QTL mapping and candidate gene analysis of seed vigor-related traits during artificial aging in wheat (Triticum aestivum)

Abstract

High vigor seeds have greater yield potential than those with low vigor; however, long-term storage leads to a decline in this trait. The objective of this study was to identify quantitative trait loci (QTLs) for seed vigor-related traits under artificial aging conditions using a high-density genetic linkage map of wheat (Triticum aestivum) and mine the related candidate genes. A doubled haploid population, derived from a cross between Hanxuan 10 × Lumai 14, was used as the experimental material. Six controlled-environment treatments were set up, i.e. the seeds were aged for 0, 24, 36, 48, 60, and 72 h at a high temperature (48 °C) and under high humidity (relative humidity 100%). Eight traits including seed germination percentage, germination energy, germination index, seedling length, root length, seedling weight, vigor index, and simple vigor index were measured. With the prolongation of artificial aging treatment, these traits showed a continuous downward trend and significant correlations were observed between most of them. A total of 49 additive QTLs for seed vigor-related traits were mapped onto 12 chromosomes (1B, 2D, 3A, 3B, 3D, 4A, 4D, 5A, 5B, 5D, 6D, and 7A); and each one accounted for 6.01–17.18% of the phenotypic variations. Twenty-five pairs of epistatic QTLs were detected on all chromosomes, except for 5D, 6A, and 7D, and each epistasis accounted for 7.35–26.06% of the phenotypic variations. Three additive QTL hot spots were found on chromosomes 5A, 5B, and 5D, respectively. 13 QTLs, QGEe5B, QGIe5B, QSLc5B, QSLd5B, QSLf5B, QRLd5B, QRLe5B, QRLf5B, QVId5B, QVIe5B, QVIf5B, QSVId5B, and QSVIe5B, were located in the marker interval AX-94643729 ~ AX-110529646 on 5B and the physical interval 707,412,449–710,959,479 bp. Genes including TRAESCS5B01G564900, TRAESCS5B01G564200, TRAESCS5B01G562600, TraesCS5B02G562700, TRAESCS5B01G561300, TRAESCS5B01G561400, and TRAESCS5B01G562100, located in this marker interval, were found to be involved in regulating the processes of carbohydrate and lipid metabolism, transcription, and cell division during the germination of aging seeds, thus they were viewed as candidate genes for seed viability-related traits. These findings provide the basis for the seed-based cloning and functional identification of related candidate genes for seed vigor.

Mapping of additive and epistatic QTLs linked to seed longevity in bread wheat (Triticum aestivum L.)

“…For set (ii) seeds, 16.8, 33.4 and 21.4 variations could be explained, respectively, for IG_13, GNA_00 and GNA_02. Previous studies using biparental populations and/or association mapping panels have reported additive QTLs only (Rehman-Arif and , Agacka-Mołdoch et al 2015, Schatzki et al 2013), but information on epistatic QTLs is just starting to be addressed in wheat (Shi et al 2020) and tobacco (Agacka-Mołdoch et al 2021). This report is only the second after Shi et al (2020) to identify epistatic QTLs for seed longevity in bread wheat.…”

“…Previous studies using biparental populations and/or association mapping panels have reported additive QTLs only (Rehman-Arif and , Agacka-Mołdoch et al 2015, Schatzki et al 2013), but information on epistatic QTLs is just starting to be addressed in wheat (Shi et al 2020) and tobacco (Agacka-Mołdoch et al 2021). This report is only the second after Shi et al (2020) to identify epistatic QTLs for seed longevity in bread wheat. A similar level of interactions has recently been detected for Karnal bunt in wheat in an association mapping panel by Singh et al (2020).…”

Quantitative trait loci mapping and candidate gene analysis of stoma-related traits in wheat (Triticum aestivum L.) glumes

“…The genetic map of the DH population was constructed by Jing Ruilian’s team at the Institute of Crop Science, Chinese Academy of Agricultural Sciences ( Li et al, 2019 ). The linkage map is 4,082.4 cM in length and contains 1630 SNP and 224 SSR markers, with 2.2 cM per bin on average ( Shi et al, 2020 ). QTL mapping was performed as previously described in Li et al (2021) using the IciMapping 4.1 software.…”

Genetic Aspects and Molecular Causes of Seed Longevity in Plants—A Review

“…The most recent report addressing seed longevity in wheat from a genetic perspective appeared in 2020 when an analysis of 150 DH lines [ 130 ] was reported after six aging treatments, in which 49 additive QTLs for seed vigor-related traits were mapped onto chromosomes 1B, 2D, 4A, 4D, 6D, and 7A and all group 3 and group 5 chromosomes. In addition, 25 pairs of epistatic QTLs were reported on all chromosomes except chromosomes 5D, 6A, and 7D.…”

“…gCIMapping [ 164 ] might be a useful option to explore seed longevity QTLs in future studies. All of the above-mentioned studies, with the exception of [ 117 , 130 , 153 ], have reported additive QTLs. However, further variation can be detected by exploiting epistatic interactions among loci to explain the genetic determinants of seed longevity.…”