Grapes on Steroids. Brassinosteroids Are Involved in Grape Berry Ripening
Symons, GM and Davies, C and Shavrukov, Y and Dry, IB and Reid, JB and Thomas, MR (2006) Grapes on Steroids. Brassinosteroids Are Involved in Grape Berry Ripening. Plant Physiology, 140 . pp. 150-158. ISSN 0032-0889
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Official URL: http://dx.doi.org/10.1104/pp.105.070706
Fruit ripening is a unique plant developmental process with direct implications for our food supply, nutrition, and health. In contrast to climacteric fruit, where ethylene is pivotal, the hormonal control of ripening in nonclimacteric fruit, such as grape (Vitis vinifera), is poorly understood. Brassinosteroids (BRs) are steroidal hormones, essential for normal plant growth and development but not previously implicated in the ripening of nonclimacteric fruit. Here we show that increases in endogenous BR levels, but not indole-3-acetic acid (IAA) or GA levels, are associated with ripening in grapes. Putative grape homologs of genes encoding BR biosynthesis enzymes (BRASSINOSTEROID-6-OXIDASE and DWARF1) and the BR receptor (BRASSINOSTEROID INSENSITIVE 1) were isolated, and the function of the grape BRASSINOSTEROID-6-OXIDASE gene was confirmed by transgenic complementation of the tomato (Lycopersicon esculentum) extreme dwarf (dx/dx) mutant. Expression analysis of these genes during berry development revealed transcript accumulation patterns that were consistent with a dramatic increase in endogenous BR levels observed at the onset of fruit ripening. Furthermore, we show that application of
BRs to grape berries significantly promoted ripening, while brassinazole, an inhibitor of BR biosynthesis, significantly delayed
fruit ripening. These results provide evidence that changes in endogenous BR levels influence this key developmental process.
This may provide a significant insight into the mechanism controlling ripening in grapes, which has direct implications for the
logistics of grape production and down-stream processing.
|Additional Information:||Copyright © 2006 by the American Society of Plant Biologists|
|Deposited By:||Miss LJ Quittenden|
|Deposited On:||19 Aug 2011 10:19|
|Last Modified:||19 Aug 2011 10:19|
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