| Saffron is a traditional crop from the geographic area of La Mancha, known to be one of the most expensive spices of the world, and very appreciated for its colouring and flavouring characteristics and medical properties. It is a monocot, triploid, sterile plant that is vegetatively propagated by means of a subterraneous organ specialized in the reserves accumulation, the corm. To help us to understand corm physiology and gene expression knowledge more deeply, six developmental stages were defined, including the complete development of this organ, from its appearance as latent buds, until its senescence and death. Gene expression was analysed in two of them, generating 650 partial sequences (ESTs) from two cDNA libraries. In the first one, constructed from corms collected in February, at a stage characterized by storage accumulation and enlargement (C3), a higher percentage of ESTs coding for proteins related to cell growth, protein metabolism, signal perception and transduction, defence against pathogens and stress, and carbohydrate metabolism was found. On the other hand, in the second library, constructed from corms collected in July, at a dormant stage (C4), a higher percentage of ESTs coding for proteins related to transport was found. In both libraries, a great percentage (36% in C3 and 50% in C4) did not show any significant similarity when compared to sequences present in public data bases, emphasizing the lack of knowledge about this organ. In addition, the major storage protein, a mannose-binding protein, was analysed. Its maximum expression occurs during summer months, when the corm is at a dormant stage. It is accumulated in the corm until flowering and disappears after it, in concordance to its storage role. |
