AUTHOR=Reinprecht Yarmilla , Pauls K. Peter 

TITLE=Microsomal Omega-3 Fatty Acid Desaturase Genes in Low Linolenic Acid Soybean Line RG10 and Validation of Major Linolenic Acid QTL

JOURNAL=Frontiers in Genetics

VOLUME=7

YEAR=2016

URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2016.00038

DOI=10.3389/fgene.2016.00038

ISSN=1664-8021

ABSTRACT=<p>High levels of linolenic acid (80 g kg<sup>−1</sup>) are associated with the development of off-flavors and poor stability in soybean oil. The development of low linolenic acid lines such as RG10 (20 g kg<sup>−1</sup> linolenic acid) can reduce these problems. The level of linolenic acid in seed oil is determined by the activities of microsomal omega-3 fatty acid desaturases (FAD3). A major linolenic acid QTL (&gt;70% of variation) on linkage group B2 (chromosome Gm14) was previously detected in a recombinant inbred line population from the RG10 × OX948 cross. The objectives of this study were to validate the major linolenic acid QTL in an independent population and characterize all the soybean <italic>FAD3</italic> genes. Four <italic>FAD3</italic> genes were sequenced and localized in RG10 and OX948 and compared to the genes in the reference Williams 82 genome. The <italic>FAD3A</italic> gene sequences mapped to the locus Glyma.14g194300 [on the chromosome Gm14 (B2)], which is syntenic to the <italic>FAD3B</italic> gene (locus Glyma.02g227200) on the chromosome Gm02 (D1b). The location of the <italic>FAD3A</italic> gene is the same as was previously determined for the <italic>fan</italic> allele, that conditions low linolenic acid content and several linolenic acid QTL, including Linolen 3-3, mapped previously with the RG10 × OX948 population and confirmed in the PI 361088B × OX948 population as Linolen-PO (FAD3A). The <italic>FAD3B</italic> gene-based marker, developed previously, was mapped to the chromosome Gm02 (D1b) in a region containing a newly detected linolenic acid QTL [Linolen-RO(FAD3B)] in the RG10 × OX948 genetic map and corresponds well with the <italic>in silico</italic> position of the <italic>FAD3B</italic> gene sequences. <italic>FAD3C</italic> and <italic>FAD3D</italic> gene sequences, mapped to syntenic regions on chromosomes Gm18 (locus Glyma.18g062000) and Gm11 (locus Glyma.11g227200), respectively. Association of linolenic acid QTL with the desaturase genes <italic>FAD3A</italic> and <italic>FAD3</italic>B, their validation in an independent population, and development of <italic>FAD3</italic> gene-specific markers should simplify and accelerate breeding for low linolenic acid soybean cultivars.</p>