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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

Sensitivity (A), responsivity (B), and dependency (C) of the MdACO1as apples to exogenous ethylene. Sensitivity and responsivity was determined as the ethylene concentration required for a 50% response and the rate of change, respectively, using non-linear regression and a logistic function. Ethylene dependency (%) was calculated as the difference between the 0 μl l−1 and 1000 μl l−1 ethylene treatments divided by the 1000 μl l−1 ethylene treatment, and multiplying by 100 to give a percentage: 0%=ethylene independent, 100%=ethylene dependent.
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fig5: Sensitivity (A), responsivity (B), and dependency (C) of the MdACO1as apples to exogenous ethylene. Sensitivity and responsivity was determined as the ethylene concentration required for a 50% response and the rate of change, respectively, using non-linear regression and a logistic function. Ethylene dependency (%) was calculated as the difference between the 0 μl l−1 and 1000 μl l−1 ethylene treatments divided by the 1000 μl l−1 ethylene treatment, and multiplying by 100 to give a percentage: 0%=ethylene independent, 100%=ethylene dependent.

Mentions: The differential sensitivity of the different ripening traits was further quantified using non-linear regression to estimate the ethylene concentration required to induce a half-maximum response. This approach showed that the half-maximal response for starch clearance occurred at low ethylene concentrations, with skin yellowing, softening, and volatile production requiring progressively higher ethylene concentrations to induce a similar 50% response (Fig. 5A). The rate of change parameter estimated from this analysis was similar for all ripening characters (Fig. 5B), suggesting the responsivity to ethylene was similar despite differences in sensitivity.


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)

Sensitivity (A), responsivity (B), and dependency (C) of the MdACO1as apples to exogenous ethylene. Sensitivity and responsivity was determined as the ethylene concentration required for a 50% response and the rate of change, respectively, using non-linear regression and a logistic function. Ethylene dependency (%) was calculated as the difference between the 0 μl l−1 and 1000 μl l−1 ethylene treatments divided by the 1000 μl l−1 ethylene treatment, and multiplying by 100 to give a percentage: 0%=ethylene independent, 100%=ethylene dependent.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig5: Sensitivity (A), responsivity (B), and dependency (C) of the MdACO1as apples to exogenous ethylene. Sensitivity and responsivity was determined as the ethylene concentration required for a 50% response and the rate of change, respectively, using non-linear regression and a logistic function. Ethylene dependency (%) was calculated as the difference between the 0 μl l−1 and 1000 μl l−1 ethylene treatments divided by the 1000 μl l−1 ethylene treatment, and multiplying by 100 to give a percentage: 0%=ethylene independent, 100%=ethylene dependent.
Mentions: The differential sensitivity of the different ripening traits was further quantified using non-linear regression to estimate the ethylene concentration required to induce a half-maximum response. This approach showed that the half-maximal response for starch clearance occurred at low ethylene concentrations, with skin yellowing, softening, and volatile production requiring progressively higher ethylene concentrations to induce a similar 50% response (Fig. 5A). The rate of change parameter estimated from this analysis was similar for all ripening characters (Fig. 5B), suggesting the responsivity to ethylene was similar despite differences in sensitivity.

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