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Co-ordination of early and late ripening events in apples is regulated through differential sensitivities to ethylene.

Johnston JW, Gunaseelan K, Pidakala P, Wang M, Schaffer RJ - J. Exp. Bot. (2009)

Bottom Line: In this study, it is shown that anti-sense suppression of Malus domestica 1-AMINO-CYCLOPROPANE-CARBOXYLASE OXIDASE (MdACO1) resulted in fruit with an ethylene production sufficiently low to be able to assess ripening in the absence of ethylene.A sustained exposure to ethylene was required to maintain ripening, indicating that the role of ethylene may go beyond that of ripening initiation.These results suggest a conceptual model for the control of individual ripening characters in apple, based on both ethylene dependency and sensitivity.

View Article: PubMed Central - PubMed

Affiliation: The New Zealand Institute For Plant & Food Research Limited, Private Bag 92169, Auckland, New Zealand.

ABSTRACT
In this study, it is shown that anti-sense suppression of Malus domestica 1-AMINO-CYCLOPROPANE-CARBOXYLASE OXIDASE (MdACO1) resulted in fruit with an ethylene production sufficiently low to be able to assess ripening in the absence of ethylene. Exposure of these fruit to different concentrations of exogenous ethylene showed that flesh softening, volatile biosynthesis, and starch degradation, had differing ethylene sensitivity and dependency. Early ripening events such as the conversion of starch to sugars showed a low dependency for ethylene, but a high sensitivity to low concentrations of ethylene (0.01 microl l(-1)). By contrast, later ripening events such as flesh softening and ester volatile production showed a high dependency for ethylene but were less sensitive to low concentrations (needing 0.1 microl l(-1) for a response). A sustained exposure to ethylene was required to maintain ripening, indicating that the role of ethylene may go beyond that of ripening initiation. These results suggest a conceptual model for the control of individual ripening characters in apple, based on both ethylene dependency and sensitivity.

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Related in: MedlinePlus

Untransformed ‘Royal Gala’ (RG, wild type) and MdACC oxidase1 (ACO1as) fruit at harvest. Concentration of internal ethylene in the core cavity (A), background skin colour (B), starch pattern index (C), soluble solids concentration (D), flesh firmness (E), and titratable acidity (F).
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fig1: Untransformed ‘Royal Gala’ (RG, wild type) and MdACC oxidase1 (ACO1as) fruit at harvest. Concentration of internal ethylene in the core cavity (A), background skin colour (B), starch pattern index (C), soluble solids concentration (D), flesh firmness (E), and titratable acidity (F).

Mentions: At harvest, the control fruit had internal ethylene concentrations ranging from 0.05 to 528 μl l−1, while the MdACO1as fruit had levels ranging from undetectable to 0.08 μl l−1 (Fig. 1A). Both the control fruit and MdACO1as fruit on exposed parts of the trees developed red blush at harvest (Fig. 2A, B), although the intensity and skin coverage of reddening was more pronounced on control fruit. Both fruit types had similar flesh firmness, but the MdACO1as fruit had lower concentrations of soluble solids and titratable acidity, less starch clearance, and a greener background skin colour (Fig. 1B–E). The starch pattern index for control fruit ranged from 0 to 6 and 0 to 3 in MdACO1as fruit.


Co-ordination of early and late ripening events in apples is regulated through differential sensitivities to ethylene.

Johnston JW, Gunaseelan K, Pidakala P, Wang M, Schaffer RJ - J. Exp. Bot. (2009)

Untransformed ‘Royal Gala’ (RG, wild type) and MdACC oxidase1 (ACO1as) fruit at harvest. Concentration of internal ethylene in the core cavity (A), background skin colour (B), starch pattern index (C), soluble solids concentration (D), flesh firmness (E), and titratable acidity (F).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2692014&req=5

fig1: Untransformed ‘Royal Gala’ (RG, wild type) and MdACC oxidase1 (ACO1as) fruit at harvest. Concentration of internal ethylene in the core cavity (A), background skin colour (B), starch pattern index (C), soluble solids concentration (D), flesh firmness (E), and titratable acidity (F).
Mentions: At harvest, the control fruit had internal ethylene concentrations ranging from 0.05 to 528 μl l−1, while the MdACO1as fruit had levels ranging from undetectable to 0.08 μl l−1 (Fig. 1A). Both the control fruit and MdACO1as fruit on exposed parts of the trees developed red blush at harvest (Fig. 2A, B), although the intensity and skin coverage of reddening was more pronounced on control fruit. Both fruit types had similar flesh firmness, but the MdACO1as fruit had lower concentrations of soluble solids and titratable acidity, less starch clearance, and a greener background skin colour (Fig. 1B–E). The starch pattern index for control fruit ranged from 0 to 6 and 0 to 3 in MdACO1as fruit.

Bottom Line: In this study, it is shown that anti-sense suppression of Malus domestica 1-AMINO-CYCLOPROPANE-CARBOXYLASE OXIDASE (MdACO1) resulted in fruit with an ethylene production sufficiently low to be able to assess ripening in the absence of ethylene.A sustained exposure to ethylene was required to maintain ripening, indicating that the role of ethylene may go beyond that of ripening initiation.These results suggest a conceptual model for the control of individual ripening characters in apple, based on both ethylene dependency and sensitivity.

View Article: PubMed Central - PubMed

Affiliation: The New Zealand Institute For Plant & Food Research Limited, Private Bag 92169, Auckland, New Zealand.

ABSTRACT
In this study, it is shown that anti-sense suppression of Malus domestica 1-AMINO-CYCLOPROPANE-CARBOXYLASE OXIDASE (MdACO1) resulted in fruit with an ethylene production sufficiently low to be able to assess ripening in the absence of ethylene. Exposure of these fruit to different concentrations of exogenous ethylene showed that flesh softening, volatile biosynthesis, and starch degradation, had differing ethylene sensitivity and dependency. Early ripening events such as the conversion of starch to sugars showed a low dependency for ethylene, but a high sensitivity to low concentrations of ethylene (0.01 microl l(-1)). By contrast, later ripening events such as flesh softening and ester volatile production showed a high dependency for ethylene but were less sensitive to low concentrations (needing 0.1 microl l(-1) for a response). A sustained exposure to ethylene was required to maintain ripening, indicating that the role of ethylene may go beyond that of ripening initiation. These results suggest a conceptual model for the control of individual ripening characters in apple, based on both ethylene dependency and sensitivity.

Show MeSH
Related in: MedlinePlus