Department of Agronomy, Iowa State University, Ames, Iowa, United States of America.
Department of Computer Science, Iowa State University, Ames, Iowa, United States of America.
PLoS One. 2019 Feb 26;14(2):e0212071. doi: 10.1371/journal.pone.0212071. eCollection 2019.
Fusarium virguliforme is a soil borne root pathogen that causes sudden death syndrome (SDS) in soybean [Glycine max (L.) Merrill]. Once the fungus invades the root xylem tissues, the pathogen secretes toxins that cause chlorosis and necrosis in foliar tissues leading to defoliation, flower and pod drop and eventually death of plants. Resistance to F. virguliforme in soybean is partial and governed by over 80 quantitative trait loci (QTL). We have conducted genome-wide association study (GWAS) for a group of 254 plant introductions lines using a panel of approximately 30,000 SNPs and identified 19 single nucleotide polymorphic loci (SNPL) that are associated with 14 genomic regions encoding foliar SDS and eight SNPL associated with seven genomic regions for root rot resistance. Of the identified 27 SNPL, six SNPL for foliar SDS resistance and two SNPL for root rot resistance co-mapped to previously identified QTL for SDS resistance. This study identified 13 SNPL associated with eight novel genomic regions containing foliar SDS resistance genes and six SNPL with five novel regions for root-rot resistance. This study identified five genes carrying nonsynonymous mutations: (i) three of which mapped to previously identified QTL for foliar SDS resistance and (ii) two mapped to two novel regions containing root rot resistance genes. Of the three genes mapped to QTL for foliar SDS resistance genes, two encode LRR-receptors and third one encodes a novel protein with unknown function. Of the two genes governing root rot resistance, Glyma.01g222900.1 encodes a soybean-specific LEA protein and Glyma.10g058700.1 encodes a heparan-alpha-glucosaminide N-acetyltransferase. In the LEA protein, a conserved serine residue was substituted with asparagine; and in the heparan-alpha-glucosaminide N-acetyltransferase, a conserved histidine residue was substituted with an arginine residue. Such changes are expected to alter functions of these two proteins regulated through phosphorylation. The five genes with nonsynonymous mutations could be considered candidate SDS resistance genes and should be suitable molecular markers for breeding SDS resistance in soybean. The study also reports desirable plant introduction lines and novel genomic regions for enhancing SDS resistance in soybean.
尖镰孢是一种土壤传播的根病原体，可导致大豆（Glycine max (L.) Merrill）猝倒病（SDS）。一旦真菌侵入根木质部组织，病原体就会分泌毒素，导致叶片组织出现黄化和坏死，导致落叶、落花和落荚，最终导致植物死亡。大豆对尖镰孢的抗性是部分的，由 80 多个数量性状位点 (QTL) 控制。我们使用大约 30,000 个 SNP 的面板对 254 个植物引种系进行了全基因组关联研究 (GWAS)，并鉴定出与 14 个编码叶片 SDS 的基因组区域和与 7 个根腐病抗性基因组区域相关的 19 个单核苷酸多态性 (SNPL) 。在所鉴定的 27 个 SNPL 中，有 6 个与叶片 SDS 抗性相关的 SNPL 和 2 个与根腐病抗性相关的 SNPL 与先前鉴定的 SDS 抗性 QTL 共定位。这项研究鉴定出 13 个与包含叶片 SDS 抗性基因的 8 个新基因组区域相关的 SNPL 和 6 个与包含根腐病抗性基因的 5 个新区域相关的 SNPL。这项研究鉴定出五个携带非同义突变的基因：（i）其中三个映射到先前鉴定的叶片 SDS 抗性 QTL，（ii）两个映射到包含根腐病抗性基因的两个新区域。在映射到叶片 SDS 抗性基因 QTL 的三个基因中，有两个编码 LRR-受体，第三个编码具有未知功能的新型蛋白。在控制根腐病抗性的两个基因中，Glyma.01g222900.1 编码一种大豆特异性 LEA 蛋白，Glyma.10g058700.1 编码一种肝素-α-葡糖胺 N-乙酰转移酶。在 LEA 蛋白中，保守的丝氨酸残基被天冬酰胺取代；而在肝素-α-葡糖胺 N-乙酰转移酶中，保守的组氨酸残基被精氨酸取代。这些变化预计会改变通过磷酸化调节的这两种蛋白质的功能。这五个具有非同义突变的基因可以被认为是 SDS 抗性候选基因，并且应该是大豆 SDS 抗性育种的合适分子标记。该研究还报告了增强大豆 SDS 抗性的理想植物引种系和新的基因组区域。
