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bioRxiv · 10.1101/2025.08.27.672299

Deciphering the role of autophagy under Cd toxicity in Arabidopsis thaliana

Collado-Arenal, A. M.·Perez-Gordillo, F. L.·Espinosa, J.·Moreno-Diaz, R.·Shabala, S.·Romero-Puertas, M. C.·Sandalio, L. M.
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Abstract

Cadmium (Cd) is a toxic pollutant in soil and water affecting plants, animals, and humans. Autophagy, a cellular recycling process, is crucial for different biotic and abiotic plant stress responses. This study explores the autophagy role in Arabidopsis under Cd stress, using wild-type, autophagy-deficient mutants (atg5, and atg7) and overexpressing lines (35S:ATG5, 35S:ATG7). Cd exposure induced autophagy, as evidenced by ATG8a and ATG8a-PE accumulation, GFP-ATG8a fluorescence, and upregulation of ATG genes and proteins. Responses differed between Col-0 and Ws backgrounds, with Ws showing higher Cd tolerance. atg5 mutants were more sensitive to Cd, indicating the autophagy protective role, whereas ATG5/ATG7 overexpression did not significantly enhance Cd tolerance. Although oxidative stress may activate autophagy, ATG5/ATG7 overexpression did not significantly change the oxidative stress response. Notably, atg5 mutants displayed marked disruptions in metal/ion homeostasis under control and Cd conditions, reinforcing autophagys role inion homeostasis. In contrast, atg7 showed no significant differences from its WT (Ws), suggesting genotype-specific effects. Transcriptional analysis of metal transporters and ion flux analyses indicates that autophagy can regulate metal/ion accumulation through transcriptional control and post-translational modifications (e.g., ROS) with a differential response being observed between Ws and Col-0 plants.

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Collado-Arenal, A. M., Perez-Gordillo, F. L., Espinosa, J., Moreno-Diaz, R., Shabala, S., Romero-Puertas, M. C., Sandalio, L. M.. 2025-08-31. Deciphering the role of autophagy under Cd toxicity in Arabidopsis thaliana. https://doi.org/10.1101/2025.08.27.672299

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