# Genome-Wide Identification and Expression Analysis of the CaM Gene Family in Tree Peony (Paeonia ostii) During the Pistil Pollination Process

## TL;DR

This study identifies and analyzes calmodulin genes in tree peony during pollination, revealing their expression patterns and potential roles in the process.

## Contribution

The study provides the first genome-wide identification and expression analysis of the CaM gene family in tree peony during pollination.

## Key findings

- Six CaM family members were identified, located on three chromosomes and one non-chromosome.
- Gene promoters of the CaM family contain numerous hormone and stress response elements.
- CaM gene expression in pistil tissue increases then decreases during pollination, suggesting functional involvement.

## Abstract

Tree peony is an important horticultural plant with both ornamental and oil value. The tree peony genome and databases were used to search for calmodulin family genes to explore their function in the pollination of tree peony. The CaM gene family was identified, and then the basic protein characteristics of the family members, such as gene structure, isoelectric point, molecular weight, subcellular localization, and conserved protein domain, were analyzed. The expression levels of these genes in the pistil tissue of Paeonia ostii ‘Fengdan’ at different developmental stages after pollination were also analyzed. Further, qRT-PCR was used to detect the expression levels of six PsCaMs during the development process of the pistil under bee pollination conditions. The results showed that there were six CaM family members located on three chromosomes and one non-chromosome. There were a large number of hormone response and stress response elements on the gene promoter of this family. During the development of pistil tissue after pollination, CaM family gene expression showed a trend of first increasing and then decreasing, which may be related to its function during pollination. The purpose of this study is to identify the gene characteristics and expression patterns of the CaM family during pollination, and to lay a foundation for the functional study of the CaM family in tree peony pollination.