PLANT PHYSIOLOGY , Vol 102, Issue 4 1179-1184, Copyright © 1993 by American Society of Plant Biologists

DEVELOPMENT AND GROWTH REGULATION

Selected Components of the Shade-Avoidance Syndrome Are Displayed in a Normal Manner in Mutants of Arabidopsis thaliana and Brassica rapa Deficient in Phytochrome B

PRH. Robson, G. C. Whitelam and H. Smith
Department of Botany, University of Leicester, Leicester, LE1 7RH, United Kingdom

Several growth parameters associated with the phytochrome-mediated shade avoidance syndrome have been measured in seedlings and mature plants of a wild-type and a hy3 mutant of Arabidopsis thaliana deficient in phytochrome B. Growth parameters were compared in plants grown in either white light (high red:far-red [R:FR] ratio) or white light plus added far-red (FR) light (low R:FR ratio). Wild-type Arabidopsis exhibited increased hypocotyl and petiole extension under a low, compared with a high, R:FR ratio. The hy3 mutant did not respond to low R:FR ratio by increase in hypocotyl or petiole length. Extension growth of wild-type plants was stimulated by brief end-of-day FR pulses, but similar treatment had no effect on extension growth of hy3 mutant plants. However, some responses to low R:FR ratio seen in the wild-type plants were also evident in the hy3 mutants. The number of days to bolting, the developmental stage at bolting, the leaf area, and the specific stem weight (weight per unit of length) all decreased in the wild-type and hy3 seedlings in response to low R:FR ratio. Low R:FR ratio caused a larger decrease in leaf area and specific stem weight in the mutant seedlings than in wild-type seedlings. The effects of low R:FR ratio on leaf area and specific stem weight were opposite to those of the hy3 lesion, which resulted in increased leaf area and specific stem weight in comparison with the wild type. Both leaf area and specific stem weight responses to low R:FR ratio also were unchanged in the ein mutant of Brassica rapa, known to be deficient in phytochrome B. These responses represent components of the shade-avoidance syndrome, and, consequently, the results indicate that phytochrome B cannot be solely responsible for the perception of R:FR ratio and the induction of shade-avoidance responses. The hypothesis is proposed that different phytochromes may be responsible for the regulation of extension growth and the regulation of lateral or radial expansion.

This article has been cited by other articles:

				A. C. Wollenberg, B. Strasser, P. D. Cerdan, and R. M. Amasino Acceleration of Flowering during Shade Avoidance in Arabidopsis Alters the Balance between FLOWERING LOCUS C-Mediated Repression and Photoperiodic Induction of Flowering Plant Physiology, November 1, 2008; 148(3): 1681 - 1694. [Abstract] [Full Text] [PDF]

				M. Chen and M. Ni RED AND FAR-RED INSENSITIVE 2, a RING-Domain Zinc Finger Protein, Mediates Phytochrome-Controlled Seedling Deetiolation Responses Plant Physiology, February 1, 2006; 140(2): 457 - 465. [Abstract] [Full Text] [PDF]

				K. A. FRANKLIN and G. C. WHITELAM Phytochromes and Shade-avoidance Responses in Plants Ann. Bot., August 1, 2005; 96(2): 169 - 175. [Abstract] [Full Text] [PDF]

				Y. Oka, T. Matsushita, N. Mochizuki, T. Suzuki, S. Tokutomi, and A. Nagatani Functional Analysis of a 450-Amino Acid N-Terminal Fragment of Phytochrome B in Arabidopsis PLANT CELL, August 1, 2004; 16(8): 2104 - 2116. [Abstract] [Full Text] [PDF]

				D. E. Somers, W.-Y. Kim, and R. Geng The F-Box Protein ZEITLUPE Confers Dosage-Dependent Control on the Circadian Clock, Photomorphogenesis, and Flowering Time PLANT CELL, March 1, 2004; 16(3): 769 - 782. [Abstract] [Full Text] [PDF]

				K. A. Franklin and G. C. Whitelam Light signals, phytochromes and cross-talk with other environmental cues J. Exp. Bot., January 2, 2004; 55(395): 271 - 276. [Abstract] [Full Text] [PDF]

