# MADS-box gene expression patterns correlate with drought and salt stress responses in Kentucky bluegrass (Poa pratensis L.)

## TL;DR

This study explores how MADS-box genes in Kentucky bluegrass respond to drought and salt stress, identifying potential roles in stress tolerance.

## Contribution

The study identifies 16 MADS-box genes in Kentucky bluegrass and reveals their tissue-specific expression patterns under drought and salt stress.

## Key findings

- Arcadia variety showed greater tolerance to drought and salt stress compared to other varieties.
- 12 out of 16 MADS-box genes exhibited tissue-specific expression under drought stress.
- Six MADS-box genes were significantly upregulated in all tissues under salt stress.

## Abstract

Kentucky bluegrass (Poa pratensis L.) is a perennial cool-season turfgrass commonly utilized in lawns. However, turfgrass quality is affected by abiotic stress. Guided by previous reports demonstrating the critical involvement of MADS-box transcription factors in abiotic stress responses in monocot species such as rice (Oryza sativa) and sheepgrass (Leymis Chinesis), this study specifically focuses on the MADS-box gene family to investigate their potential roles in stress adaptaion mechanisms in Kentucky bluegrass. Although MADS-box genes are well-characterized as regulators of plant growth and development, there is currently limited information on their stress-related functions in this economically important turfgrass species.

This study examined the physiological and molecular responses of three Kentucky bluegrass varieties (K.B.G., Arcadia, and Jenny) to salt and drought stress.

Following initial screening tests, Arcadia was more tolerant to drought and salt stress than Jenny and K.B.G. and, therefore, was selected for further analysis. 16 MADS-box genes from transcriptome analysis have been identified in Kentucky bluegrass. GO enrichment analysis revealed that these genes are primarily involved in transcriptional regulation, including RNA polymerase II-related functions and cis-regulatory region binding. To better understand the function of MADS-box genes under drought and salt stress in Arcadia, the expression levels of 16 MADS-box genes were investigated using quantitative real-time polymerase chain reaction (PCR). Furthermore, 12 of the 16 genes except AGL14, MADS1, MADS26, and MADS33 exhibited tissue-specific expression under drought stress, whereas AGL14, AGL66, MADS16, MADS26, MADS33, and MADS56 were significantly upregulated in all tissues under salt stress. The 2-kb upstream promoter regions of the MADS-box genes were bioinformatically analyzed to identify cis-acting regulatory elements, revealing the presence of multiple cis acting elements associated with development, phytohormone signaling, and stress responses. An in-depth comparative analysis of the varieties indicated that Arcadia exhibits greater resistance to drought and salt stress. The expression patterns of MADS-box genes suggest a potential association with drought and salt stress responses, implying that these genes may play a role in observed stress adaptation.

This study identified 16 MADS-box genes in Kentucky bluegrass and revealed Tissue-specific expression patterns in Arcadia under drought and salt conditions. These candidate genes may contribute to stress tolerance, providing a foundation for further research and potential genetic improvement of Kentucky bluegrass for enhanced resistance to abiotic stresses.