PUB - Publikationen an der Universität Bielefeld

Salt stress is an environmental factor that severely impairs plant growth and productivity. Salinity-induced transcript accumulation was monitored in the salt-sensitive Arabidopsis thaliana and the related salt-tolerant Lobularia maritima using cDNA-arrays with expressed sequence tags derived from a cDNA subtraction library of salt-stressed L maritima. The expression profiles revealed differences of the steady state transcript regulation in A. thaliana and L maritima in response to salt stress. The differentially expressed transcripts include those involved in the control of gene expression as a transcription factor 11 homologue as well as signal transduction elements such as a serine/threonine protein kinase. a SNF1-related protein kinase AKIN10 homologue. and protein phosphatase 2C. Other ESTs with differential regulation patterns included transcripts encoding proteins with function in general stress responses and defense and included a peroxidase, dehydrins, enzymes of lipid and nitrogen metabolism, and functionally unclassified proteins. In a more detailed analysis the basic leucine zipper transcription factor AtbZIP24 showed differential transcript abundance in A. thaliana and L maritima in response to salt stress. Transgenic AtbZIP24-RNAi lines showed improved growth and development under salt stress that was correlated with changed Cl- accumulation. The data indicate that AtbZIP24 functions as a transcriptional repressor in salt-stressed A. thaliana that negatively regulates growth and development under salinity in context of controlling Cl- homeostasis. Monitoring the differential and tissue specific global regulation of gene expression during adaptation to salinity in salt-sensitive and halotolerant plants is a promising and powerful approach to identify novel elements of plant salt stress adaptation. (c) 2008 Elsevier B.V. All rights reserved.