Duarte-Delgado Diana, Juyó Deissy, Gebhardt Christiane, Sarmiento Felipe, Mosquera-Vásquez Teresa
Faculty of Agricultural Sciences, Agronomy Department, National University of Colombia, Bogotá, Colombia.
Present address: INRES-Plant Breeding, University of Bonn, Bonn, Germany.
BMC Genet. 2017 Mar 9;18(1):23. doi: 10.1186/s12863-017-0489-3.
Potato frying color is an agronomic trait influenced by the sugar content of tubers. The candidate gene approach was employed to elucidate the molecular basis of this trait in Solanum tuberosum Group Phureja, which is mainly diploid and represents an important genetic resource for potato breeding. The objective of this research was to identify novel genetic variants related with frying quality in loci with key functions in carbohydrate metabolism, with the purpose of discovering genetic variability useful in breeding programs. Therefore, an association analysis was implemented with 109 SNP markers identified in ten candidate genes.
The analyses revealed four associations in the locus InvGE coding for an apoplastic invertase and one association in the locus SssI coding for a soluble starch synthase. The SNPs SssI-C T and InvGE-C T were associated with sucrose content and frying color, respectively, and were not found previously in tetraploid genotypes. The rare haplotype InvGE-A C A was associated with higher fructose contents. Our study allowed a more detailed analysis of the sequence variation of exon 3 from InvGE, which was not possible in previous studies because of the high frequency of insertion-deletion polymorphisms in tetraploid potatoes.
The association mapping strategy using a candidate gene approach in Group Phureja allowed the identification of novel SNP markers in InvGE and SssI associated with frying color and the tuber sugar content measured by High Performance Liquid Chromatography (HPLC). These novel associations might be useful in potato breeding programs for improving quality traits and to increase crop genetic variability. The results suggest that some genes involved in the natural variation of tuber sugar content and frying color are conserved in both Phureja and tetraploid germplasm. Nevertheless, the associated variants in both types of germplasm were present in different regions of these genes. This study contributes to the understanding of the genetic architecture of tuber sugar contents and frying color at harvest in Group Phureja.
马铃薯油炸色泽是一种受块茎含糖量影响的农艺性状。采用候选基因法来阐明该性状在马铃薯普通栽培种中的分子基础，该栽培种主要为二倍体，是马铃薯育种的重要遗传资源。本研究的目的是在碳水化合物代谢关键功能位点中鉴定与油炸品质相关的新遗传变异，以便发现对育种计划有用的遗传变异性。因此，对在10个候选基因中鉴定出的109个单核苷酸多态性（SNP）标记进行了关联分析。
分析揭示了在编码质外体转化酶的InvGE位点有4个关联，在编码可溶性淀粉合酶的SssI位点有1个关联。SssI-C>T和InvGE-C>T这两个SNP分别与蔗糖含量和油炸色泽相关，且此前在四倍体基因型中未发现。罕见单倍型InvGE-A>C>A与较高的果糖含量相关。我们的研究能够更详细地分析InvGE外显子3的序列变异，而此前由于四倍体马铃薯中插入缺失多态性频率较高，在研究中无法做到这一点。
在普通栽培种中采用候选基因法的关联作图策略，使得能够在InvGE和SssI中鉴定出与油炸色泽以及通过高效液相色谱（HPLC）测定的块茎含糖量相关的新SNP标记。这些新的关联可能有助于马铃薯育种计划改善品质性状并增加作物遗传变异性。结果表明，一些参与块茎含糖量和油炸色泽自然变异的基因在普通栽培种和四倍体种质中都是保守的。然而，这两种种质中的相关变异存在于这些基因的不同区域。本研究有助于理解普通栽培种收获时块茎含糖量和油炸色泽的遗传结构。
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