				F. Vandenbussche, W. H. Vriezen, J. Smalle, L. J.J. Laarhoven, F. J.M. Harren, and D. Van Der Straeten Ethylene and Auxin Control the Arabidopsis Response to Decreased Light Intensity Plant Physiology, October 1, 2003; 133(2): 517 - 527. [Abstract] [Full Text] [PDF]

				K. A. Franklin, U. Praekelt, W. M. Stoddart, O. E. Billingham, K. J. Halliday, and G. C. Whitelam Phytochromes B, D, and E Act Redundantly to Control Multiple Physiological Responses in Arabidopsis Plant Physiology, March 1, 2003; 131(3): 1340 - 1346. [Abstract] [Full Text] [PDF]

				D. Staiger, L. Allenbach, N. Salathia, V. Fiechter, S. J. Davis, A. J. Millar, J. Chory, and C. Fankhauser The Arabidopsis SRR1 gene mediates phyB signaling and is required for normal circadian clock function Genes & Dev., January 15, 2003; 17(2): 256 - 268. [Abstract] [Full Text] [PDF]

				H. Tsukaya, T. Kozuka, and G.-T. Kim Genetic Control of Petiole Length in Arabidopsis thaliana Plant Cell Physiol., October 15, 2002; 43(10): 1221 - 1228. [Abstract] [Full Text] [PDF]

				S. Kircher, P. Gil, L. Kozma-Bognar, E. Fejes, V. Speth, T. Husselstein-Muller, D. Bauer, E. Adam, E. Schafer, and F. Nagy Nucleocytoplasmic Partitioning of the Plant Photoreceptors Phytochrome A, B, C, D, and E Is Regulated Differentially by Light and Exhibits a Diurnal Rhythm PLANT CELL, July 1, 2002; 14(7): 1541 - 1555. [Abstract] [Full Text] [PDF]

				M.-S. Soh, Y.-M. Kim, S.-J. Han, and P.-S. Song REP1, a Basic Helix-Loop-Helix Protein, Is Required for a Branch Pathway of Phytochrome A Signaling in Arabidopsis PLANT CELL, November 1, 2000; 12(11): 2061 - 2074. [Abstract] [Full Text]

				J. W. Reed, P. Nagpal, R. M. Bastow, K. S. Solomon, M. J. Dowson-Day, R. P. Elumalai, and A. J. Millar Independent Action of ELF3 and phyB to Control Hypocotyl Elongation and Flowering Time Plant Physiology, April 1, 2000; 122(4): 1149 - 1160. [Abstract] [Full Text]

				M. M. Neff, C. Fankhauser, and J. Chory Light: an indicator of time and place Genes & Dev., February 1, 2000; 14(3): 257 - 271. [Full Text]

				W. A. Peer, W. R. Briggs, and J. H. Langenheim Shade-avoidance responses in two common coastal redwood forest species, Sequoia sempervirens (Taxodiaceae) and Satureja douglasii (Lamiaceae), occurring in various light quality environments Am. J. Botany, May 1, 1999; 86(5): 640 - 645. [Abstract] [Full Text] [PDF]

				P. F. Devlin, P. R.H. Robson, S. R. Patel, L. Goosey, R. A. Sharrock, and G. C. Whitelam Phytochrome D Acts in the Shade-Avoidance Syndrome in Arabidopsis by Controlling Elongation Growth and Flowering Time Plant Physiology, March 1, 1999; 119(3): 909 - 916. [Abstract] [Full Text]

				M. Hanumappa, L. H. Pratt, M.-M. Cordonnier-Pratt, and G. F. Deitzer A Photoperiod-Insensitive Barley Line Contains a Light-Labile Phytochrome B Plant Physiology, March 1, 1999; 119(3): 1033 - 1040. [Abstract] [Full Text]

				P. F. Devlin, S. R. Patel, and G. C. Whitelam Phytochrome E Influences Internode Elongation and Flowering Time in Arabidopsis PLANT CELL, September 1, 1998; 10(9): 1479 - 1488. [Abstract] [Full Text]

				L. Krall and J. W. Reed The histidine kinase-related domain participates in phytochrome B function but is dispensable PNAS, July 5, 2000; 97(14): 8169 - 8174. [Abstract] [Full Text] [PDF]