Plant & Animal Genomes XIV Conference Plant & Animal Genomes XIV ConferenceJanuary 14-18, 2006
Town & Country Convention Center
San Diego, CA
Victoria A James , Fredy Altpeter
Bahiagrass is an important turf and forage grass in the south-eastern US and in subtropical regions around the world. The productivity and persistence of bahiagrass is limited by environmental stresses like drought, freezing and in salt affected areas. We isolated several transcription activators of genes involved in abiotic stress response and will present data on over-expression of the CBF3 transcription activator in bahiagrass. Over-expression of the CBF3 (DREB1A ) transcriptional activator of the C/DRE stress response pathway has been successfully used in several plants for enhancing abiotic stress tolerance and therefore suggests it as a benchmark to compare alternative transcription factor candidates. Transcription factors, like CBF3, are capable of activating the expression of multiple genes involved in protection against environmental stresses. In order to explore the applicability of this system in bahiagrass, a CBF3 transcription factor ortholog was isolated from xeric, wild barley and placed under control of the drought, cold and salt inducible barley HVA1 promoter. The combination of the CBF3 transcription factor gene with a stress-inducible promoter might avoid negative effects during non-stress conditions. The HVA1-CBF3 expression unit was introduced into the apomictic bahiagrass cv. ‘Argentine’ via biolistic gene transfer and transgenic plants over-expressing CBF3 have been identified by real time RT-PCR. In contrast to wildtype plants, CBF3-expressing plants survived severe salt stress (200mM NaCl) under hydroponics conditions. Transgenic bahiagrass plants are currently being evaluated under field conditions in Northern Florida to determine tolerance to freezing temperatures. In addition we will present data on dehydration stress under controlled environment conditions.