How Sugar and Growth Signals Trigger Flowering in Saffron Plants

Greg Howard
4th May, 2024

How Sugar and Growth Signals Trigger Flowering in Saffron Plants

Image Source: Natural Science News, 2024

Key Findings

  • Researchers discovered genes that control when saffron plants flower, focusing on plants grown in the Himalayas
  • Larger saffron corms (bulbs) were found to have more active genes related to flowering and energy management
  • The study may help improve saffron yields by informing breeding practices for plants with smaller corms
Saffron, the world's most expensive spice, is harvested from the stigmas of the Crocus sativus flower, a plant that has fascinated scientists and farmers alike due to its complex biology and economic value. One of the challenges in saffron cultivation is the plant's inconsistent flowering, which is crucial for stigma production. Not all plants flower equally; smaller corms, the bulb-like storage organs of saffron, often fail to produce flowers, leading to variations in yield. To address this issue, researchers from the CSIR-Institute of Himalayan Bioresource Technology have delved into the genetic mechanisms that control the size-dependent flowering in saffron[1]. The study focused on apical buds, the part of the plant where flowering initiation takes place. By comparing gene expression profiles in buds from small and large corms, the researchers aimed to uncover the genetic factors that determine whether a plant will enter the flowering stage. They used RNA sequencing, a method that reads the genetic information being actively used by cells, to analyze the buds right after they emerged from dormancy. Their findings highlighted the importance of starch and sucrose metabolism—processes involved in the plant's energy management—and the hormonal regulation by Auxin and Abscisic Acid (ABA), which are known to influence plant growth and stress responses. Genes associated with flowering development and circadian rhythm, such as Flowering locus T and Cryptochrome 1, were also found to be more active in the buds from larger corms. Additionally, the study marked the first comprehensive prediction of non-coding RNAs in Crocus sativus, which are molecules that can control when and how genes are turned on or off. The research builds upon previous findings that have begun to unravel the complex genetic and epigenetic landscape of saffron. Earlier studies have shown that saffron is an autotriploid hybrid, which means it has three sets of chromosomes and is derived from one parent species[2]. This genetic makeup contributes to saffron's sterility and clonal propagation. Furthermore, epigenetic variability among different saffron accessions has been linked to phenotypic differences such as flower pigmentation and yield[3]. The transcriptome analysis of saffron tissues has previously identified genes involved in apocarotenoid biosynthesis, which are compounds responsible for saffron's color and medicinal properties[4]. Moreover, the expression of these biosynthetic genes has been found to vary across different developmental stages of the plant[5]. The current study adds to this body of knowledge by pinpointing specific genes and pathways that are crucial for the plant's transition from vegetative growth to flowering. For instance, the identification of Enolase as a key protein in the interaction network suggests its potential as a target for enhancing flowering in saffron. The significance of this research lies not only in its contribution to the basic understanding of saffron biology but also in its practical applications. By identifying the genetic determinants that control flowering based on corm size, the findings offer a potential pathway to improve saffron yields. Farmers and breeders could use this information to select for traits that promote flowering in smaller corms, potentially increasing the overall production of saffron. In conclusion, the study advances our comprehension of the genetic factors influencing size-dependent flowering in Crocus sativus. This work not only integrates with previous research[2][3][4][5] but also opens new avenues for agricultural practices that could stabilize and enhance saffron production, ensuring the livelihood of rural communities that depend on this valuable crop.

GeneticsBiochemPlant Science

References

Main Study

1) Transcriptome analysis of apical meristem enriched bud samples for size dependent flowering commitment in Crocus sativus reveal role of sugar and auxin signalling.

Published 3rd May, 2024

Journal: Molecular biology reports

Issue: Vol 51, Issue 1, May 2024

Related Studies

2) Adding color to a century-old enigma: multi-color chromosome identification unravels the autotriploid nature of saffron (Crocus sativus) as a hybrid of wild Crocus cartwrightianus cytotypes.

https://doi.org/10.1111/nph.15715

3) Epigenetic Variability Among Saffron Crocus (Crocus sativus L.) Accessions Characterized by Different Phenotypes.

https://doi.org/10.3389/fpls.2021.642631

4) De novo transcriptome assembly and comprehensive expression profiling in Crocus sativus to gain insights into apocarotenoid biosynthesis.

https://doi.org/10.1038/srep22456

5) Transcript profiling of carotenoid/apocarotenoid biosynthesis genes during corm development of saffron (Crocus sativus L.).

https://doi.org/10.1007/s00709-018-1296-z


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