cDNA library construction and EST analysis from an Arctic moss, Aulacomnium turgidum

Abstract

Unique physiological and metabolic properties of Arctic mosses are responsible for their acclimation to the inclement polar environment. To perform transcriptome analysis from a polar moss species adapted to Arctic environment, we constructed a cDNA library using total RNA with high quality from an Arctic moss, Aulacomnium turgidum. The results showed that the library had 1.81×106 of independent clones with 97.41% of recombinants. A total of 509 cDNA clones were sequenced. After eliminating poor quality sequences, vector trimming and clustering, 360 unigenes consisting of 33 contigs and 327 singletons were identified. BLASTX searches generated 245 significant hits (E-value <10-5). For further Gene Ontology analysis, 158 unigenes were annotated and classified with terms for molecular function, biological process and cellular component. Among the ESTs, seven genes were selected based on their putative roles in stress response, and they showed enhanced transcripts level under various abiotic stresses such as low temperature, heat, and high salt. Also, two rare cold inducible genes showed different expression patterns under low temperature and UV-B treatment, indicating their distinct roles in adaptation to Arctic environment. Although experiments have been conducted on a limited scale, this study provides useful information for better understanding the mechanism of stress acclimation of polar mosses and material basis for potential genomic modification for higher plants to increase stress tolerance.