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Sugar and abscisic acid signaling orthologs are activated at the onset of ripening in grape.

Gambetta GA, Matthews MA, Shaghasi TH, McElrone AJ, Castellarin SD - Planta (2010)

Bottom Line: However, many fruits such as grape are nonclimacteric, where the onset of ripening results from the integration of multiple hormone signals including sugars and abscisic acid (ABA).Finally, exogenous sucrose and ABA regulated key orthologs in culture, similar to their regulation in the field.This study identifies novel candidates in the control of nonclimacteric fruit ripening and demonstrates that grape orthologs of key sugar and ABA-signaling components are regulated by sugar and ABA in fleshy fruit.

View Article: PubMed Central - PubMed

Affiliation: Department of Viticulture and Enology, University of California, Davis, CA 95616, USA. gagambetta@ucdavis.edu

ABSTRACT
The onset of ripening involves changes in sugar metabolism, softening, and color development. Most understanding of this process arises from work in climacteric fruits where the control of ripening is predominately by ethylene. However, many fruits such as grape are nonclimacteric, where the onset of ripening results from the integration of multiple hormone signals including sugars and abscisic acid (ABA). In this study, we identified ten orthologous gene families in Vitis vinifera containing components of sugar and ABA-signaling pathways elucidated in model systems, including PP2C protein phosphatases, and WRKY and homeobox transcription factors. Gene expression was characterized in control- and deficit-irrigated, field-grown Cabernet Sauvignon. Sixty-seven orthologous genes were identified, and 38 of these were expressed in berries. Of the genes expressed in berries, 68% were differentially expressed across development and/or in response to water deficit. Orthologs of several families were induced at the onset of ripening, and induced earlier and to higher levels in response to water deficit; patterns of expression that correlate with sugar and ABA accumulation during ripening. Similar to field-grown berries, ripening phenomena were induced in immature berries when cultured with sucrose and ABA, as evidenced by changes in color, softening, and gene expression. Finally, exogenous sucrose and ABA regulated key orthologs in culture, similar to their regulation in the field. This study identifies novel candidates in the control of nonclimacteric fruit ripening and demonstrates that grape orthologs of key sugar and ABA-signaling components are regulated by sugar and ABA in fleshy fruit.

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Related in: MedlinePlus

Vitis vinifera orthologs of the Class I HB transcription factors. a Rooted dendrogram of the entire Arabidopsis HB family with nested grape orthologs. Class I, and various subgroups are colored. b Unrooted dendrogram of the Class I HBs clustering AtHB5, AtHB6, AtHB7, AtHB12 (green dots) and other Vitis vinifera (red dots), Arabidopsis, and Populus trichocarpa orthologs. NCBI and Vitis Genoscope accessions are given
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Fig1: Vitis vinifera orthologs of the Class I HB transcription factors. a Rooted dendrogram of the entire Arabidopsis HB family with nested grape orthologs. Class I, and various subgroups are colored. b Unrooted dendrogram of the Class I HBs clustering AtHB5, AtHB6, AtHB7, AtHB12 (green dots) and other Vitis vinifera (red dots), Arabidopsis, and Populus trichocarpa orthologs. NCBI and Vitis Genoscope accessions are given

Mentions: Amino acid sequences of each ABA and sugar signaling gene of interest were obtained from NCBI. These sequences were then BLASTed against the predicted grape proteome via the Genoscope Vitis BLAST server (http://www.genoscope.cns.fr/cgi-bin/blast_server/projet_ML/blast.pl) using a BLOSUM62 matrix. In cases with reasonable numbers (<10) of predicted orthologs, all significant hits were recorded, and their corresponding genomic and predicted cDNA sequences obtained through the Genoscope Vitis genome browser (http://www.genoscope.cns.fr/externe/GenomeBrowser/Vitis/). In cases with numerous (>10) predicted orthologs, protein sequences were obtained and nested within the Arabidopsis family (CLUSTALW, BLOSUM matrix with gap open penalty of 10, gap extension penalty of 1) producing rooted dendrograms from which predicted orthologs grouping within a particular subgroup could be determined (Figs. 1, 2, 3, Suppl. Figs. 3, 4). Then genomic and predicted cDNA sequences were obtained for these predicted orthologs as above. An identical methodology was used in incorporating the P. trichocarpa orthologs and producing the unrooted dendrograms.


