Abstract
In the present work, non-targeted metabolomics was used to investigate the seed response to kinetin, a phytohormone with potential roles in seed germination, still poorly explored. The aim of this study was to elucidate the metabolic signatures of germination triggered by kinetin and explore changes in metabolome to identify novel vigor/stress hallmarks in Medicago truncatula. Exposure to 0.5 mM kinetin accelerated seed germination but impaired seedling growth. Metabolite composition was investigated in seeds imbibed with water or with 0.5 mM kinetin collected at 2 h and 8 h of imbibition, and at the radicle protrusion stage. According to Principal Component Analysis, inositol pentakisphosphate, agmatine, digalactosylglycerol, inositol hexakisphosphate, and oleoylcholine were the metabolites that mostly contributed to the separation between 2 h, 8 h and radicle protrusion stage, irrespective of the treatment applied. Overall, only 27 metabolites showed significant changes in mean relative contents triggered by kinetin, exclusively at the radicle protrusion stage. The observed metabolite depletion might associate with faster germination or regarded as a stress signature. Results from alkaline comet assay, highlighting the occurrence of DNA damage at this stage of germination, are consistent with the hypothesis that prolonged exposure to kinetin induces stress conditions leading to genotoxic injury.
Highlights
At the onset of germination, the transition from a dry quiescent state to a fully hydrated state is associated with extensive metabolic changes[1,2]
The to reach 50% germination (T50) parameter was significantly reduced when comparing the 0.5 mM and 0.75 mM kinetin doses with control samples imbibed with water (W) (Supplementary Table 1)
Inhibition of root growth was observed in four-day-old M. truncatula seedlings developed in presence of kinetin (Supplementary Table 1 and Supplementary Fig. 2)
Summary
At the onset of germination, the transition from a dry quiescent state to a fully hydrated state is associated with extensive metabolic changes[1,2] This is a crucial phase for seed viability and vigor since water up-take causes increased ROS (reactive oxygen species)-mediated oxidative injury[3,4], and exacerbates genotoxic damage[5,6]. Reduced field performance generally results from the variability in number and speed of seedling emergence, reflecting poor seed vigor[27] These unfavorable features can be mitigated by means of tailored priming protocols that require, a deeper technical knowedge tightly linked to a better comprehension of the molecular aspects of the pre-germinative metabolism[28]. Due to the high synteny of this model species with other legumes, the results of this investigation can impact research on seed biology in other economically relevant legume crops, such as pulses
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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.
