|
|
||||||||
|
Plant Physiology 96:269-274 (1991) © 1991 American Society of Plant Biologists Suppression of Cellulase and Polygalacturonase and Induction of Alcohol Dehydrogenase Isoenzymes in Avocado Fruit Mesocarp Subjected to Low Oxygen StressInstitute of Molecular Biology and Biotechnology, P. O. Box 1527, 711 10 Heraklion, FO.R.T.H., Greece, Department of Horticulture, University of Maryland, College Park, Maryland 20742, Department of Biology, University of Crete, 714 09 Heraklion, Greece Expression of polygalacturonase and cellulase, two hydrolytic enzymes of avocado (Persea americana, cv Hass) fruit which are synthesized de novo during ripening, and alcohol dehydrogenase, a known anaerobic protein, were studied under different O2 regimes. Low O2 concentrations (2.5-5.5%) diminished the accumulation of polygalacturonase and cellulase proteins and the expression of their isoenzymes. This pattern of change in cellulase protein was also reflected in the steady-state amount of its mRNA. In contrast, 7.5 and 10% O2 did not alter the changes observed in fruits ripened in air. On the other hand, alcohol dehydrogenase was induced in 2.5, 3.5, and 5.5% O2 but not in 7.5 or 10% O2. The recovery from the hypoxic stress upon returning the fruits back to air for 24 hours, was also a function of O2 tensions under which the fruits were kept. Thus, the synthesis of polygalacturonase and cellulase was directly related to O2 levels, while the activity of the isoenzymes of alcohol dehydrogenase was inversely related to O2 levels. The results indicate that hypoxia exerts both negative and positive effects on the expression of certain genes and that these effects are initiated at the same levels of O2.
This article has been cited by other articles:
|
|||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| ASPB Publications | PLANT PHYSIOLOGY | THE PLANT CELL | |
|---|---|---|---|