ORIGINAL ARTICLE Transcript profiling of carotenoid/apocarotenoid biosynthesis genes during corm development of saffron (Crocus sativus L.) Munish Sharma 1 & Sanjana Kaul 1 & Manoj Kumar Dhar 1 Received: 21 March 2018 /Accepted: 29 July 2018 # Springer-Verlag GmbH Austria, part of Springer Nature 2018 Abstract The dried stigmas of saffron constitute the world’ s costliest spice. Saffron has many therapeutic applications due to the presence of apocarotenoids. The latter are synthesized at different stages of development, and the biosynthetic pathway involves several genes encoding different enzymes. In order to understand the differential expression of various genes of the pathway, eight distinct developmental stages (S1-early to S8-late) were identified. The corms were assorted into three groups (I, II, and III) based on corm weight. Expression profiles of 12 carotenoid/apocarotenoid genes were studied. The expression of all genes was minimum/least in groups I and II corms during bud development. Lowest expression of carotenogenic genes (CsPSY , CsPDS, CsZDS, CsCRTISO, CsLYC-β1, CsLYC-ε, CsBCH2, and CsNCED) was observed during early stages (S1–S3) of corm growth (dormant period). In group III corms, increased expression of apocarotenoid genes (CsZCO, CsCCD2, CsUGT , and CsALDH) was observed during S4 to S8 stages (reproductive period, floral differentiation). Besides, expression profiles of genes in apical and axillary buds were also examined. Of all the genes studied, apocarotenoid biosynthesis genes (CsBCH2, CsZCO, CsCCD2, CsALDH, and CsUGT) were found to be upregulated in apical bud than in the axillary bud. The results indicated that interaction of phytohormones and sugars, mother corm reserves and the influence of internal and external factors may be contributing to the growth of saffron corm/bud. The study has laid a foundation for further research on the molecular mechanisms underlying bud dormancy/growth in saffron. Keywords Apocarotenoids . Biosynthetic pathway . Bud development . Crocus sativus . Real-time PCR Introduction Saffron (Crocus sativus) of family Iridaceae is an autumn flowering geophyte, which bears purple colored flowers. Owing to extremely high demand from the dye, perfumery and flavoring industries, saffron is considered to be one of the most expensive spices, popularly known as BGolden condiment^ (Ahmad et al. 2014). The major saffron producing countries are Iran, Greece, Spain, Turkey, India, France, Morocco, Switzerland, Israel, Afghanistan, and Iraq (Caballero-Ortega et al. 2007). In India, saffron is cultivated only in the state of Jammu and Kashmir, and is one among the most important cash crops (Koul and Farooq 1984; Dhar et al. 1988). Since time immemorial, saffron has been regarded as an important medicinal plant having number of therapeutic applications (Fernandez 2004). Traditionally, saffron has been used against cramps, bronchospasms, liver, and menstruation disorders (Abdullaev et al. 2003). Saffron also exhibits antiox- idant and free-radical scavenging activities as its metabolites prevent lipid peroxidation and human platelet aggregation (Tabassum and Hamdani 2014). Saffron is a triploid (2n = 3x = 24), sterile plant, vegetative- ly propagated by underground corms (Brighton 1977; Grilli Caiola 2004), which is subterraneous stem that accumulate reserves (starch-containing parenchyma cells) for sprouting after dormancy. Mature saffron corms usually show one to three apical dominant buds (which sprout in the following season) and many axillary dormant buds (Fig. 1). Generally, only four to five daughter corms per mother corm are obtained Handling Editor: Burkhard Becker Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00709-018-1296-z) contains supplementary material, which is available to authorized users. * Manoj Kumar Dhar manojkdhar@rediffmail.com 1 Genome Research Laboratory, School of Biotechnology, University of Jammu, Jammu 180006, India Protoplasma https://doi.org/10.1007/s00709-018-1296-z