# Long-Term Phytaspase Responses in Nicotiana benthamiana: Sustained Activation by Mechanical Wounding, but Not by Drought, Heat, Cold, or Salinity Stress

## TL;DR

This study shows that phytaspase activity in Nicotiana benthamiana is sustained after mechanical wounding but not after drought, heat, or salinity stress.

## Contribution

The study reveals the specific role of phytaspase in long-term mechanical wounding responses, not in other abiotic stresses.

## Key findings

- Phytaspase activity and gene expression increased with mechanical wounding severity and recurrence.
- No significant phytaspase activity change was observed under drought, salinity, or heat stress.
- Phytaspase is linked to long-term mechanical injury responses in Nicotiana benthamiana.

## Abstract

Plant subtilases, as hydrolytic enzymes, contribute to certain plant stress response pathways by cleaving precursor proteins into active peptides or through other less well-characterized mechanisms. Phytaspases represent a specific subgroup of subtilases, and their participation in rapid stress responses, particularly to herbivory attacks and drought, is already well established, in contrast to their poorly understood role in long-term responses. This study investigated the involvement of phytaspase NbSBT1.9-2 in the long-term stress responses of Nicotiana benthamiana. Plants were subjected to either mild to severe mechanical wounding or drought stress, followed by the detection of phytaspase activity and gene expression in the leaf tissue. The results revealed a distinct involvement of phytaspase in the wounding response, showing increased activity and upregulated expression correlated with the extent and recurrence of wounding. In contrast, no significant change in phytaspase activity was observed in the leaves under drought, alongside salinity and heat stress conditions. Consequently, phytaspase association with the long-term response to mechanical injury was demonstrated using N. benthamiana as a model organism.