Plants have long fascinated scientists for their remarkable ability to regrow from small cuttings. A leaf placed in soil can sprout roots and eventually develop into a whole new plant. But how do plants survive the stress of injury and still manage to regenerate?
A new study from the Indian Institute of Science Education and Research (IISER) Pune offers fresh insights into this question. Published in the journal Proceedings of the National Academy of Sciences (PNAS), USA, the research led by Prof Kalika Prasad reveals how plants use a cellular clean-up mechanism called autophagy to heal and regenerate after injury.
“Plants can reproduce asexually through vegetative propagation, a process known for centuries. But the underlying mechanism that allows plants to withstand the stress of being cut and still regenerate remained unclear,” Prof Prasad said, describing the motivation behind the study.
The team found that when a plant is wounded, such as when a leaf, stem, or root is cut, the cells experience a sudden rise in reactive oxygen species (ROS). While high levels of ROS can damage cells, the study shows that plants have evolved a precise system to manage this stress.
Central to this process is autophagy, a biological mechanism found in almost all living organisms that removes damaged cellular components and helps maintain cellular balance. The researchers discovered that autophagy activation is essential for root regeneration from leaf cut ends because it reduces ROS levels to an optimal range, allowing regeneration to proceed.
The study identified two specific autophagy-related genes, ATG8F and ATG8H, that play a crucial role in root regeneration. Further investigation showed that these genes are regulated by plant-specific proteins known as PLETHORA (PLT) proteins. In particular, PLT7 regulates ATG8F, while PLT3 controls ATG8H.
This revealed a previously unknown regulatory system in plants where PLETHORA proteins guide the autophagy process to control ROS levels during regeneration.
Once cellular stress is brought under control through autophagy, stem cell regulators accumulate at the wound site, enabling the plant to form new roots and organs.
“It is interesting to see that in both plants and animals, ROS act as early wound signals that activate autophagy to restore balance and support tissue regrowth. However, plants add their own unique twist by using PLETHORA proteins to guide this process for successful regeneration precisely,” Prof Prasad explained.
The research was conducted at IISER Pune with support from national funding agencies, including the Department of Biotechnology, Government of India, and the Anusandhan National Research Foundation. The work was led by PhD student Akansha Ganguly, along with undergraduate students Aabha Humnabadkar and Komal Gautam. Collaborators from the Netherlands, China, and Germany contributed by providing research reagents.
