Relationship between alcohol dehydrogenase activity and low-temperature in two maize genotypes, Silverado F1 and Adh1–Adh2– doubly null

We have examined the role of alcohol dehydrogenase (ADH, E.C.1.1.1.1) 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 F1 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. 3.6.3.6) 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.