Quantitative genetic analysis of condensed tannins in oilseed rape meal

Abstract

Condensed tannins (proanthocyanidins, PAs) in the seed meal of oilseed rape can potentially have a negative impact on non-ruminant livestock nutrition, particularly because of their ability to form indigestible, astringent or bitter-tasting complexes with proteins. One option to overcome this problem is the breeding of oilseed rape varieties with reduced condensed tannins in the seed coat. This might be achievable via selection of genotypes with thinner seed coats and consequently reduced condensed tannin accumulation (seed coat structural cell mutants), or alternatively by selection of genotypes with reduced biosynthesis of condensed tannins (flavonoid biosynthesis mutants). Both types of transparent testa (TT) mutants are well-characterised in Arabidopsis; however the genetic basis of the yellow-seed trait in the polyploid genome of rapeseed is still not completely understood. In this study, genetic and chemical analyses of PAs were performed in 166 doubled haploid (DH) rapeseed lines from the segregating Brassica napus doubled haploid population YE2-DH (black seed 9 yellow seed). Using these analyses, the relationship between seed colour and PA fractions in B. napus was investigated with a view to improving the rapeseed meal quality. Proanthocyanidin contents were estimated by vanillin and HPLC assays and the obtained values were used to identify quantitative trait loci. Closely linked molecular markers that were identified during this study for the target traits (seed colour, condensed tannins) can be valuable tools for breeding of new oilseed rape cultivars with reduced levels of antinutritive PA compounds.

Analysis of Flavonoids and Hydroxycinnamic Acid Derivatives in Rapeseeds (Brassica napus L. var. napus) by HPLC-PDA–ESI(−)-MSn/HRMS

“…6 Flavonoids are correlated with the yellow-seeded phenotype. 7 To date, over 200 flavonoids have been identified in Brassica species. 8 Hydroxycinnamic acid derivatives deposited in B. napus provide the bitter taste of rapeseed; conjugation of these derivatives with proteins during the maturation of rapeseed reduces rapeseed nutrition.…”

Dissection of a major QTL for seed colour and fibre content in Brassica napus reveals colocalization with candidate genes for phenylpropanoid biosynthesis and flavonoid deposition

“…, Lipsa et al. ). In crosses between yellow‐seeded and dark‐seeded Chinese oilseed rape, the phenylpropanoid biosynthesis gene CINNAMOYL CO‐A REDUCTASE 1 ( CCR1 ) was revealed as a positional and functional candidate gene for a major QTL on chromosome A9 that explained a considerable proportion of the variation in ADL content (Liu et al.…”

“…Recently, strong associations were reported between seed colour and the content of acid detergent lignin (ADL), the most important antinutritive fibre compound in oilseed rape and canola seed meal (Wittkop et al 2009and Liu et al 2012. A major quantitative trait locus (QTL) with very large effects on seed colour, condensed tannin content and seed acid detergent fibre (ADF) was previously mapped to chromosome A9 in the black-seeded x yellow-seeded doubled haploid population YE2-DH (Badani et al 2006, Snowdon et al 2010, Lipsa et al 2012. In crosses between yellow-seeded and dark-seeded Chinese oilseed rape, the phenylpropanoid biosynthesis gene CINNAMOYL CO-A REDUCTASE 1 (CCR1) was revealed as a positional and functional candidate gene for a major QTL on chromosome A9 that explained a considerable proportion of the variation in ADL content (Liu et al 2012).…”

Current Research Developments on the Processing and Improvement of the Nutritional Quality of Rapeseed (Brassica napus L.)

“…While the proportion of condensed tannins in the cotyledons of rape seeds is relatively low (about 0.1–0.5% of dry weight), condensed tannins in dark‐seeded oilseeds rape could comprise up to 6% of the seed coat. This means that they contribute substantially to meal of rapeseed, with a total concentration level up to 800 mg/100 g after oil extraction . In Naczk et al studies the total content of tannins in rapeseed hulls was in the range from 1913 to 6213 mg/100 g of oil‐free hulls.…”

“…Plant tannins represent a particular group of high molecular weight phenolic compounds that have the ability to complex heavily with proteins, starch, cellulose, and minerals. Chemically, three groups of tannins are observed: phlorotannins, hydrolysable, and condensed tannins …”