PLANT TOLERANCE TO DROUGHT: MODULATION OF TRANSCRIPTION FACTORS

Water scarcity is a serious problem that will be exacerbated by global climate change. Massive quantities of water are used in agriculture, and abiotic stresses, especially drought and increased salinity, are primary causes of crop loss worldwide. Various approaches may be adopted to consume less water in agriculture, one of them being the development of plants that use less water yet maintain high yields in conditions of water scarcity. In recent years several molecular networks concerned with stress perception, signal transduction and stress responses in plants have been elucidated. In this PhD thesis the various approaches used so far to produce transgenic plants having improved tolerance to abiotic stresses, and criteria for choosing which genes and promoters have been used to obtain successful results are discussed. Then research results on the promoter of the Arabidopsis AtMYB60 gene, specifically expressed in guard cells and on the promoter of the Arabidopsis AtMYB41 gene, specifically expressed in response to abiotic stresses, are presented. The AtMYB60 promoter was characterised through serial deletion and mutagenesis analysis and some DOF-binding sites, fundamental cis-elements for the specific activity of this promoter in guard cells were identified. Through analysis of transegnic plants carrying the AtMYB41 promoter fused to a reporter gene specific response to drought stress was confirmed.