|Farrell, Robert - PENNSYLVANIA ST. UNIV.|
|NORELLI, JOHN (JAY)|
Submitted to: Plant and Animal Genome Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: November 12, 2004
Publication Date: N/A
Technical Abstract: Living cells respond to environmental stresses by up-regulating specific subsets of genes while down-regulating others. Global approaches to identifying these different groups of genes have been successfully applied to several plant systems. One approach involves subtracting cDNAs expressed in one state from cDNAs expressed in another. By varying which cDNA serves as the driver and which one serves as the tester in the hybridization reaction, one can obtain both up-regulated (forward subtraction) and down-regulated (reverse subtraction) genes in response to a given treatment. To profile gene expression at different temperatures and photoperiods, we created subtracted libraries from peach bark tissues sampled from trees kept at 5°C and 25°C under a short day (SD) photoperiod or exposed to a night break (NB) interruption during the dark period of the SD cycle, thus simulating a long photoperiod. Sequences expressed in forward and reverse subtractions using various subtracted combinations of temperature and photoperiod treatments were cloned, sequenced, and identified by BLAST analysis. Some defense-related genes (e.g. ß-1,3 glucanase) were up-regulated by both cold and SD treatments, whereas, other genes responded positively only to exposure to cold (dehydrins) or SDs (classII chitinase). Several genes of known function, whose association with cold acclimation has not been previously recognized, were shown to be up-regulated at 5°C. A few of these genes appear to have regulatory roles, e.g. transcription factors and signal transducers. These results are discussed in relation to our previous observations on genes expressed in peach bark under winter field conditions.