# Heterologous Expression of the StCML50 Gene Enhances Drought Tolerance in Transgenic Arabidopsis

## TL;DR

This study shows that the StCML50 gene from potato improves drought tolerance in Arabidopsis when overexpressed, helping plants survive under stress.

## Contribution

The study identifies and characterizes the StCML gene family in potato and demonstrates the functional role of StCML50 in enhancing drought tolerance.

## Key findings

- StCML50 overexpression in Arabidopsis improves germination, root elongation, and survival under drought.
- StCML50 enhances antioxidant enzyme activity and reduces malondialdehyde levels in drought conditions.
- Transgenic Arabidopsis with StCML50 shows increased ABA sensitivity and proline accumulation.

## Abstract

Calmodulin-like proteins (CMLs) are key mediators of plant calcium signaling and participate in abiotic stress responses, but their functions in potato remain poorly understood. Here, we systematically identified 62 StCML genes in potato via genome-wide analysis, which were phylogenetically clustered into seven clades and unevenly distributed across 12 chromosomes. Synteny analysis indicated that tandem and segmental duplications drove StCML family expansion, while promoter cis-element analysis suggested their involvement in phytohormone signaling and stress responses. Transcriptomic data showed StCMLs exhibited tissue-specific expression (high in roots, flowers, stamens) and were transcriptionally induced by drought, salt, and abscisic acid (ABA). Heterologous overexpression of StCML50 in Arabidopsis enhanced drought tolerance, as evidenced by improved germination, root elongation, and survival compared to wild-type. Physiologically, StCML50 overexpression increased proline accumulation, boosted antioxidant enzyme (SOD, CAT, POD) activities, and reduced malondialdehyde (MDA) levels under drought. Additionally, transgenic lines showed increased ABA sensitivity. This study provides insights into the potato CML gene family’s evolution and regulatory mechanisms, offering a valuable genetic resource for potato stress tolerance improvement.