Natural Variation in Monoterpene Synthesis in Kiwifruit: Transcriptional Regulation of Terpene Synthases by NAC and ETHYLENE-INSENSITIVE3-Like Transcription Factors1
Fruit monoterpene synthesis in kiwifruit is transcriptionally regulated by transcription factors that activate the terpene synthase promoter. Two kiwifruit ( Actinidia ) species with contrasting terpene profiles were compared to understand the regulation of fruit monoterpene production. High rates o...
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Published in | Plant physiology (Bethesda) Vol. 167; no. 4; pp. 1243 - 1258 |
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Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
American Society of Plant Biologists
03.02.2015
|
Online Access | Get full text |
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Summary: | Fruit monoterpene synthesis in kiwifruit is transcriptionally regulated by transcription factors that activate the terpene synthase promoter.
Two kiwifruit (
Actinidia
) species with contrasting terpene profiles were compared to understand the regulation of fruit monoterpene production. High rates of terpinolene production in ripe
Actinidia arguta
fruit were correlated with increasing gene and protein expression of
A. arguta
terpene synthase1 (
AaTPS1
) and correlated with an increase in transcript levels of the 2-C-methyl-
d
-erythritol 4-phosphate pathway enzyme 1-deoxy-
d
-xylulose-5-phosphate synthase (
DXS
).
Actinidia chinensis terpene synthase1
(
AcTPS1
) was identified as part of an array of eight tandemly duplicated genes, and
AcTPS1
expression and terpene production were observed only at low levels in developing fruit. Transient overexpression of
DXS
in
Nicotiana benthamiana
leaves elevated monoterpene synthesis by AaTPS1 more than 100-fold, indicating that DXS is likely to be the key step in regulating 2-C-methyl-
d
-erythritol 4-phosphate substrate flux in kiwifruit. Comparative promoter analysis identified potential NAC (for no apical meristem [NAM], Arabidopsis transcription activation factor [ATAF], and cup-shaped cotyledon [CUC])-domain transcription factor) and ETHYLENE-INSENSITIVE3-like transcription factor (TF) binding sites in the
AaTPS1
promoter, and cloned members of both TF classes were able to activate the
AaTPS1
promoter in transient assays. Electrophoretic mobility shift assays showed that AaNAC2, AaNAC3, and AaNAC4 bind a 28-bp fragment of the proximal NAC binding site in the
AaTPS1
promoter but not the
A. chinensis AcTPS1
promoter, where the NAC binding site was mutated. Activation could be restored by reintroducing multiple repeats of the 12-bp NAC core-binding motif. The absence of NAC transcriptional activation in ripe
A. chinensis
fruit can account for the low accumulation of
AcTPS1
transcript, protein, and monoterpene volatiles in this species. These results indicate the importance of NAC TFs in controlling monoterpene production and other traits in ripening fruits. |
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Bibliography: | The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantphysiol.org) is: Niels J. Nieuwenhuizen (niels.nieuwenhuizen@plantandfood.co.nz). Present address: German Cancer Research Center, Clinical Cooperation Unit Molecular Radiooncology, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany. www.plantphysiol.org/cgi/doi/10.1104/pp.114.254367 |
ISSN: | 0032-0889 1532-2548 |
DOI: | 10.1104/pp.114.254367 |