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A genomics approach to understanding the role of auxin in apple (Malus x domestica) fruit size control


Devoghalaere, F and Doucen, T and Guitton, B and Keeling, J and Payne, W and Ling, TJ and Ross, JJ and Hallett, IC and Gunaseelan, K and Dayatilake, GA and Diak, R and Breen, KC and Tustin, DS and Costes, E and Chagne, D and Schaffer, RJ and David, KM, A genomics approach to understanding the role of auxin in apple (Malus x domestica) fruit size control, BMC Plant Biology, 12, (7) pp. 1-15. ISSN 1471-2229 (2012) [Refereed Article]


Copyright Statement

Licensed under Creative Commons Attribution 2.0 Generic (CC BY 2.0)

DOI: doi:10.1186/1471-2229-12-7


Background Auxin is an important phytohormone for fleshy fruit development, having been shown to be involved in the initial signal for fertilisation, fruit size through the control of cell division and cell expansion, and ripening related events. There is considerable knowledge of auxin-related genes, mostly from work in model species. With the apple genome now available, it is possible to carry out genomics studies on auxin-related genes to identify genes that may play roles in specific stages of apple fruit development. Results High amounts of auxin in the seed compared with the fruit cortex were observed in 'Royal Gala' apples, with amounts increasing through fruit development. Injection of exogenous auxin into developing apples at the start of cell expansion caused an increase in cell size. An expression analysis screen of auxin-related genes involved in auxin reception, homeostasis, and transcriptional regulation showed complex patterns of expression in each class of gene. Two mapping populations were phenotyped for fruit size over multiple seasons, and multiple quantitative trait loci (QTLs) were observed. One QTL mapped to a region containing an Auxin Response Factor (ARF106). This gene is expressed during cell division and cell expansion stages, consistent with a potential role in the control of fruit size. Conclusions The application of exogenous auxin to apples increased cell expansion, suggesting that endogenous auxin concentrations are at least one of the limiting factors controlling fruit size. The expression analysis of ARF106 linked to a strong QTL for fruit weight suggests that the auxin signal regulating fruit size could partially be modulated through the function of this gene. One class of gene (GH3) removes free auxin by conjugation to amino acids. The lower expression of these GH3 genes during rapid fruit expansion is consistent with the apple maximising auxin concentrations at this point.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Plant biology
Research Field:Plant physiology
Objective Division:Plant Production and Plant Primary Products
Objective Group:Horticultural crops
Objective Field:Horticultural crops not elsewhere classified
UTAS Author:Ling, TJ (Mr Toby Ling)
UTAS Author:Ross, JJ (Associate Professor John Ross)
ID Code:75368
Year Published:2012
Web of Science® Times Cited:122
Deposited By:Plant Science
Deposited On:2012-01-27
Last Modified:2012-08-08
Downloads:377 View Download Statistics

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