Identification of quantitative trait loci associated with oil content and development of near isogenic lines for stableqOC-A10inBrasscia napusL.

Abstract

Seed oil content is a key seed quality trait determining the economic value of rapeseed (Brassica napus L.). However, it is a complex quantitative trait controlled by multiple genes. To this point, its genetic mechanism in rapeseed remains to be revealed. In the present study, we separately identified the quantitative trait loci (QTL) controlling seed oil content of B. napus using three generations of recombinant inbred line (RIL) populations (F 4:5 , F 5:6 , and F 6:7 ) derived from a cross of two contrasting parents (M201, a high-oil parent, and M202, a low-oil parent) in four trials. The results indicated that the additive effects may be the primary factors contributing to the variation in seed oil content in B. napus. A total of 15 QTL for seed oil content were mapped. Two of them, namely qOC-A9-3 and qOC-A10, were consistently detected across two and all four environments, respectively. Meanwhile, qOC-A10 showed a large effect on phenotypic variation in seed oil content. The stability and significance of qOC-A10 was also validated in the near isogenic lines (NILs-qOC-A10) developed from the RIL population (F 4:5 ) using marker-assisted selection. The qOC-A10 is of particular interest for further fine mapping and map-based cloning.Key words: Brassica napus L., quantitative trait loci, oil content, additive genetic effect, SSR marker.Résumé : La teneur en huile de la graine est un caractère crucial de la qualité qui détermine la valeur économique du colza (Brassica napus L.). Il s'agit néanmoins d'un caractère quantitatif complexe, car de multiples gènes le régulent. Jusqu'à présent, ce mécanisme génétique du colza nous échappait. Dans la présente étude, les auteurs ont identifié séparément les locus quantitatifs (QTL) qui commandent la concentration d'huile dans la graine de B. napus grâce à trois populations (F 4:5 , F 5:6 , et F 6:7 ) de lignées autogames recombinantes (RIL) issues d'un croisement entre deux parents contrastants (à savoir, M201, une variété riche en huile, et M202, une variété pauvre en huile), au terme de quatre essais. Les résultats indiquent que des effets additifs pourraient principalement être à l'origine de la teneur en huile variable des graines de B. napus. Ils ont cartographié 15 QTL régulant la concentration d'huile dans la graine. Deux, en l'occurrence qOC-A9-3 et qOC-A10, ont constamment été détectés respectivement dans deux et les quatre situations. Parallèlement, qOC-A10 a une profonde incidence sur la variation phénotypique de la teneur en huile. La stabilité et l'importance de qOC-A10 ont également été validées par les lignées quasi isogéniques (NILs-qOC-A10) obtenues de la population (F 4:5 ) des RIL après sélection avec des marqueurs. Le locus qOC-A10 revêt un intérêt particulier en vue d'une cartographie plus précise du génome et du clonage à partir de la carte génétique. [Traduit par la Rédaction] Mots-clés : Brassica napus L., locus quantitatif, teneur en huile, effet additif des gènes, marqueur SSR.

Synteny analysis of genes and distribution of loci controlling oil content and fatty acid profile based on QTL alignment map in Brassica napus

“…It is a very good approach for detecting hot spot genomic regions associated with the traits, but not always accurate for validating exact QTL. These nine populations were produced from hybridization of different varieties of B. napus : DY is a hybrid of European and Korean [ 37 ], SG and TN are hybrids of European and Chinese [ 35 , 67 ], Z5, KN and M201XM202 are Chinese [ 42 , 48 , 68 ], SO is European [ 69 ] and PT is Canadian [ 70 ]. Genesis of variety within a species initiates in natural selection which enables species to settle into specific environmental pressures.…”

“…OC-QTLs and FA-QTLs from nine previously reported populations were aligned into one map for comparison: DY (‘Darmor-bzh’ × ‘Yudal’) [ 37 ], RNSL (‘Rapid’ × ‘NSL96/25’) [ 37 ], Z5 (‘zy036’ × ‘51,070’) [ 39 ], SG (‘Sollux’ × ‘Gaoyou’) [ 40 , 41 ], KN (‘KenC-8’ × ‘N53–2’) [ 42 , 43 ], TN (‘Tapidor’ × ‘Ningyou7’) [ 44 , 45 ], SO (Sansibar × Oase) [ 46 ], PT (Polo × Topas) [ 47 ] and M201 × M202 [ 48 ]. The QTLs were projected onto the physical map of the reference genome “ Darmor-bzh” and the position of related flanking markers were identified by using of E-PCR [ 83 , 84 ].…”

Genetic dissection of seed oil and protein content and identification of networks associated with oil content in Brassica napus

“…The genomic regions of QTLs from other populations, DY (‘Darmor-bzh’ × ‘Yudal’, RNSL (‘Rapid’ × ‘NSL96/25’)75, Z5 (‘zy036’ × ‘51,070’)76, SG (‘Sollux’ × ‘Gaoyou’)77, TN (‘Tapidor’ × ‘Ningyou7’)42, SO (‘Sansibar’ × ‘Oase’)78, PT (‘Polo’ × ‘Topas’)79, and M201 × M20280, were obtained via electronic PCR (e-PCR)81, which was performed with the primer sequences of the molecular markers flanking the QTL confidence intervals using the genomic sequences of ‘Darmor- bzh ’ as templates.…”

Genetic Variability in a Population of Oilseed Rape DH Lines Developed from F1 Hybrids of a Cross between Black- and Yellow-Seeded DH Lines. II. Seed Quality

“…The positive significant correlation between dark seed colour and seed fat content did not confirm many reports of increased fat content in yellow-seeded oilseed rapes [7,25,40]. Many reports also indicate the additive effect of genes as the main factor controlling the fat content in seeds [39,[41][42][43][44]. According to Zhao et al [45], crossing appropriately selected varieties and the derivation of DH lines allows the breeding of genotypes with a higher fat content than the parents by combining the positive alleles of genes derived from different gene pools.…”