Presentation Information
[4PL-01]A Natural Transgene Ib-rolB/C as a Stress-Inducible Regulator of Plant Adaptation and Secondary Metabolism
○Yulia Yugay1, Elena Vasyutkina1, Yury Shkryl1 (1. FEDERAL SCIENTIFIC CENTER OF THE EAST ASIA TERRESTRIAL BIODIVERSITY FAR EASTERN BRANCH OF RUSSIAN ACADEMY OF SCIENCES (Russia))
Keywords:
Ib-rolB/C,Ipomoea batatas,CRISPR/Cas9,Plant Adaptation,Secondary Metabolism
Natural transgenes (cT-DNA) derived from Agrobacterium are stably integrated into the genomes of several plant species, including cultivated sweet potato (Ipomoea batatas). Among them, the Ib-rolB/C gene represents a unique example of a horizontally transferred genetic element potentially involved in host adaptation and metabolic regulation. However, its functional role in plant physiology remains insufficiently understood, particularly at the level of regulatory networks.
In this study, we demonstrate that Ib-rolB/C exhibits stress-dependent activation in sweet potato, with strong transcriptional induction under cold, heat, and salt stress conditions, suggesting its involvement in adaptive stress responses.
Functional characterization using heterologous expression in Arabidopsis thaliana revealed a pronounced increase in seed germination under multiple abiotic stress conditions. The most notable effect was observed under heat stress, corresponding to an approximately 13-fold increase in germination efficiency compared to control plants. In addition to enhanced abiotic stress tolerance, transgenic plants also displayed increased resistance to biotic stress: resistance to Pseudomonas syringae increased approximately twofold, while resistance to Botrytis cinerea increased up to fourfold.
Molecular analyses indicate that Ib-rolB/C expression is associated with modulation of stress-related regulatory pathways, including activation of stress-responsive genes and broader reprogramming of cellular responses. The gene also exerts a pronounced effect on secondary metabolism: its expression leads to an approximately twofold increase in flavonoid content. Conversely, CRISPR/Cas9-induced mutations in Ib-rolB/C resulted in reduced accumulation of secondary metabolites both in sweet potato cell cultures and in leaves subjected to transient transformation, supporting a direct role of this gene in metabolic regulation.
Importantly, the observed molecular changes suggest that Ib-rolB/C does not act through a single linear pathway but rather induces systemic reprogramming of cellular homeostasis, integrating stress signaling and metabolic adjustment. This supports the hypothesis that natural transgenes may contribute to host fitness by fine-tuning regulatory networks rather than triggering discrete phenotypic traits.
Overall, our results provide new insights into the functional role of cT-DNA genes in plant genomes and highlight Ib-rolB/C as a modulator of stress-responsive and metabolic pathways, with potential implications for plant biotechnology and adaptive evolution.
Financial support was provided by the Russian Science Foundation, Grant no. 25-74-00041 (Yugay Y.A.).
In this study, we demonstrate that Ib-rolB/C exhibits stress-dependent activation in sweet potato, with strong transcriptional induction under cold, heat, and salt stress conditions, suggesting its involvement in adaptive stress responses.
Functional characterization using heterologous expression in Arabidopsis thaliana revealed a pronounced increase in seed germination under multiple abiotic stress conditions. The most notable effect was observed under heat stress, corresponding to an approximately 13-fold increase in germination efficiency compared to control plants. In addition to enhanced abiotic stress tolerance, transgenic plants also displayed increased resistance to biotic stress: resistance to Pseudomonas syringae increased approximately twofold, while resistance to Botrytis cinerea increased up to fourfold.
Molecular analyses indicate that Ib-rolB/C expression is associated with modulation of stress-related regulatory pathways, including activation of stress-responsive genes and broader reprogramming of cellular responses. The gene also exerts a pronounced effect on secondary metabolism: its expression leads to an approximately twofold increase in flavonoid content. Conversely, CRISPR/Cas9-induced mutations in Ib-rolB/C resulted in reduced accumulation of secondary metabolites both in sweet potato cell cultures and in leaves subjected to transient transformation, supporting a direct role of this gene in metabolic regulation.
Importantly, the observed molecular changes suggest that Ib-rolB/C does not act through a single linear pathway but rather induces systemic reprogramming of cellular homeostasis, integrating stress signaling and metabolic adjustment. This supports the hypothesis that natural transgenes may contribute to host fitness by fine-tuning regulatory networks rather than triggering discrete phenotypic traits.
Overall, our results provide new insights into the functional role of cT-DNA genes in plant genomes and highlight Ib-rolB/C as a modulator of stress-responsive and metabolic pathways, with potential implications for plant biotechnology and adaptive evolution.
Financial support was provided by the Russian Science Foundation, Grant no. 25-74-00041 (Yugay Y.A.).
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