Crocus sieberi subsp. sublimis Transcriptome or Gene expression. Crocus sieberi subsp. sublimis

Crocins, the red soluble apocarotenoids of saffron, accumulate in the flowers of Crocus species in a developmental and tissue-specific manner. In Crocus sieberi, crocins accumulate in stigmas but also in a distinct yellow tepal sector, that we show contains chromoplast converted from amyloplasts. The secondary metabolites were analyzed by LC-DAD-HRMS, revealing the progressive accumulation of crocetin and crocins in the yellow sector, which were also in situ localized by Raman microspectroscopy. To understand the underlying mechanisms of crocins biosynthesis, we sequenced the C. sieberi tepal transcriptome of two differentially pigmented sectors (yellow and white) at two developmental stages (VI and VIII) by Illumina sequencing. A total of 154 million high-quality reads were generated, and assembled into 248,099 transcripts. Differentially expressed gene (DEG) analysis resulted in the identification of several potential candidate genes involved in crocins metabolism and regulation. The results provide a first profile of the molecular events related to the dynamics of crocetin and crocins accumulation during tepal development. Further, presents new information on apocarotenoid biosynthesis regulators and accumulation in Crocus, and reveals unknown genes to affect crocins formation, which could be used to improve crocins accumulation in Crocus plants and the commercial quality of saffron spice.