Abstract
Cytokinins (CKs) are a family of evolutionarily conserved growth regulating hormones. While CKs are well-characterized in plant systems, these N6-substituted adenine derivatives are found in a variety of organisms beyond plants, including bacteria, fungi, mammals, and the social amoeba, Dictyostelium discoideum. Within Dictyostelium, CKs have only been studied in the late developmental stages of the life cycle, where they promote spore encapsulation and dormancy. In this study, we used ultra high-performance liquid chromatography-positive electrospray ionization-high resolution tandem mass spectrometry (UHPLC-(ESI+)-HRMS/MS) to profile CKs during the Dictyostelium life cycle: growth, aggregation, mound, slug, fruiting body, and germination. Comprehensive profiling revealed that Dictyostelium produces 6 CK forms (cis-Zeatin (cZ), discadenine (DA), N6-isopentenyladenine (iP), N6-isopentenyladenine-9-riboside (iPR), N6-isopentenyladenine-9-riboside-5′ phosphate (iPRP), and 2-methylthio-N6-isopentenyladenine (2MeSiP)) in varying abundance across the sampled life cycle stages, thus laying the foundation for the CK biosynthesis pathway to be defined in this organism. Interestingly, iP-type CKs were the most dominant CK analytes detected during growth and aggregation. Exogenous treatment of AX3 cells with various CK types revealed that iP was the only CK to promote the proliferation of cells in culture. In support of previous studies, metabolomics data revealed that DA is one of the most significantly upregulated small molecules during Dictyostelium development, and our data indicates that total CK levels are highest during germination. While much remains to be explored in Dictyostelium, this research offers new insight into the nature of CK biosynthesis, secretion, and function during Dictyostelium growth, development, and spore germination.
Highlights
Dictyostelium discoideum is one of the most well-known representatives of the Amoebozoa phylum [1].Owing to its unique life cycle, this social amoeba can exist both as a single-cellular and multicellular organism
Through comprehensive profiling of 30 naturally occurring CKs, this study reveals that Dictyostelium produces and secretes 6 CK forms in varying abundance throughout the life cycle, giving insight into CK biosynthesis among social amoebae
Our CK profiling analysis revealed that Dictyostelium synthesizes 6 CK forms in varying concentrations throughout the different life cycle stages: cZ, DA, iP, N6 -isopentenyladenosine, (2MeSiP) (Figure 1A)
Summary
Dictyostelium discoideum is one of the most well-known representatives of the Amoebozoa phylum [1].Owing to its unique life cycle, this social amoeba can exist both as a single-cellular and multicellular organism. Dictyostelium amoebae feed upon bacteria and decaying leaf litter in the forest soil. CAMP is secreted as a chemical messenger in a pulsatile manner from the population of starved amoebae and acts as a chemoattractant causing the cells to migrate towards a central location [3,4]. Light and temperature guide the migration of the slug towards the top layer of the forest soil, where the fruiting body forms. This final structure consists of a slender tube-like stalk that suspends the spores above the surface for future germination and largely depends on cytokinins (CKs), which are signalling molecules that initiate spore formation and maintain spore dormancy [6,7,8]
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.
