Analysis of 176 expressed sequence tags generated from cDNA clones of hot pepper by single-pass sequencing

As a part of the project to identify novel genes from the hot pepper (Capsicum annuum L. cv. Happy Dry), we have constructed several cDNA libraries and 176 randomly selected cDNA clones were partially sequenced. This expressed sequence tag (EST) analysis identified 95 clones (54.0%) that had a significant homology to a known protein sequence in the NCBI database. Of these clones, eighteen of them are related to genes not from the plant kingdom, indicating that 10.2% of the ESTs were newly identified in plants. Eunctional categorization of these clones revealed that the genes involved in metabolic pathways such as glycolysis and photosynthesis are most abundant, and genes in translational apparatus ranked next in abundance. Expression patterns of four ESTs were examined by RNA blot analysis. The CAN14 clone, which has a 58% identity to the potato patatin protein over a 117 amino acid overlap, was highly expressed in anther tissue but not in fruit tissues. The CFR2 clone, which is 88% identical to apospory-associated protein, showed relatively higher expression levels in seedlings and roots compared to other tissues. The transcript of the CFR11 clone, which shows a homology to γ-thionin, was abundant in every organ that was examined except roots. The CFR 29 clone which is 92% identical to the putative osmoprotectant from tomato root showed a root-preferential expression pattern.