2-DIMENSIONAL PROTEIN-PATTERNS OF ARABIDOPSIS WILD-TYPE AND AUXIN INSENSITIVE MUTANTS, AXR1, AXR2, REVEAL INTERACTIONS BETWEEN DROUGHT AND HORMONAL RESPONSES

In order to detect gene products involved in Arabidopsis drought adapt ive strategy, 2D-PAGE protein patterns of two auxin-insensitive mutant s, axr1, axr2, differentially affected in specific drought responses, were compared to the wild-type Columbia ecotype, in well-watered and d rought-stressed conditions, Coupled to computer analysis of polypeptid e amounts, 2D-electrophoresis revealed subtle changes in protein expre ssion induced by progressive drought stress and/or mutations affecting the auxin response pathway. The differential protein patterns of axr1 and axr2 were consistent with their contrasting drought responses, Th e specific leaf and root protein patterns of axr1 showed that this mut ation disrupts drought responses related to auxin regulation, In parti cular, the near absence of drought rhizogenesis in axr1 was associated with a root protein pattern closer to the well-watered than to the wa ter-stressed axr2 and Columbia wild-type root protein patterns, Also, the largely different effects of axr1 and axr2 mutations suggest that they affect different pathways in auxin response, Several sets of poly peptides, whose regulation was affected by drought and/or mutation, we re thus detected, These polypeptides could play a role both in the aux in and the drought response pathways, Their identification, through mi crosequencing, should be most informative.