Plant & Animal Genomes XV Conference Plant & Animal Genomes XV ConferenceJanuary 13-17, 2007
Town & Country Convention Center
San Diego, CA
Livia Tommasini , Jan Svensson , Edmundo Rodriguez , Timothy J Close
Low temperature and drought have major influence on plants growth and productivity. To identify genes involved in stress response, we addressed changes in gene expression and crosstalk between stress signal pathways induced by low temperature and drought in barley. Different studies have focused on gene expression in short-term stress, whilst no transcriptome data are available on long term drought and cold stress, including protein synthesis during freeze/thaw cycles mimicking field conditions. Therefore, in this study we used the Affymetrix Barley 1 GeneChip to investigate transcriptome responses of barley cv. Morex 1) to drought over 21 days based on five triplicated stress treatments and a wide range of soil water content treatments, and 2) to low temperature including triplicated measurements of cold, freeze/thaw cycles and de-acclimation over 33 days. We found that 65% of 2-fold up regulated genes was induced specifically by drought stress, whereas only 7.9% was cold-specific and 6.5% was freeze/thaw-specific. Only 8.2% of the genes were commonly up regulated by freeze/thaw and drought. The largest crosstalk was observed between cold and freeze/thaw (16.7%). About 75 % of the responsive probe sets were similar to annotated genes, 15 % had similarity to genes of unknown function, and 10 % represented novel genes. Gene function of up regulated transcripts and over represented functional categories in the set of responsive genes versus the full array were identified and discussed. Among drought-responsive transcripts, dehydrins (dhns) were the most common gene name. The specific expression of each of the 13 barley dhns was examined in each low temperature and drought condition.