Reinprecht Yarmilla, Pauls K Peter
Department of Plant Agriculture, University of Guelph Guelph, ON, Canada.
Front Genet. 2016 Mar 29;7:38. doi: 10.3389/fgene.2016.00038. eCollection 2016.
High levels of linolenic acid (80 g kg(-1)) 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(-1) 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 (>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 FAD3 genes. Four FAD3 genes were sequenced and localized in RG10 and OX948 and compared to the genes in the reference Williams 82 genome. The FAD3A gene sequences mapped to the locus Glyma.14g194300 [on the chromosome Gm14 (B2)], which is syntenic to the FAD3B gene (locus Glyma.02g227200) on the chromosome Gm02 (D1b). The location of the FAD3A gene is the same as was previously determined for the fan 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 FAD3B 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 in silico position of the FAD3B gene sequences. FAD3C and FAD3D 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 FAD3A and FAD3B, their validation in an independent population, and development of FAD3 gene-specific markers should simplify and accelerate breeding for low linolenic acid soybean cultivars.
高含量的亚麻酸（80克/千克）与大豆油中异味的产生以及稳定性差有关。低亚麻酸品系如RG10（亚麻酸含量为20克/千克）的培育可以减少这些问题。种子油中亚麻酸的含量由微粒体ω-3脂肪酸去饱和酶（FAD3）的活性决定。先前在RG10×OX948杂交产生的重组自交系群体中，在连锁群B2（染色体Gm14）上检测到一个主要的亚麻酸QTL（变异贡献率>70%）。本研究的目的是在一个独立群体中验证这个主要的亚麻酸QTL，并对所有大豆FAD3基因进行表征。对四个FAD3基因进行了测序，并定位到RG10和OX948中，然后与参考基因组Williams 82中的基因进行比较。FAD3A基因序列定位于位点Glyma.14g194300[在染色体Gm14（B2）上]，它与染色体Gm02（D1b）上的FAD3B基因（位点Glyma.02g / 227200）是同线的。FAD3A基因的位置与先前确定的fan等位基因相同，该等位基因决定低亚麻酸含量以及几个亚麻酸QTL，包括先前在RG10×OX948群体中定位并在PI 361088B×OX948群体中确认为Linolen - PO（FAD3A）的Linolen 3 - 3。先前开发的基于FAD3B基因的标记，在RG10×OX948遗传图谱中定位到染色体Gm02（D1b）上一个包含新检测到的亚麻酸QTL[Linolen - RO（FAD3B）]的区域，并且与FAD3B基因序列的电子定位很好地对应。FAD3C和FAD3D基因序列分别定位于染色体Gm18（位点Glyma.18g062000）和Gm11（位点Glyma.11g227200）的同线区域。亚麻酸QTL与去饱和酶基因FAD3A和FAD3B的关联、在独立群体中的验证以及FAD3基因特异性标记的开发，应该会简化并加速低亚麻酸大豆品种的育种进程。
