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Uncoupling brassinosteroid levels and de-etiolation in pea


Symons, GM and Schultz, L and Kerckhoffs, LH and Davies, NW and Gregory, D and Reid, JB, Uncoupling brassinosteroid levels and de-etiolation in pea, Physiologia Plantarum, 115, (2) pp. 311-319. ISSN 0031-9317 (2002) [Refereed Article]

DOI: doi:10.1034/j.1399-3054.2002.1150219.x


The suggestion that brassinosteroids (BRs) have a negative regulatory role in de-etiolation is based largely on correlative evidence, which includes the de-etiolated phenotypes of, and increased expression of light-regulated genes in, dark-grown mutants defective in BR biosynthesis or response. However, we have obtained the first direct evidence which shows that endogenous BR levels in light-grown pea seedlings are increased, not decreased, in comparison with those grown in the dark. Similarly, we found no evidence of a decrease in castasterone (CS) levels in seedlings that were transferred from the dark to the light for 24 h. Furthermore, CS levels in the constitutively de-etiolated lip1 mutant are similar to those in wild-type plants, and are not reduced as is the case in the BR-deficient lkb plants. Unlike lip1, the pea BR-deficient mutants lk and lkb are not de-etiolated at the morphological or molecular level, as they exhibit neither a de-etiolated phenotype or altered expression of light-regulated genes when grown in the dark. Similarly, dark-grown WT plants treated with the BR biosynthesis inhibitor, Brz, do not exhibit a de-etiolated phenotype. In addition, analysis of the lip1lkb double mutant revealed an additive phenotype indicative of the two genes acting in independent pathways. Together these results strongly suggest that BR levels do not play a negative-regulatory role in de-etiolation in pea.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Plant biology
Research Field:Plant physiology
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the environmental sciences
UTAS Author:Symons, GM (Mr Gregory Symons)
UTAS Author:Schultz, L (Dr Lee Schultz)
UTAS Author:Kerckhoffs, LH (Dr Leonardus Kerckhoffs)
UTAS Author:Davies, NW (Associate Professor Noel Davies)
UTAS Author:Gregory, D (Ms Gregory)
UTAS Author:Reid, JB (Professor Jim Reid)
ID Code:25182
Year Published:2002
Web of Science® Times Cited:38
Deposited By:Plant Science
Deposited On:2002-08-01
Last Modified:2010-11-09

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