The isolation and characterization of abscisic acid‐insensitive mutants of <i>Arabidopsis thaliana</i>

TLDR

ABA‑insensitive mutants of *Arabidopsis thaliana* have been identified. The study examines how the genes responsible for these mutants influence ABA signaling. Mutagenized seeds were screened on 10 µM ABA, yielding five mutants at three loci from approximately 3,500 progeny. Three mutants exhibited reduced seed dormancy and withering symptoms resembling ABA‑deficient phenotypes, two showed only reduced dormancy, and all mutants had equal or higher endogenous ABA levels in developing seeds and fruits compared to wild type.

Abstract

Abscisic acid (ABA) insensitive mutants of Arabidopsis thaliana (L.) Heynh. were isolated by selecting plants which grew well on a medium containing 10 μ M ABA. From the progeny of approximately 3500 mutagen‐treated seeds, five mutants of at least three different loci were isolated. Three mutants were characterized, moreover, by a reduced seed dormancy and by symptoms of withering, indicating disturbed water relations and, therefore, resembled phenotypically the ABA‐deficient mutants we described earlier in this species. Two mutants showed in addition only a reduction of seed dormancy. Compared to wild type, all mutants showed similar or increased levels of endogenous ABA in developing seeds and fruits (siliquae). The role of the different genes involved is discussed in relation to the mechanism of ABA action.