Increase in ACC oxidase levels and activities during paradormancy release of leafy spurge (Euphorbia esula) buds

Abstract

The plant hormone ethylene is known to affect various developmental processes including dormancy and growth. Yet, little information is available about ethylene's role during paradormancy release in underground adventitious buds of leafy spurge. In this study, we examined changes in ethylene evolution and the ethylene biosynthetic enzyme ACC oxidase following paradormancy release (growth induction). Our results did not show an obvious increase in ethylene during bud growth. However, when buds were incubated with 1 mM ACC, ethylene levels were higher in growing than non-growing buds, suggesting that the levels of ACC oxidase increased in growing buds. Real-time qPCR indicated that the transcript of a Euphorbia esula ACC oxidase (Ee-ACO) increased up to 3-fold following growth induction. In addition, a 2.5-to 4-fold increase in ACO activity was observed 4 days after decapitation, and the Ee-ACO accounted for as much as 40% of the total ACO activity. Furthermore, immunoblot analyses identified a 36-kD Ee-ACO protein that increased in expression during bud growth. This protein was highly expressed in leaves, moderately expressed in crown buds, stems and meristems, and weakly expressed in roots and flowers. Immunolocalization of Ee-ACO on growing bud sections revealed strong labeling of the nucleus and cytoplasm in cells at the shoot apical meristem and leaf primordia. An exception to this pattern occurred in cells undergoing mitosis, where labeling of Ee-ACO was negligible. Taken together, our results indicate an increase in the levels of Ee-ACO during paradormancy release of leafy spurge that was not correlated with an increase in ethylene synthesis.

Ethylene-Induced Hydrogen Sulfide Negatively Regulates Ethylene Biosynthesis by Persulfidation of ACO in Tomato Under Osmotic Stress

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Central-marginal population dynamics in species invasions

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Combination of Sodium Nitroprusside and Controlled Atmosphere Maintains Postharvest Quality of Chestnuts through Enhancement of Antioxidant Capacity

“…Considering the role of ethylene as an enhancer of fruit respiration [ 47 ], controlling its production might be essential to ensure the storage quality of fruits [ 48 , 49 ]. In previous studies, a controlled atmosphere has been widely used in postharvest preservation, showing reduced ethylene accumulation [ 50 , 51 ] by blocking its biosynthesis and absorption ( Figure 6 ) [ 52 , 53 , 54 ]. This explained the lower respiration rate for chestnuts in treated groups ( Figure 1 C), relative to CT.…”