of the BR signal transduction pathway have been identified. The extracellular domains of receptor kinases such as BRI1 perceive BRs and transduce the signal via intracellular kinase domains. Within the cell further kinases and phosphatases determine the phosphorylation status of transcription factors such as BES1 and BZR1. These factors mediate major BR effects. Studies of BR-regulated genes shed light on the molecular mode of BR action. Genes encoding cell-wall-modifying enzymes, enzymes of the BR biosynthetic pathway, transcription factors, and proteins involved in primary and secondary metabolism are subject to BR-regulation. Gene expression data also point at interactions with other phytohormones and a role of BR in stress responses. This article gives a survey of the BR-signaling pathway. Two BR-responsive genes, OPR3 and EXO, are described in detail.

Brassinosteroid - EXO - growth - OPR3 - stress

References

• 1 Bancos S., Nomura T., Sato T., Molnar G., Bishop G. J., Koncz C., Yokota T., Nagy F., Szekeres M.. Regulation of transcript levels of the Arabidopsis cytochrome P450 genes involved in brassinosteroid biosynthesis.  Plant Physiology. (2002);  130 504-513
• 2 Bell E., Creelman R. A., Mullet J. E.. A chloroplast lipoxygenase is required for wound-induced jasmonic acid accumulation in Arabidopsis.  Proceedings of the National Academy of Sciences of the USA. (1995);  92 8675-8679
• 3 Biesgen C., Weiler E. W.. Structure and regulation of OPR1 and OPR2, two closely related genes encoding 12-oxophytodienoic acid-10,11-reductases from Arabidopsis thaliana.  Planta. (1999);  208 155-165
• 4 Bohlmann H., Vignutelli A., Hilpert B., Miersch O., Wasternack C., Apel K.. Wounding and chemicals induce expression of the Arabidopsis thaliana gene Thi2.1, encoding a fungal defense thionin, via the octadecanoid pathway.  FEBS Letters. (1998);  437 281-286
• 5 Cano-Delgado A., Yin Y., Yu C., Vafeados D., Mora-Garcia S., Cheng J.-C., Nam K.-H., Li J., Chory J.. BRL1 and BRL3 are novel brassinosteroid receptors that function in vascular differentiation in Arabidopsis.  Development. (2004);  131 5341-5351
• 6 Choe S., Dilkes B. P., Fujioka S., Takatsuto S., Sakurai A., Feldmann K. A.. The DWF4 gene of Arabidopsis encodes a cytochrome P450 that mediates multiple 22α-hydroxylation steps in brassinosteroid biosynthesis.  Plant Cell. (1998);  10 231-243
• 7 Coll-Garcia D., Mazuch J., Altmann T., Müssig C.. EXORDIUM regulates brassinosteroid-responsive genes.  FEBS Letters. (2004);  563 82-86
• 8 Cosgrove D. L.. Loosening of plant cell walls by expansins.  Nature. (2000);  407 321-326
• 9 Farrar K., Evans I. M., Topping J. F., Souter M. A., Nielsen J. E., Lindsey K.. EXORDIUM - a gene expressed in proliferating cells and with a role in meristem function, identified by promoter trapping in Arabidopsis.  The Plant Journal. (2003);  33 61-73
• 10 Friedrichsen D. M., Nemhauser J., Muramitsu T., Maloof J. N., Alonso J., Ecker J. R., Furuya M., Chory J.. Three redundant brassinosteroid early response genes encode putative bHLH transcription factors required for normal growth.  Genetics. (2002);  162 1445-1456
• 11 Goda H., Sawa S., Asami T., Fujioka S., Shimada Y., Yoshida S.. Comprehensive comparison of auxin-regulated and brassinosteroid-regulated genes in Arabidopsis.  Plant Physiology. (2004);  134 1555-1573
• 12 Goda H., Shimada Y., Asami T., Fujioka S., Yoshida S.. Microarray analysis of brassinosteroid-regulated genes in Arabidopsis.  Plant Physiology. (2002);  130 1319-1334
• 13 Hu Y., Bao F., Li J.. Promotive effect of brassinosteroids on cell division involves a distinct CycD3-induction pathway in Arabidopsis.  The Plant Journal. (2000);  24 693-701
• 14 Iba K., Gibson S., Nishiuchi T., Fuse T., Nishimura M., Arondel V., Hugly S., Somerville C.. A gene encoding a chloroplast ω‐3 fatty acid desaturase complements alterations in fatty acid desaturation and chloroplast copy number of the fad7 mutant of Arabidopsis thaliana.  The Journal of Biological Chemistry. (1993);  268 24099-24105
• 15 Kamuro Y., Takatsuto S.. Practical application of brassinosteroids in agricultural fields. Sakurai, A., Yokota, T., and Clouse, S. D., eds. Brassinosteroids. Tokyo; Springer Verlag (1999): 223-241