Sugar and abscisic acid signaling orthologs are activated at the onset of ripening in grape.

Gambetta GA, Matthews MA, Shaghasi TH, McElrone AJ, Castellarin SD - Planta (2010)

Vitis vinifera orthologs of the Class I HB transcription factors. a Rooted dendrogram of the entire Arabidopsis HB family with nested grape orthologs. Class I, and various subgroups are colored. b Unrooted dendrogram of the Class I HBs clustering AtHB5, AtHB6, AtHB7, AtHB12 (green dots) and other Vitis vinifera (red dots), Arabidopsis, and Populus trichocarpa orthologs. NCBI and Vitis Genoscope accessions are given
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2872022&req=5

Fig1: Vitis vinifera orthologs of the Class I HB transcription factors. a Rooted dendrogram of the entire Arabidopsis HB family with nested grape orthologs. Class I, and various subgroups are colored. b Unrooted dendrogram of the Class I HBs clustering AtHB5, AtHB6, AtHB7, AtHB12 (green dots) and other Vitis vinifera (red dots), Arabidopsis, and Populus trichocarpa orthologs. NCBI and Vitis Genoscope accessions are given
Mentions: Amino acid sequences of each ABA and sugar signaling gene of interest were obtained from NCBI. These sequences were then BLASTed against the predicted grape proteome via the Genoscope Vitis BLAST server (http://www.genoscope.cns.fr/cgi-bin/blast_server/projet_ML/blast.pl) using a BLOSUM62 matrix. In cases with reasonable numbers (<10) of predicted orthologs, all significant hits were recorded, and their corresponding genomic and predicted cDNA sequences obtained through the Genoscope Vitis genome browser (http://www.genoscope.cns.fr/externe/GenomeBrowser/Vitis/). In cases with numerous (>10) predicted orthologs, protein sequences were obtained and nested within the Arabidopsis family (CLUSTALW, BLOSUM matrix with gap open penalty of 10, gap extension penalty of 1) producing rooted dendrograms from which predicted orthologs grouping within a particular subgroup could be determined (Figs. 1, 2, 3, Suppl. Figs. 3, 4). Then genomic and predicted cDNA sequences were obtained for these predicted orthologs as above. An identical methodology was used in incorporating the P. trichocarpa orthologs and producing the unrooted dendrograms.

Bottom Line: However, many fruits such as grape are nonclimacteric, where the onset of ripening results from the integration of multiple hormone signals including sugars and abscisic acid (ABA).Finally, exogenous sucrose and ABA regulated key orthologs in culture, similar to their regulation in the field.This study identifies novel candidates in the control of nonclimacteric fruit ripening and demonstrates that grape orthologs of key sugar and ABA-signaling components are regulated by sugar and ABA in fleshy fruit.

View Article: PubMed Central - PubMed

Affiliation: Department of Viticulture and Enology, University of California, Davis, CA 95616, USA. gagambetta@ucdavis.edu

ABSTRACT
The onset of ripening involves changes in sugar metabolism, softening, and color development. Most understanding of this process arises from work in climacteric fruits where the control of ripening is predominately by ethylene. However, many fruits such as grape are nonclimacteric, where the onset of ripening results from the integration of multiple hormone signals including sugars and abscisic acid (ABA). In this study, we identified ten orthologous gene families in Vitis vinifera containing components of sugar and ABA-signaling pathways elucidated in model systems, including PP2C protein phosphatases, and WRKY and homeobox transcription factors. Gene expression was characterized in control- and deficit-irrigated, field-grown Cabernet Sauvignon. Sixty-seven orthologous genes were identified, and 38 of these were expressed in berries. Of the genes expressed in berries, 68% were differentially expressed across development and/or in response to water deficit. Orthologs of several families were induced at the onset of ripening, and induced earlier and to higher levels in response to water deficit; patterns of expression that correlate with sugar and ABA accumulation during ripening. Similar to field-grown berries, ripening phenomena were induced in immature berries when cultured with sucrose and ABA, as evidenced by changes in color, softening, and gene expression. Finally, exogenous sucrose and ABA regulated key orthologs in culture, similar to their regulation in the field. This study identifies novel candidates in the control of nonclimacteric fruit ripening and demonstrates that grape orthologs of key sugar and ABA-signaling components are regulated by sugar and ABA in fleshy fruit.

Show MeSH
Related in: MedlinePlus