IDENTIFICATION OF THE SECONDARY METABOLITE CAPSIATE IN CAPSICUM GERMPLASM ACCESSIONS

Besides capsaicin (CAP), capsiate (CAT) is now recognized as an important secondary metabolite of pepper (Capsicum spp.) for use as a health food, dietary supplement, and pharmaceutical. However, genetic resources for high levels of CAT are scarce worldwide. Sources of variation are needed to develop new commercial pepper varieties with high levels of CAT. This study was primarily conducted to evaluate high CAT yields with or without CAP. Moreover, two DNA markers, which were associated with CAT and CAP, were used to identify the presence of these two secondary metabolites. Results indicated that the accession KKU-P31146 contained the highest levels of CAT (505.3 mu g/g DW) without Sum CAPs among the 19 tested accessions. Although the KKU-P62268 pepper accession showed the highest Sum CATs (3794.1 mu g/g DW), it contained lower levels of CAT than KKU-P31146. The dCAPS (p-AMT) molecular marker amplified a DNA fragment of 269 bp, whereas a 1670 bp DNA fragment was not amplified by the SCAR (Pun1) molecular marker. In addition, the genotypic data from the two known molecular markers were associated with CAT and Sum CAPs in all tested accessions. In particular, this association was clearly observed in KKU-P31146. The novel discovery here is that KKU-P31146 should be considered as a new source for breeding high-CAT accessions due to its high CAT and no CAP. An obvious association between the CAT-related genotypic and phenotypic traits of KKU-P31146 indicated that the two known markers are useful for the selection of pepper accessions with the target trait.