ABSTRACT Dehydrins are plant specific proteins, distinguished by the presence of a consensus sequence, known as the K-region or K-peptide. Expression patterns of dehydrins in Arabidopsis thaliana divide the dehydrins into two highly correlative groups; however, unique patterns of expression are found within these groups. Some dehydrins are more responsive during development than to abiotic stresses. The KS-type dehydrin transcripts are highly expressed but are unresponsive to various stresses. The KS-type dehydrins are not enriched in promoter cis-elements similar to the other dehydrins suggesting they may be regulated through distinct pathways from the rest of the dehydrin family. In general, the three most acidic dehydrins have the greatest transcript levels in vegetative tissues (both roots and aerial tissues) and levels sharply decline during seed development. RAB18 and the basic dehydrins are at highest levels in the seed. A finding of a concomitant pattern of expression of the seed dehydrins on one hand and the vegetative dehydrins on the other, suggest a unique coordinated role for dehydrins in seedling development. In general, the alteration of dehydrin proteins appears to be necessary during development, as well as, during abiotic stress. While the majority of focus in the past has centered on identifying the role of dehydrins in environmental stresses, it is worth considering what functions are being accomplished by some dehydrins during development that may increase in demand during abiotic stress.
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