Functional analysis of MYB transcription factors in Arabidopsis

MYB proteins are a class of transcription factors with a characteristic DNA-binding domain. In vertebrates MYB proteins form a small family with a central role in controlling cellular proliferation, cell cycle progression and differentiation.The information available on the function of plant MYB proteins suggested a role in plant-specific processes. The aim of Ph.D project has beeen the functional characterization of AtMYB41 and AtMYB60. AtMYB41 is not expressed in wild type plants grown in normal conditions. Its transcript is accumulated in response to drought, NaCl and PEG treatments, but not after ABA supply. The overexpression of AtMYB41 in transgenic plants results in severe growth inhibition and in the deposition of a discontinue cuticle. AtMYB60 is specifically expressed in stomata guard cells and the transcript is accumulated under conditions promoting stomatal aperture whereas its abundance is reduced by stimuli triggering stomatal closure.Loss-of-function atmyb60-1 mutation resulted in the impairment of stomatal opening and in reduced wilting during water stress.