Expressed sequence tags (ESTs) from cold-acclimated barley to identify novel plant genes

Expressed sequence tags (ESTs) databases are being created for severalplant species. ESTs have the potential to analyse the expressed part ofthe genome, and to be used in a wide range of applications from thetheoretical aspect of plant biology to the breeding process. The presentstudy is based on a cold-stressed cDNA library as a source of ESTs inbarley: partial cDNA sequencing of randomly isolated clones yielded960 ESTs. The strategy of random sequencing cDNA clones at their5' ends allows one to obtain information on the steady-state level of thetranscripts in a cold-stressed green leaf of barley. Repetitive sequencingof nearly identical ESTs provides, in addition, useful information onthe existence of multigene families. The results of a BLAST searchperformed on this set of ESTs showed that 18.5% of the tags exhibitedno significant homology to known genes, 10% had significant levels ofhomology with known cold or other stress-related genes, about 26%proved homologous to enzymes involved in several metabolic pathways and about 15% encoded for ribosomal proteins, cytoskeletonproteins, histones, ubiquitin, elongation factors and others. Redundancy was found for some classes of tag: RuBisCo, cab proteins,carbonic anhydrase, glutamate decarboxylase and stress relatedproteins.