Sequence analysis of expressed sequence tags from an ABA-treated cDNA library identifies stress response genes in the moss Physcomitrella patens

Partial cDNA sequencing was used to obtain 169 expressed sequence tags (EST s) in the moss, Phyiscomitrella patens. The source of ESTs was a random cDN A library constructed from 7 day-old protonemata following treatment with 1 0(-4) M abscisic acid (ABA). Analysis of the ESTs identified 69% with homol ogy to known sequences, 61% of which had significant homology to sequences of plant origin. More importantly, at least 11 ESTs had significant similar ities to genes which are implicated in plant stress-responses, including re sponses which may involved. These included a cDNA associated with desiccati on tolerance, two heat shock protein genes, one cold acclimation protein cD NA and five others that may be involved in either oxidative or chemical str ess or both. i.e., Zn/Cu-superoxide dismutase, NADPH protochlorophyllide ox idoreductase (PorB). selenium binding protein, glutathione peroxidase and g lutathione S transferase. Analysis of codon usage between P. patens and see d plants indicated that although mosses and higher plants are to a large ex tent similar, minor variations also exist that may represent the distinctiv eness of each group.