Characterization of the quantitative trait locus OilA1 for oil content in Brassica napus

Abstract

Increasing seed oil content has become one of the most important breeding criteria in rapeseed (Brassica napus). However, oil content is a complex quantitative trait. QTL mapping in a double haploid population (SG population) emerging from a cross between a German (Sollux) and Chinese (Gaoyou) cultivars revealed one QTL for oil content on linkage group A1 (OilA1), which was mapped to a 17 cM genetic interval. To further validate and characterize the OilA1, we constructed a high-resolution map using B. rapa sequence resources and developed a set of near-isogenic lines (NILs) by employing a DH line SG-DH267 as donor and Chinese parent Gaoyou as recurrent background. The results showed highly conserved synteny order between B. rapa and B. napus within the linkage group A1 and revealed a possible centromere region between two markers ZAASA1-38 and NTP3 (2.5 cM). OilA1 was firstly validated by 250 BC5F2 plants and was confirmed in a 10.6 cM interval between the markers ZAASA1-47 and ZAASA1-77. Further substitution mapping was conducted by using two generations of QTL-NILs, 283 lines from eight BC5F3:4 families and 428 plants from six BC5F4 sub-NILs and thus narrowed the OilA1 interval to 6.9 cM and 4.3 cM (1.4 Mb), respectively. Field investigations with two replications using homozygous BC5F3:4 sister sub-NILs indicated that NILs, which carry a Sollux chromosome segment across the target region showed significant higher oil content (1.26 %, p < 0.001) than their sister NILs containing Gaoyou chromosome. The OilA1 locus is of particular interest for breeding purpose in China because 80 % of Chinese cultivars do not carry this desirable allele.

Identification of QTL for seed coat colour and oil content inBrassica napusby association mapping using SSR markers

“…associated with oil content, distributed on A1 and A8 in the RIL population (Yan et al 2009b), and were regarded as the same loci for oil content (Delourme et al 2006;Qiu et al 2006;Zhao et al 2012;Chen et al 2013;Jiang et al 2014). Hence, the association mapping results were in good agreement with published QTL detected in other B. napus populations.…”

“…These works showed that seed oil content is quantitative in nature and controlled by multiple genes termed quantitative trait loci (QTL), found in almost all the 19 linkage groups, and the trait is affected by environment (G )E) (Burns et al 2003;Zhao et al 2005Zhao et al , 2006Delourme et al 2006;Qiu et al 2006;Amar et al 2008;Yan et al 2009b;Chen et al 2010Chen et al , 2013Sun et al 2012). Moreover, a QTL associated with oil content located in the linkage group 1 (A1) near the public SSR markers BRAS041 or BRAS078 of B. napus has been frequently reported (Zhao et al 2005(Zhao et al , 2012Delourme et al 2006;Qiu et al 2006;Chen et al 2013;Jiang et al 2014), and we also found CB10369 and BRAS041 were mapped to the adjacent regions. Similarly, it should also be mentioned that one QTL for seed oil content was mapped to linkage group A8 in different crosses (Burns et al 2003;Delourme et al 2006;Qiu et al 2006;Amar et al 2008).…”

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.…”

Identification of QTLs Associated with Oil Content in a High-Oil Brassica napus Cultivar and Construction of a High-Density Consensus Map for QTLs Comparison in B. napus

“…detected 12 QTLs in three trials using Z5 (‘zy036’ב51070’) DH population with 92 lines whose parents had approximately 10% difference in their seed oil contents [25]. Zhao et al validated and characterized that the QTL OilA1 could influence oil content in rapeseed within the linkage group A1 using a set of near-isogenic lines (NILs) [26]. Each member of the mapping population might carry different alleles for oil content and represents its own genetic background.…”