Investigations of ABA insensitive revertants of era1 in Arabidopsis thaliana

grantor: University of TorontoA screen for suppressors of the ABA 'era1' supersensitive mutant in 'Arabidopsis thaliana' had previously been performed in an effort to identify targets of the ERA1 farnesyl transferase and to identify downstream components of the ERA1 ABA-dependent signalling pathway. Out of 124 lines that retested, eight suppressors of 'era1' are ABA-insensitive, and have been designated 'i_nsensitive r_evertants of e_ra1'. Genetic analysis revealed that 'ire' mutants suppress 'era1' dominantly, but their insensitive phenotype is recessive. 'ire' mutants represent three complementation groups, one of which is a new mutation in the seed-specific ABI3 transcription factor that has previously been shown to mediate ABA responses during seed development. In addition to the seed supersensitivity of 'era1, ire ' mutants suppress adult phenotypes of 'era1', including drought tolerance. This is the first demonstration that AB1I3 has a genetic role outside of the seed.M.Sc