Pan-genome analysis reveals conservation and diversification of the SWEET gene family in wheat
- 1College of Agriculture, Xinyang Agriculture and Forestry University
- 2School of Pharmacy, Xinyang Agriculture and Forestry University
- 3Institute of Biotechnology, Xianghu Laboratory
Abstract
SWEET (Sugars Will Eventually be Exported Transporter) proteins mediate sugar transport and play important roles in plant growth, development, source-sink allocation, and responses to environmental stimuli. However, the conservation and diversification of the SWEET gene family across the wheat pan-genome remain poorly understood. Here, we performed a systematic pan-genome analysis of the SWEET gene family across 19 hexaploid wheat ( Triticum aestivum L.) accessions. A total of 1,594 SWEET genes were identified, with 77–90 members in individual genomes. Gene copies belonging to core, soft-core, dispensable, and private homologous groups accounted for 52.6%, 30.9%, 14.6%, and 1.9%, respectively, based on presence/absence variation (PAV), revealing a predominantly conserved genomic framework accompanied by a smaller accession-variable component. Phylogenetic, motif, chromosomal and synteny analyses further revealed extensive evolutionary and genomic conservation accompanied by localized diversification among family members. Extensive homeologous and inter-accession collinearity was observed, and most pairwise ortholog comparisons exhibited Ka/Ks ratios below 1, supporting predominant purifying selection on conserved SWEET coding sequences. Promoter analysis identified diverse putative cis-regulatory elements related to environmental, hormonal, and developmental regulation, while transcriptome profiling showed heterogeneous tissue- and stress-associated expression patterns among TaSWEET genes. qRT-PCR analysis further suggested distinct temporal responses of selected TaSWEET genes under cold and polyethylene glycol (PEG)-induced osmotic stress. TaSWEET47 overexpression significantly increased grain width, thousand-grain weight, and mature-grain starch content in two independent transgenic lines without significantly affecting grain length. Collectively, these results reveal gene-content, evolutionary, regulatory, and transcriptional diversification within a broadly conserved SWEET family framework.
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BibTeX
@article{yang2026pangenome,
title = {{Pan-genome analysis reveals conservation and diversification of the SWEET gene family in wheat}},
author = {Yanlin Yang and Liuliu Wu and Junyan Sun and Jie Li and Shuhan Liu and Mingming Tang and Zongli Chu and Liping Dong and Shumei Li and Lei Dong},
journal = {Frontiers in Plant Science},
year = {2026},
month = oct,
doi = {10.3389/fpls.2026.1949812},
url = {https://www.frontiersin.org/articles/10.3389/fpls.2026.1949812/full},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Pan-genome analysis reveals conservation and diversification of the SWEET gene family in wheat
AU - Yanlin Yang
AU - Liuliu Wu
AU - Junyan Sun
AU - Jie Li
AU - Shuhan Liu
AU - Mingming Tang
AU - Zongli Chu
AU - Liping Dong
AU - Shumei Li
AU - Lei Dong
PY - 2026
DA - 2026/10/16
JO - Frontiers in Plant Science
DO - 10.3389/fpls.2026.1949812
UR - https://www.frontiersin.org/articles/10.3389/fpls.2026.1949812/full
AB - SWEET (Sugars Will Eventually be Exported Transporter) proteins mediate sugar transport and play important roles in plant growth, development, source-sink allocation, and responses to environmental stimuli. However, the conservation and diversification of the SWEET gene family across the wheat pan-genome remain poorly understood. Here, we performed a systematic pan-genome analysis of the SWEET gene family across 19 hexaploid wheat ( Triticum aestivum L.) accessions. A total of 1,594 SWEET genes were identified, with 77–90 members in individual genomes. Gene copies belonging to core, soft-core, dispensable, and private homologous groups accounted for 52.6%, 30.9%, 14.6%, and 1.9%, respectively, based on presence/absence variation (PAV), revealing a predominantly conserved genomic framework accompanied by a smaller accession-variable component. Phylogenetic, motif, chromosomal and synteny analyses further revealed extensive evolutionary and genomic conservation accompanied by localized diversification among family members. Extensive homeologous and inter-accession collinearity was observed, and most pairwise ortholog comparisons exhibited Ka/Ks ratios below 1, supporting predominant purifying selection on conserved SWEET coding sequences. Promoter analysis identified diverse putative cis-regulatory elements related to environmental, hormonal, and developmental regulation, while transcriptome profiling showed heterogeneous tissue- and stress-associated expression patterns among TaSWEET genes. qRT-PCR analysis further suggested distinct temporal responses of selected TaSWEET genes under cold and polyethylene glycol (PEG)-induced osmotic stress. TaSWEET47 overexpression significantly increased grain width, thousand-grain weight, and mature-grain starch content in two independent transgenic lines without significantly affecting grain length. Collectively, these results reveal gene-content, evolutionary, regulatory, and transcriptional diversification within a broadly conserved SWEET family framework.
SN - 1664-462X
ER -