Comparative analyses of six solanaceous transcriptomes reveal a high degree of sequence conservation and species-specific transcripts.
BACKGROUND
The Solanaceae is a family of closely related species with diverse phenotypes that have been exploited for agronomic purposes. Previous studies involving a small number of genes suggested sequence conservation across the Solanaceae. The availability of large collections of Expressed Sequence Tags (ESTs) for the Solanaceae now provides the opportunity to assess sequence conservation and divergence on a genomic scale.


RESULTS
All available ESTs and Expressed Transcripts (ETs), 449,224 sequences for six Solanaceae species (potato, tomato, pepper, petunia, tobacco and Nicotiana benthamiana), were clustered and assembled into gene indices. Examination of gene ontologies revealed that the transcripts within the gene indices encode a similar suite of biological processes. Although the ESTs and ETs were derived from a variety of tissues, 55-81% of the sequences had significant similarity at the nucleotide level with sequences among the six species. Putative orthologs could be identified for 28-58% of the sequences. This high degree of sequence conservation was supported by expression profiling using heterologous hybridizations to potato cDNA arrays that showed similar expression patterns in mature leaves for all six solanaceous species. 16-19% of the transcripts within the six Solanaceae gene indices did not have matches among Solanaceae, Arabidopsis, rice or 21 other plant gene indices.


CONCLUSIONS
Results from this genome scale analysis confirmed a high level of sequence conservation at the nucleotide level of the coding sequence among Solanaceae. Additionally, the results indicated that part of the Solanaceae transcriptome is likely to be unique for each species.
Rensink
Willem Albert
WA
The Institute for Genomic Research, Rockville, MD 20850, USA. wrensink@tigr.org
Lee
Yuandan
Y
Liu
Jia
J
Iobst
Stacy
S
Ouyang
Shu
S
Buell
C Robin
CR
D017124:Conserved Sequence; D018076:DNA, Complementary / Q000378:metabolism; D020224:Expressed Sequence Tags; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D015723:Gene Library; D017343:Genes, Plant; D016678:Genome; D018745:Genome, Plant; D020407:Internet; D008957:Models, Genetic; D009693:Nucleic Acid Hybridization; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D010802:Phylogeny; D010940:Plant Proteins; D012333:RNA, Messenger / Q000378:metabolism; D017422:Sequence Analysis, DNA; D012984:Software; D019657:Solanaceae / Q000235:genetics*
D018076:DNA, Complementary; D010940:Plant Proteins; D012333:RNA, Messenger