ABSTRACT
We present a global characterization of A. annua GT transcriptome using 454 pyrosequencing. Sequencing runs using two normalized cDNA collections from GTs yielded 406,044 expressed sequence tags (ESTs) (average length = 210 nucleotides), which assembled into 42,678 contigs and 147,699 singletons. Performing a second sequencing run only increased the number of genes identifi ed by ~30%, indicating that massively parallel pyrosequencing provides deep coverage of the A. annua trichome transcriptome. By BLAST search against the NCBI non-redundant protein database, putative functions were assigned to over 28,573 unigenes, including previously undescribed enzymes likely involved in sesquiterpene biosynthesis. Comparison with ESTs derived from trichome collections of other plant species revealed expressed genes in common functional categories across different plant species. The RT-PCR analysis confi rmed the expression of selected unigenes and novel transcripts in A. annua GTs.
