Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0277787 (stigma)
 13,352 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Crocus sativus stigmas are the main source of crocins, which are glucosylated apocarotenoids derived from zeaxanthin cleavage that give saffron its red color. Phytoene synthase (PSY) mediates the first committed step in carotenoid biosynthesis in plants. Four PSY genes encoding functional enzymes were isolated from saffron. All the proteins were localized in plastids, but the expression patterns of each gene, CsPSY1a, CsPSY1b, CsPSY2, and CsPSY3, in different saffron tissues and during the development of the stigma showed different tissue specialization. The CsPSY2 transcript was primarily detected in the stigmas where it activates and stimulates the accumulation of crocins, while its expression was very low in other tissues. In contrast, CsPSY1a and CsPSY1b were mainly expressed in the leaves, but only CsPSY1b showed stress-light regulation. Interestingly, CsPSY1b showed differential expression of two alternative splice variants, which differ in the intron retention at their 5' UTRs, resulting in a reduction in their expression levels. In addition, the CsPSY1a and CsPSY1b transcripts, together with the CsPSY3 transcript, were induced in roots under different stress conditions. The CsPSY3 expression was high in the root tip, and its expression was associated with mycorrhizal colonization and strigolactone production. CsPSY3 formed a separate branch to the stress-specific Poaceae homologs but was closely related to the dicot PSY3 enzymes.
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PMID:The Specialized Roles in Carotenogenesis and Apocarotenogenesis of the Phytoene Synthase Gene Family in Saffron. 3088 24

Colored apocarotenoids accumulate at high concentrations in few plant species, where display a role in attraction of pollinators and seed dispersers. Among these apocarotenoids, crocins accumulate at high concentrations in the stigma of saffron and are responsible for the organoleptic and medicinal properties of this spice. Phytoene synthase and Orange protein are key for carotenoid biosynthesis and accumulation. We previously isolated four phytoene synthase genes from saffron with differential roles in carotenoid and apocarotenoid biosynthesis. However, the implications of Orange genes in the regulation of apocarotenoid accumulation are unknown. Here, we have identified two Orange genes from saffron, with different expression patterns. CsOr-a was mainly expressed in vegetative tissues and was induced by light and repressed by heat stress. Both CsOr-a and CsOr-b were expressed in stigmas but showed a different profile during the development of this tissue. The interactions of CsOr-a and CsOr-b were tested with all the four phytoene synthase proteins from saffron and with CsCCD2. None interactions were detected with CCD2 neither with the phytoene synthase 2, involved in apocarotenoid biosynthesis in saffron. The obtained results provide evidence of different mechanisms regulating the phytoene synthase enzymes in saffron by Orange for carotenoid and apocarotenoid accumulation in saffron.
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PMID:Differential interaction of Or proteins with the PSY enzymes in saffron. 3195 12