# Leaf transcriptome differences between diploid and tetraploid bahiagrass

## TL;DR

This study compares gene expression in diploid and tetraploid bahiagrass to understand how genome duplication affects traits like stress tolerance and vigor.

## Contribution

The study provides a comprehensive transcriptomic catalog and identifies key regulators and breeding targets in polyploid bahiagrass.

## Key findings

- Polyploid bahiagrass shows distinct transcriptomic profiles affecting development, redox homeostasis, and photosynthesis.
- Differentially expressed genes include transcription factors and hormone-related genes important for breeding.
- Co-expression network analysis identified 532 master regulators with non-random genomic distribution.

## Abstract

Polyploid individuals of the subtropical forage grass Paspalum notatum Flüggé (bahiagrass) exhibit distinct phenotypes, including apomixis, enhanced vigor, gigas effects, and increased stress tolerance. While apomixis‐based breeding programs supported by molecular tools have improved agronomic traits such as growth habit, forage dry matter, and lipid profile, a genome‐wide understanding of ploidy‐induced transcriptomic changes is still lacking. In this study, we aimed to generate a comprehensive reference catalog of transcripts differentially expressed in the leaves of diploid and tetraploid individuals, characterize genome responses to polyploidy, and identify candidate genes for breeding. Our results reveal distinct transcriptomic profiles in polyploids, with significant impacts on development, redox homeostasis, and photosynthesis—patterns consistent with those observed in other species. Gene ontology enrichment analyses highlighted key categories related to stress responses and signaling pathways. We also identified critical breeding targets, including transcription factors and hormone‐related genes. Co‐expression network analysis uncovered 532 master regulators affected by genome doubling, with non‐random distribution across the genome and hotspot clustering in specific chromosomes. Overall, our findings provide novel insights into the molecular consequences of polyploidy in P. notatum, offering a valuable resource for molecular breeding programs aimed at improving stress tolerance, vigor, and other desirable traits.

Polyploid bahiagrass plants show enhanced adaptation, including stress tolerance and increased vigor.Leaf transcriptomes were assembled for sexual diploid and tetraploid bahiagrass plants.Transcriptomes reveal how sexual diploid and tetraploid bahiagrass differ at the gene expression level.Differentially expressed genes include key breeding targets, such as transcription factors and hormone‐related genes.This study provides molecular resources to improve bahiagrass stress tolerance, vigor, and other agronomic traits.

Polyploid bahiagrass plants show enhanced adaptation, including stress tolerance and increased vigor.

Leaf transcriptomes were assembled for sexual diploid and tetraploid bahiagrass plants.

Transcriptomes reveal how sexual diploid and tetraploid bahiagrass differ at the gene expression level.

Differentially expressed genes include key breeding targets, such as transcription factors and hormone‐related genes.

This study provides molecular resources to improve bahiagrass stress tolerance, vigor, and other agronomic traits.

Bahiagrass plants have more than two sets of chromosomes. These plants, known as polyploids, often grow more vigorously and cope with stress more effectively due to changes in gene expression. In this study, we compared the leaf gene expression of plants with two and four sets of chromosomes to understand how genome duplication affects biological functions. We found that many genes related to growth, stress response, and cell signaling were more active in polyploids, and identified 2370 important gene regulators grouped in specific regions of the genome. These genes may help explain how polyploid plants adapt and show enhanced traits. Our findings offer useful information for breeding programs that traditionally combine apomictic and sexual seed reproduction, and could lead to new molecular tools to support bahiagrass improvement.