Abstract
Saffron, derived from the stigma of Crocus sativus, is not only a valuable traditional Chinese medicine but also the expensive spice and dye. Its yield and quality are seriously influenced by its flowering transition. However, the molecular regulatory mechanism of the flowering transition in C. sativus is still unknown. In this study, we performed morphological, physiological and transcriptomic analyses using apical bud samples from C. sativus during the floral transition process. Morphological results indicated that the flowering transition process could be divided into three stages: an undifferentiated period, the early flower bud differentiation period, and the late flower bud differentiation period. Sugar, gibberellin (GA3), auxin (IAA) and zeatin (ZT) levels were steadily upregulated, while starch and abscisic acid (ABA) levels were gradually downregulated. Transcriptomic analysis showed that a total of 60 203 unigenes were identified, among which 19 490 were significantly differentially expressed. Of these, 165 unigenes were involved in flowering and were significantly enriched in the sugar metabolism, hormone signal transduction, cell cycle regulatory, photoperiod and autonomous pathways. Based on the above analysis, a hypothetical model for the regulatory networks of the saffron flowering transition was proposed. This study lays a theoretical basis for the genetic regulation of flowering in C. sativus.
Highlights
Crocus sativus L., commonly called saffron, is a perennial stemless herb belonging to the family Iridaceae, which is widely distributed in Iran, Spain, Greece, Italy and Nepal[1]
In the model plant Arabidopsis thaliana, the flowering transition was found to mainly involve six regulatory pathways: the vernalization, photoperiod, gibberellin, sugar metabolism, autonomous and age pathways[5,6]. These pathways converge to regulate the expression of flowering-related genes, such as FLOWER LOCUS T (FT), CONSTANS (CO), SUPPRESSOR OF OVEREXPRESSION OF CO 1 (SOC1), LEAFY (LFY), APETALA1 (AP1), APETALA2 (AP2) and APETALA3 (AP3), which irreversibly induce the transition from the vegetative meristem to the floral meristem[6,7]
A few studies have reported on saffron EST, transcript data and functions of some genes[21,22,23,24,25,26,27], most of which focused on apocarotenoid biosynthesis, corm sprouting and stigma development, little reported about the regulatory mechanisms of the flowering transition in saffron
Summary
Crocus sativus L., commonly called saffron, is a perennial stemless herb belonging to the family Iridaceae (monocots), which is widely distributed in Iran, Spain, Greece, Italy and Nepal[1]. In the model plant Arabidopsis thaliana, the flowering transition was found to mainly involve six regulatory pathways: the vernalization, photoperiod, gibberellin, sugar metabolism, autonomous and age pathways[5,6] These pathways converge to regulate the expression of flowering-related genes, such as FLOWER LOCUS T (FT), CONSTANS (CO), SUPPRESSOR OF OVEREXPRESSION OF CO 1 (SOC1), LEAFY (LFY), APETALA1 (AP1), APETALA2 (AP2) and APETALA3 (AP3), which irreversibly induce the transition from the vegetative meristem to the floral meristem[6,7]. A few studies have reported on saffron EST, transcript data and functions of some genes[21,22,23,24,25,26,27], most of which focused on apocarotenoid biosynthesis, corm sprouting and stigma development, little reported about the regulatory mechanisms of the flowering transition in saffron. The results of this study lay a foundation for future studies and cultivation efforts, especially for the flowering of Crocus sativus L
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
