Identification of QTLs and candidate genes associated with seed germination capacity under heat stress in watermelon
Abstract
BackgroundHeat stress (HS) severely inhibits seed germination of direct-seeded crops such as watermelon. However, the genetic basis governing germination capacity under HS remains largely unclear.MethodsAn F2 population consisting of 132 individuals was developed from a cross between the heat-tolerant inbred line 8R098 (high germination under HS) and the heat-sensitive line 8R122 (low germination under HS). SNP-trait association analysis and linkage mapping were employed to dissect the genetic basis of seed germination capacity under HS. Germination-stage RNA-seq of high- and low-germination accessions under HS was performed to screen the DEGs.ResultsHeat tolerance for seed germination segregated at a high-to-low ratio of 1: 3, indicating a nearly recessive genetic nature. A major QTL for HS germination tolerance was fine-mapped to the interval of 29.05~33.41 Mb on chromosome 10, harboring 472 annotated genes. RNA-seq identified 1,519 HS-responsive DEGs enriched in plant hormone signal transduction and metabolic pathways. A total of 101 putative functional non-synonymous SNPs (nsSNPs) were found in 76 protein-coding genes within this QTL region. Integrative analysis of DEGs and nsSNP-containing genes, followed by filtering genes with inconsistent expression trends, retained four candidate genes with allelic variations, namely Cla97C10G205480, Cla97C10G205850, Cla97C10G204760, and Cla97C10G203920.ConclusionOur findings reveal candidate genes regulating thermotolerance during watermelon seed germination and provide useful genetic resources for breeding watermelon varieties with improved heat tolerance at the germination stage.
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BibTeX
@article{song2026identification,
title = {{Identification of QTLs and candidate genes associated with seed germination capacity under heat stress in watermelon}},
author = {Jianfei Song and Yiying Zhang and Nannan Li and Jianli Shang and Dan Zhou and Shuangwu Ma and Na Li},
journal = {Frontiers in Plant Science},
year = {2026},
month = oct,
doi = {10.3389/fpls.2026.1932864},
url = {https://www.frontiersin.org/articles/10.3389/fpls.2026.1932864},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Identification of QTLs and candidate genes associated with seed germination capacity under heat stress in watermelon
AU - Jianfei Song
AU - Yiying Zhang
AU - Nannan Li
AU - Jianli Shang
AU - Dan Zhou
AU - Shuangwu Ma
AU - Na Li
PY - 2026
DA - 2026/10/30
JO - Frontiers in Plant Science
DO - 10.3389/fpls.2026.1932864
UR - https://www.frontiersin.org/articles/10.3389/fpls.2026.1932864
AB - BackgroundHeat stress (HS) severely inhibits seed germination of direct-seeded crops such as watermelon. However, the genetic basis governing germination capacity under HS remains largely unclear.MethodsAn F2 population consisting of 132 individuals was developed from a cross between the heat-tolerant inbred line 8R098 (high germination under HS) and the heat-sensitive line 8R122 (low germination under HS). SNP-trait association analysis and linkage mapping were employed to dissect the genetic basis of seed germination capacity under HS. Germination-stage RNA-seq of high- and low-germination accessions under HS was performed to screen the DEGs.ResultsHeat tolerance for seed germination segregated at a high-to-low ratio of 1: 3, indicating a nearly recessive genetic nature. A major QTL for HS germination tolerance was fine-mapped to the interval of 29.05~33.41 Mb on chromosome 10, harboring 472 annotated genes. RNA-seq identified 1,519 HS-responsive DEGs enriched in plant hormone signal transduction and metabolic pathways. A total of 101 putative functional non-synonymous SNPs (nsSNPs) were found in 76 protein-coding genes within this QTL region. Integrative analysis of DEGs and nsSNP-containing genes, followed by filtering genes with inconsistent expression trends, retained four candidate genes with allelic variations, namely Cla97C10G205480, Cla97C10G205850, Cla97C10G204760, and Cla97C10G203920.ConclusionOur findings reveal candidate genes regulating thermotolerance during watermelon seed germination and provide useful genetic resources for breeding watermelon varieties with improved heat tolerance at the germination stage.
SN - 1664-462X
ER -