Detection and molecular characterization of two FAD3 genes controlling linolenic acid content and development of allele-specific markers in yellow mustard (Sinapis alba).

Entang Tian,Fangqin Zeng,Vicky Roslinsky,Bifang Cheng,Kimberly Mackay,Xianlong Zhang

doi:10.1371/journal.pone.0097430

Abstract

Development of yellow mustard (Sinapis alba L.) with superior quality traits (low erucic and linolenic acid contents, and low glucosinolate content) can make this species as a potential oilseed crop. We have recently isolated three inbred lines Y1127, Y514 and Y1035 with low (3.8%), medium (12.3%) and high (20.8%) linolenic acid (C18∶3) content, respectively, in this species. Inheritance studies detected two fatty acid desaturase 3 (FAD3) gene loci controlling the variation of C18∶3 content. QTL mapping revealed that the two FAD3 gene loci responsible for 73.0% and 23.4% of the total variation and were located on the linkage groups Sal02 and Sal10, respectively. The FAD3 gene on Sal02 was referred to as SalFAD3.LA1 and that on Sal10 as SalFAD3.LA2. The dominant and recessive alleles were designated as LA1 and la1 for SalFAD3.LA1, and LA2 and la2 for SalFAD3.LA2. Cloning and alignment of the coding and genomic DNA sequences revealed that the SalFAD3.LA1 and SalFAD3.LA2 genes each contained 8 exons and 7 introns. LA1 had a coding DNA sequence (CDS) of 1143 bp encoding a polypeptide of 380 amino acids, whereas la1 was a loss-of-function allele due to an insertion of 584 bp in exon 3. Both LA2 and la2 had a CDS of 1152 bp encoding a polypeptide of 383 amino acids. Allele-specific markers for LA1, la1, LA2 and la2 co-segregated with the C18∶3 content in the F2 populations and will be useful for improving fatty acid composition through marker assisted selection in yellow mustard breeding.

Highlights

Yellow mustard (Sinapis alba L., 2n = 24) is cultivated as an important condiment crop
Yellow mustard germplasm with canola quality was developed at Agriculture and Agri-Food Canada-Saskatoon Research Centre (AAFC-SRC) [5], which makes yellow mustard have the potential to become an alternative oilseed crop to canola B. napus, especially in semi-arid areas
The present paper reported on the inheritance and QTL mapping of C18:3 content as well as molecular characterization of the fatty acid desaturase 3 (FAD3) genes in yellow mustard

Summary

Introduction

Yellow mustard (Sinapis alba L., 2n = 24) is cultivated as an important condiment crop. It has many desirable agronomic traits such as resistance to cabbage aphids [1], flea beetles [2,3] and blackleg diseases [4]. The oil quality of canola B. napus is determined by the proportion of the three major unsaturated fatty acids: oleic acid (C18:1), linoleic acid (C18:2) and linolenic acid (C18:3). Traditional B. napus cultivars contain 9% C18:3 of the total fatty acids [6]. A low linolenic acid mutant, containing 3–5% C18:3, was produced by ethyl methanesulfonate (EMS) treatment of a high C18:3 B. napus cv. Current low C18:3 canola cultivars have been developed using this low linolenic gene source

Objectives

Methods

Results

Conclusion