Analysis of expressed sequence tags from a normalized cDNA library of perilla (Perilla frutescens)

Abstract

Perilla (Perilla frutescens), an herbal plant belonging to the Lamiaceae family, has long been cultivated in Asia. Perilla is notable as an aroma-rich leaf vegetable and as the oilseed crop richest in omega-3 fatty acids. However, molecular analysis of this herbal plant is lacking due to insufficient genetic resources. Here, we constructed a normalized cDNA library from whole young perilla plants and analyzed expressed sequence tags (ESTs). A total of 4,582 uniESTs were generated from analysis of 5,435 ESTs. Among these, 307 uniESTs (6.7%) were identified as unique in perilla and 3,625 uniESTs were assigned at least one GO term through similarity searches in public databases. The most frequent GO terms were related to abiotic and biotic stress responses. In addition, we identified 141 uniESTs involved in lipid metabolism, of which four genes encoded fatty acid desaturases. We found one new candidate omega-3 fatty acid desaturase gene, in addition to the four that were previously reported. This analysis of uniESTs from perilla provides a valuable genetic resource to elucidate the molecular underpinnings of lipid metabolism and for molecular breeding of perilla species.