Mutations in EIN2 lead to an overaccumulation of ABA in
leaves, suggesting that ERA3/EIN2 is a negative regulator of
ABA synthesis. Moreover, mutations that decrease ET
sensitivity (e.g. ein2) increase the sensitivity of seed to ABA
and mutation in ET RECEPTOR 1 (ETR1) results in an eightfold
higher level of ABA in the mature dry seeds than in wild
type seeds [40]. This is consistent with the observations that ET
acts antagonistically to ABA during Arabidopsis seed development
and may be one of the main reasons why etr1-2 seeds
display a greater degree of dormancy than wild type