Title : Unveiling the physiological role of betanin breakdown products on stress response mechanisms in germinating Arabidopsis
Abstract:
Seed germination is a pivotal stage in plant development, subject to numerous internal and external factors. While mitochondrial activity, Ros balance, and phytohormonal regulation are well-known, recent studies suggest additional involvement of bioactive compounds, such as those found in agricultural byproducts. This study investigates the potential effects of betanin degradation products (Bdps), derived from discarded pitaya fruit processing waste, on Arabidopsis thaliana germination and early seedling growth, grown under standard, under salt (100 mM Nacl) or osmotic (100 Mm Mannitol) stress condition.
The research encompasses various physiological processes, including Ros signaling, proline accumulation, and phytohormonal regulation. Interestingly, lower concentrations of Bdps (0.02 – 0.20 mg L-1) enhanced seedlings development performances and biomass compared to controls, while higher doses (>1.00 mg L-1) show adverse effects on morphological traits. Moreover, the beneficial concentrations displayed positive effects also on seedlings grown under abiotic stress conditions.
Through assessments using the Mtt assay on both seeds and purified organelle fractions, it is confirmed that the distinct compounds within Bdps neither affect mitochondrial activity nor compromise its integrity. Mechanistically, Bdps modulate Ros signaling by reducing free H2O2 content through enhancing antioxidant activity and regulating the expression of Ros scavenging genes. Furthermore, Bdps influenced proline accumulation, indicating enhanced stress tolerance. The observed rise in proline content correlates with alterations in its metabolism and catabolism, evidenced by changes in gene expression associated with these pathways.
Additionally, Bdps disrupt phytohormone homeostasis, favoring seedling establishment. Particularly, the balance between ABA/ABA-glu, tZea/tZea-rib, and tZea/IAA suggests improved germination performance and seedling development at lower concentration ranges (0.02 – 0.20 mg L-1) and inhibition at higher doses. The increase in GA4 and GA7 content compared to other gibberellins implies involvement of GA13ox, a crucial enzyme in the biosynthetic switch, supported by gene expression evaluations.
In conclusion, the findings of this study underscore the promising role of betanin degradation products as sustainable enhancers of plant growth, particularly in mitigating the impacts of abiotic stress on germination and early seedling development, opening avenues for their application in agriculture.
Audience Takeaway:
- Application in Practice: Agricultural practitioners can apply the insights from this research to improve their approaches to managing crop growth and development, particularly under stress conditions like salt and osmotic stress. By understanding how betanin degradation products influence plant responses, they can make informed decisions about using biostimulants derived from agri-food waste to enhance crop resilience and productivity.
- Job Enhancement: This research equips professionals in the agricultural sector with valuable knowledge that directly impacts their job performance. Understanding the mechanisms underlying plant stress responses enables them to develop more effective strategies for crop management, leading to better outcomes in terms of yield and quality. Furthermore, this research has the potential to inspire the biostimulant industry to develop novel prototypes utilizing agri-food waste enriched with these bioactive compounds.
- Expansion of Research and Teaching: The findings of this study can serve as a valuable resource for other faculty members involved in plant physiology, stress biology, or agricultural science. They can use this research to expand their own investigations or incorporate relevant concepts into their teaching curriculum, enriching both research endeavors and educational programs. Until now, no biostimulant formulation containing BDPs are commercially available.
- Practical Solutions for Designers: For designers and developers in the agricultural industry, this research provides practical solutions for addressing challenges related to plant stress. By elucidating the effects of betanin degradation products on physiological processes, it offers insights that can simplify the development of interventions aimed at improving plant resilience, making designers' jobs more efficient and effective. The current lack on biostimulant research line is the lack in understanding the potential mechanism of action.
- Enhanced Design Accuracy: The research contributes to improving the accuracy of design strategies by providing a deeper understanding of the molecular mechanisms involved in plant stress responses. Armed with this knowledge, designers can develop more precise interventions tailored to specific stress conditions, ultimately leading to better outcomes in terms of crop performance and sustainability.
