Ethylene-Insensitive Arabidopsis Mutants etr1-1 and ein2-1 Have a Decreased Freezing Tolerance.

The freezing tolerance of Arabidopsis thaliana (L.) Heynh. was studied in relation to functioning of the ethylene signaling pathway. Constitutive freezing tolerance was compared in wild-type plants (ecotype Col-0) and ethylene-insensitive mutants etr1-1 and ein2-1. For the first time it was established that the ethylene-insensitive mutants had a 25-30% lower net photosynthesis rate, a decreased content of soluble sugars, and, as a result, a lower freezing tolerance. Our work provides evidence that the perception and transduction of ethylene signal are necessary for constitutive tolerance of Arabidopsis to low temperature.