# Interaction Between CsATG8f and CsRAP2.12 Modulates Antioxidant Defense and Hypoxia Response During Submergence in Camellia sinensis

## TL;DR

This study shows how two genes in tea plants help them survive flooding by boosting their antioxidant defenses and managing stress.

## Contribution

The novel interaction between CsATG8f and CsRAP2.12 in modulating submergence tolerance in Camellia sinensis is revealed.

## Key findings

- Overexpression of CsATG8f increases autophagosome formation under submergence.
- CsATG8f physically interacts with CsRAP2.12 to regulate hypoxia and antioxidant responses.
- Silenced plants showed increased GABA levels to mitigate submergence stress.

## Abstract

Autophagy is an evolutionarily conserved cellular process that maintains homeostasis by degrading intracellular materials. Numerous studies have investigated the role of autophagy-related genes (ATGs) in plant adaptation to abiotic stresses. In plants, hypoxia (e.g., flooding events, oxygen supply during growth) rapidly activates the autophagy pathway as a protective mechanism for cell survival. Considering the moisture-loving yet waterlogging-sensitive nature of tea plants, this study explored the role of CsATG8f in the tea plant’s response to submergence. We found that overexpression of CsATG8f formed more autophagosomes than controls under submergence. Furthermore, CsATG8f was confirmed to physically interact with CsRAP2.12. Co-overexpression of both genes partially suppressed transcription of hypoxia-response genes while activating the antioxidant system, thereby enhancing tea plants’ resistance to submergence. Consistent with this, the opposite trend was observed in silenced plants, which attempted to mitigate stress damage by increasing GABA levels in vivo. In conclusion, our study reveals the crucial roles of CsATG8f and CsRAP2.12 in tea plant tolerance to submergence and provides new insights into potential regulatory networks governing tea plant adaptation to flooding.