We have examined the role of alcohol dehydrogenase (ADH, E.C.22.214.171.124) in chilling tolerance using maize (Zea mays L.) Adh1-Adh2- doubly null mutant. Adh1-Adh2- doubly null seedlings were found to have lowered survival rates compared to non-doubly null maize seedlings (Silverado F1) when held at 2°C for varying periods. Exposure to ethanol did not increase the chilling tolerance in either Silverado F 1 or Adh1-Adh2- doubly null. ADH activity in Silverado F1 remained steady when held at 2°C for up to 3 d. ADH1 protein accumulation in chilled Silverado F1 seedlings remained unchanged throughout the period of cold exposure. Chilling led to a significant inhibition of the P-H+-ATPase (E.C. 126.96.36.199) activity in Adh1 -Adh2-doubly null, but minimal inhibition was seen in Silverado F1. Though P-H+-ATPase activity in Adh1 -Adh2- decreased, P-H+-ATPase protein levels remained constant during the chilling period. Levels of ATP slightly fluctuated in both types of seedlings during the duration of chilling. Lipid peroxidation levels in Adh1-Adh2- doubly null increased with chilling exposure, but not in the Silverado F1. We suggest that ADH activity may play a role in chilling tolerance that is not related to maintenance of glycolysis and ATP production as has been observed during oxygen depravation.
All Science Journal Classification (ASJC) codes
- Plant Science
- Alcohol dehydrogenase
- Zea mays L