Limits...
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.

Show MeSH

Related in: MedlinePlus

Expression of select VvHBs and VvPP2Cs in the field (left column) and in berry culture (right column). Left column field-grown berries under control (solid lines, closed circles), and deficit irrigation (dotted line, open circles). Points are colored to denote berry color. Samples collected at the onset of ripening berries were pooled according to color and points offset slightly in graph for clarity. P values are given for ANOVAs of expression with DAA (by treatment) and points at which there are significant differences between treatments are noted with an asterisk (P < 0.05; Tukey’s HSD, n = 3). Right column expression in berry culture under various treatments. Values are means with bars representing SE. Different letters denote significant differences (P < 0.05; Tukey’s HSD, n = 3)
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2872022&req=5

Fig7: Expression of select VvHBs and VvPP2Cs in the field (left column) and in berry culture (right column). Left column field-grown berries under control (solid lines, closed circles), and deficit irrigation (dotted line, open circles). Points are colored to denote berry color. Samples collected at the onset of ripening berries were pooled according to color and points offset slightly in graph for clarity. P values are given for ANOVAs of expression with DAA (by treatment) and points at which there are significant differences between treatments are noted with an asterisk (P < 0.05; Tukey’s HSD, n = 3). Right column expression in berry culture under various treatments. Values are means with bars representing SE. Different letters denote significant differences (P < 0.05; Tukey’s HSD, n = 3)

Mentions: We hypothesized that orthologs of gene families regulated by sugar and ABA, whose expression was strongly up-regulated at the onset of ripening and advanced under ED, would be regulated similarly by sugar and/or ABA in cultured berries. To test this, changes in the expression of VvHB4, VvHB8, VvPP2C-3, and VvPP2C-6 were investigated in skins of cultured berries. In the field, all genes were strongly up-regulated at the onset of ripening and advanced under ED (Fig. 7, left column) and in berry culture, expression was strongly induced in the presence of 10% sucrose + ABA when compared with treatments of 2 and 10% sucrose alone (Fig. 7, right column). Among those genes analyzed, the magnitude of induction in the field versus in berry culture was variable. For example, when data from Fig. 7 was expressed as fold change both VvHB4 and VvPP2C-3 were induced 10-fold from 57 to 74 DAA in the field compared to 6- and 40-fold in culture, respectively.Fig. 7


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)

Expression of select VvHBs and VvPP2Cs in the field (left column) and in berry culture (right column). Left column field-grown berries under control (solid lines, closed circles), and deficit irrigation (dotted line, open circles). Points are colored to denote berry color. Samples collected at the onset of ripening berries were pooled according to color and points offset slightly in graph for clarity. P values are given for ANOVAs of expression with DAA (by treatment) and points at which there are significant differences between treatments are noted with an asterisk (P < 0.05; Tukey’s HSD, n = 3). Right column expression in berry culture under various treatments. Values are means with bars representing SE. Different letters denote significant differences (P < 0.05; Tukey’s HSD, n = 3)
© Copyright Policy
Related In: Results  -  Collection

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

Fig7: Expression of select VvHBs and VvPP2Cs in the field (left column) and in berry culture (right column). Left column field-grown berries under control (solid lines, closed circles), and deficit irrigation (dotted line, open circles). Points are colored to denote berry color. Samples collected at the onset of ripening berries were pooled according to color and points offset slightly in graph for clarity. P values are given for ANOVAs of expression with DAA (by treatment) and points at which there are significant differences between treatments are noted with an asterisk (P < 0.05; Tukey’s HSD, n = 3). Right column expression in berry culture under various treatments. Values are means with bars representing SE. Different letters denote significant differences (P < 0.05; Tukey’s HSD, n = 3)
Mentions: We hypothesized that orthologs of gene families regulated by sugar and ABA, whose expression was strongly up-regulated at the onset of ripening and advanced under ED, would be regulated similarly by sugar and/or ABA in cultured berries. To test this, changes in the expression of VvHB4, VvHB8, VvPP2C-3, and VvPP2C-6 were investigated in skins of cultured berries. In the field, all genes were strongly up-regulated at the onset of ripening and advanced under ED (Fig. 7, left column) and in berry culture, expression was strongly induced in the presence of 10% sucrose + ABA when compared with treatments of 2 and 10% sucrose alone (Fig. 7, right column). Among those genes analyzed, the magnitude of induction in the field versus in berry culture was variable. For example, when data from Fig. 7 was expressed as fold change both VvHB4 and VvPP2C-3 were induced 10-fold from 57 to 74 DAA in the field compared to 6- and 40-fold in culture, respectively.Fig. 7

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