• 16 Kinoshita T., Cano-Delgado A., Seto H., Hiranuma S., Fujioka S., Yoshida S., Chory J.. Binding of brassinosteroids to the extracellular domain of plant receptor kinase BRI1.  Nature. (2005);  433 167-171
• 17 Krishna P.. Brassinosteroid-mediated stress responses.  Journal of Plant Growth Regulation. (2003);  22 289-297
• 18 Laudert D., Pfannschmidt U., Lottspeich F., Holländer-Czytko H., Weiler E. W.. Cloning, molecular and functional characterization of Arabidopsis thaliana allene oxide synthase (CYP74), the first enzyme of the octadecanoid pathway to jasmonates.  Plant Molecular Biology. (1996);  31 323-335
• 19 Li J.. Brassinosteroids signal through two receptor-like kinases.  Current Opinion in Plant Biology. (2003);  6 494-499
• 20 Li L., Deng X. W.. It runs in the family: regulation of brassinosteroid signaling by the BZR1-BES1 class of transcription factors.  Trends in Plant Science. (2005);  10 266-268
• 21 Lisso J., Steinhauser D., Altmann T., Kopka J., Müssig C.. Identification of brassinosteroid-related genes by means of transcript co-response analyses.  Nucleic Acids Research. (2005);  33 2685-2696
• 22 Mathur J., Molnar G., Fujioka S., Takatsuto S., Sakurai A., Yokota T., Adam G., Voigt B., Nagy F., Maas C., Schell J., Koncz C., Szekeres M.. Transcription of the Arabidopsis CPD gene, encoding a steroidogenic cytochrome P450, is negatively controlled by brassinosteroids.  The Plant Journal. (1998);  14 593-602
• 23 Müssig C., Altmann T.. Genomic brassinosteroid effects.  Journal of Plant Growth Regulation. (2003);  22 313-324
• 24 Müssig C., Biesgen C., Lisso J., Uwer U., Weiler E. W., Altmann T.. A novel stress-inducible 12-oxophytodienoate reductase from Arabidopsis thaliana provides a potential link between brassinosteroid-action and jasmonic-acid synthesis.  Journal of Plant Physiology. (2000);  157 143-152
• 25 Müssig C., Fischer S., Altmann T.. Brassinosteroid-regulated gene expression.  Plant Physiology. (2002);  129 1241-1251
• 26 Müssig C., Shin G.-H., Altmann T.. Brassinosteroids promote root growth in Arabidopsis.  Plant Physiology. (2003);  133 1261-1271
• 27 Nemhauser J. L., Chory J.. Bring it on: new insights into the mechanism of brassinosteroid action.  Journal of Experimental Botany. (2004);  55 265-270
• 28 Nemhauser J. L., Mockler T. C., Chory J.. Interdependency of brassinosteroid and auxin signaling in Arabidopsis.  PLOS Biology. (2004);  2 1460-1471
• 29 Sasse J. M.. Physiological actions of brassinosteroids: an update.  Journal of Plant Growth Regulation. (2003);  22 276-288
• 30 Schaller F., Biesgen C., Müssig C., Altmann T., Weiler E. W.. 12-oxophytodienoate reductase 3 (OPR3) is the isoenzyme involved in jasmonate biosynthesis.  Planta. (2000);  210 979-984
• 31 Schaller F., Schaller A., Stintzi A.. Biosynthesis and metabolism of jasmonates.  Journal of Plant Growth Regulation. (2004);  23 179-199
• 32 Showalter A. M.. Arabinogalactan-proteins: structure, expression and function.  Cellular and Molecular Life Sciences. (2001);  58 1399-1417
• 33 Szekeres M., Németh K., Koncz-Kálman Z., Mathur J., Kauschmann A., Altmann T., Rédei G. P., Nagy F., Schell J., Koncz C.. Brassinosteroids rescue the deficiency of CYP90, a cytochrome P450, controlling cell elongation and de-etiolation in Arabidopsis.  Cell. (1996);  85 171-182
• 34 Todd J., Post-Beittenmiller D., Jaworski J. G.. KCS1 encodes a fatty acid elongase 3-ketoacyl-CoA synthase affecting wax biosynthesis in Arabidopsis thaliana.  The Plant Journal. (1999);  17 119-130
• 35 Vert G., Nemhauser J. L., Geldner N., Hong F., Chory J.. Molecular mechanisms of steroid hormone signaling in plants.  Annual Review of Cell and Developmental Biology. (2005);  21 177-201
• 36 Wang Z.-Y., He J.-X.. Brassinosteroid signal transduction - choices of signals and receptors.  Trends in Plant Science. (2004);  9 91-96
• 37 Yin Y., Vafeados D., Tao Y., Yoshida S., Asami T., Chory J.. A new class of transcription factors mediates brassinosteroid-regulated gene expression in Arabidopsis.  Cell. (2005);  120 249-259
• 38 Yin Y., Wang Z.-Y., Mora-Garcia S., Li J., Yoshida S., Asami T., Chory J.. BES1 accumulates in the nucleus in response to brassinosteroids to regulate gene expression and promote stem elongation.  Cell. (2002);  109 181-191

Guest Editor: R. Reski