Molecular breeding for introgression of fatty acid desaturase mutant alleles ( ahFAD2A and ahFAD2B ) enhances oil quality in high and low oil containing peanut genotypes

Abstract

High oleate peanuts have two marketable benefits, health benefits to consumers and extended shelf life of peanut products. Two mutant alleles present on linkage group a09 (ahFAD2A) and b09 (ahFAD2B) control composition of three major fatty acids, oleic, linoleic and palmitic acids which together determine peanut oil quality. In conventional breeding, selection for fatty acid composition is delayed to advanced generations. However by using DNA markers, breeders can reject large number of plants in early generations and therefore can optimize time and resources. Here, two approaches of molecular breeding namely marker-assisted backcrossing (MABC) and marker-assisted selection (MAS) were employed to transfer two FAD2 mutant alleles from SunOleic 95R into the genetic background of ICGV 06110, ICGV 06142 and ICGV 06420. In summary, 82 MABC and 387 MAS derived introgression lines (ILs) were developed using DNA markers with elevated oleic acid varying from 62 to 83%. Oleic acid increased by 0.5-1.1 folds, with concomitant reduction of linoleic acid by 0.4-1.0 folds and palmitic acid by 0.1-0.6 folds among ILs compared to recurrent parents. Finally, high oleate ILs, 27 with high oil (53-58%), and 28 ILs with low oil content (42-50%) were selected that may be released for cultivation upon further evaluation.

Composition and variation of fatty acids among groundnut cultivars in Uganda

“…Nonetheless, the major fatty acids consistently observed in this study were oleic, linoleic and palmitic fatty acids constituting ~90% of the fatty acids, irrespective of the genotype. This finding was also reported by Singhkam et al (2012);Hassan and Ahmed (2012);Janila et al (2015) and Wang et al (2015), irrespective of the method of fatty acid profiling /analysis. The significant variation in both major (oleic, linoleic and palmitic acids) and minor (arachidic, behenic, palmitoleic and gadoleic) fatty acids composition among the groundnut genotypes in this study indicates genetic differences among the genotypes for the different fatty acids (Hassan and Ahmed, 2012) which is crucial for fatty acid improvement.…”

Accelerating genetic gains in legumes for the development of prosperous smallholder agriculture: integrating genomics, phenotyping, systems modelling and agronomy

“…The legume community has been successful in developing several molecular breeding products despite the late arrival of genomic resources and trait-associated markers (Varshney et al, 2013a,b;Pandey et al, 2016;Varshney, 2016). Some key examples include resistance to Fusarium wilt and ascochyta blight (Varshney et al, 2013b) and improved drought tolerance (Varshney et al, 2013a) in chickpea; resistance to nematode and high oleic acid (Chu et al, 2011), resistance to leaf rust , and resistance to high oleic acid (Janila et al, 2016) in groundnut; resistance to rust disease (Khanh et al, 2013), soybean mosaic virus (Saghai-Maroof et al, 2008;Shi et al, 2009;Parhe et al, 2017), and low phytate (Landau-Ellis and Pantalone, 2009) in soybean; Striga resistance and seed size in cowpea (Lucas et al, 2015; see Boukar et al, 2016); pyramid genes for resistance to ascochyta blight and anthracnose in lentil (Taran et al, 2003); powdery mildew resistance (Ghafoor and McPhee 2012), lodging resistance (Zhang et al, 2006), frost tolerance (see Tayeh et al, 2015b), and Aphanomyces root rot resistance (Lavaud et al, 2015) in pea; and resistance to common bacterial blight disease (Miklas et al, 2000(Miklas et al, , 2006Mutlu et al, 2005;O'Boyle and Kelly, 2007), rust and viruses (Stavely, 2000), rust, anthracnose, and angular leaf spot (Oliveira et al, 2008), rust (Feleiro et al, 2001), and anthracnose (Alzate-Marin et al, 1999) in common bean. Several of these improved lines have either been released or are in the release pipeline in different countries.…”

Insights into the Indian Peanut Genotypes for ahFAD2 Gene Polymorphism Regulating Its Oleic and Linoleic Acid Fluxes

“…Further, a saturated fatty acid (SFA), palmitic acid contributing to about 10%, whereas, rest 10% is constituted of up to 9 other fatty acids (Janila et al, 2016). Thus, the flavor, shelf-life, and nutritional quality of peanut seeds and its products are reliant on the proportion of three main fatty acids viz ., oleic, linoleic and palmitic acid present in its oil (Derbyshire, 2014).…”

“…However, in 1987, Norden and co-workers identified the first high-oleate mutant lines, F435 with about 80% oleic acid and 2% linoleic acid. So far, more than 50 high-oleate peanut cultivars were registered worldwide, which are derived through traditional breeding, mutagenesis, marker-assisted selection (MAS) and marker assisted backcross breeding (MABB) (Wang et al, 2015c; Janila et al, 2016). Following conventional breeding methods, the first high oleate peanut line, “SunOleic95R” was bred in USA (Gorbet and Knauft, 1997); whereas, “Tifguard High O/L” was developed using MAS (Chu et al, 2011).…”