# Short-Term Evolutionary Features and Circadian Clock-Modulated Gene Expression Analysis of Piezo, nanchung, and αTubulin at 67C in a Romanian Population of Drosophila suzukii

## TL;DR

This study explores how genes in an invasive fruit fly species adapt to environmental changes, focusing on their response to circadian rhythm disruptions.

## Contribution

The study introduces a new parameter for evaluating mutation accumulation and shows rapid gene expression changes in response to circadian clock perturbations.

## Key findings

- Genetic changes in non-coding regions of Piezo and nanchung genes are overrepresented in introns.
- Both Piezo and nanchung genes are upregulated in females when circadian rhythms are disrupted.
- Gene expression trends revert when circadian clocks are reset to original timing.

## Abstract

Drosophila suzukii is an invasive fruit fly species that causes major damage to crops. Its success is partly due to its ability to quickly adapt to new environments. In this study, we investigated two genes, Piezo and nanchung (nan), which are also influenced by the circadian rhythm. We analyzed their DNA sequences and gene expression in a Romanian population and compared them to those from the USA and Japan. Our findings show that these genes accumulate genetic changes in non-coding regions and respond quickly to changes in light cycles, with both genes being upregulated. This suggests that D. suzukii uses rapid genetic and physiological adjustments to cope with environmental stress.

Drosophila suzukii is a successful invasive insect species responsible for agricultural losses. The key to its prowess is the ability to swiftly adapt to new environments through various genetic mechanisms, including fast accommodation of mutations and gene expression fine-tuning. Piezo and nanchung (nan) genes are linked to circadian clock-related behaviors and, therefore, are expected to readily respond to stress stimuli. Herein, we compared the DNA sequences of Piezo, nan, and αTubulin at 67C, a highly conserved housekeeping gene, in ICDPP-ams-1, a Romanian local population of D. suzukii, and two well-annotated reference populations from the United States of America and Japan. Our results imply that short-term evolutionary accumulated single nucleotide and indel variants are overrepresented within introns, a propensity evaluated through the mutation accumulation tendency (MAT) original parameter. Piezo and nan gene expression under photoperiodicity changes challenges were assessed in a series of experiments on three groups of individuals from ICDPP-ams-1. We found that both genes are upregulated in females if their customary circadian rhythm is affected, a trend seemingly reverting if, after an initial perturbation, the circadian clock is reset to its initial timing. In conclusion, we found that both highly conserved and adaptability-related genes are rapidly evolving and that Piezo and nan have a fast functional reaction to circadian clock changes by modifying their gene expression profiles.