Four QTL clusters containing major and stable QTLs for saturated fatty acid contents in a dense genetic map of cultivated peanut (Arachis hypogaea L.)

Nian Liu,Fujian Xia,Huaiyong Luo,Boshou Liao,Yuning Chen,Huifang Jiang,Hao Chen,Xiaoping Ren,Weigang Chen,Xiaojing Zhou,Bei Wu,Li Huang,Dongxin Huai,Yong Lei

doi:10.1007/s11032-019-0934-2

Abstract

Peanut is an important source of edible vegetable oils worldwide. Saturated fatty acid content is a key factor that affects the quality of peanut oil; thus, reducing its content is a key objective in peanut breeding. In this study, we constructed a dense genetic map of recombinant inbred line (RIL) population (Zhonghua 10 × ICG 12625) with 1443 SSR loci, covering a total length of 2279.10 cM. Using phenotypic data from three environments, we have identified 59 additive QTLs including eight stable ones and nine epistatic QTLs for various fatty acids. Combination of conditional and unconditional QTL analyses further revealed that there was a high genetic correlation between stearic acid and very long-chain saturated fatty acids. In addition, four QTL clusters (CLB04-1, CLB04-2, CLB04-3, and CLB06) harboring major and stable QTLs for saturated fatty acids were identified, which explained 10.77–36.73%, 35.10–41.89%, 10.79–39.18%, and 4.85–20.32% phenotypic variations, respectively. The physical interval of four QTL clusters was located at pseudomolecule B04 and B06 of Arachis ipaensis, containing putative genes that encode enzymes and transcription factors involved in fatty acid biosynthesis pathways. This study comprehensively analyzed the genetic components that controlled saturated fatty acid profiles and identified four QTL clusters containing stable QTLs with large effects. Our results could provide a platform for further gene discovery and guide the development of markers for genome-wide assisted selection of varieties with desired components of saturated fatty acids.

Highlights

IntroductionPeanut oil is composed of eight fatty acids, i.e., palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1), linoleic acid (C18:2), arachidic acid (C20:0), gadoleic acid (C20:1), behenic acid (C22:0), and lignoceric acid (C24:0)
Peanut (Arachis hypogaea L., 2n = 4x = 40) is one of the most important oilseed crops, that is widely cultivated in over 100 countries
The Shapiro-Wilk test demonstrated that phenotypic data were normally distributed for palmitic acid, oleic acid, linoleic acid, behenic acid, and lignoceric acid; they were skewed towards lower values for stearic acid and arachidic acid (Table S1, Fig. 1)

Summary

Introduction

Peanut oil is composed of eight fatty acids, i.e., palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1), linoleic acid (C18:2), arachidic acid (C20:0), gadoleic acid (C20:1), behenic acid (C22:0), and lignoceric acid (C24:0). Unsaturated fatty acids, such as oleic acid and linoleic acid, accounted for 80% of peanut oil, influencing oil quality (Pandey et al 2014; Rizzo et al 1986; Vassiliou et al 2009). Other saturated fatty acids, such as stearic acid, arachidic acid, behenic acid, and lignoceric acid, have been associated with high risk of cardiovascular and multiple sclerosis diseases (Fretts et al 2014; Hon et al 2009; Siri-Tarino et al 2010). It is imperative to manipulate recombination of alleles associated with contents of saturated fatty acids to achieve optimized fatty acid composition in peanut

Methods

Results

Conclusion