背景:高粱炭疽病是阻碍全球作物生产力的主要疾病。该疾病是由半营养性真菌病原体Colletotrichumsublineola引起的。抗炭疽病高粱基因型的鉴定,定义抗性基因座和基础基因,它们渗入适应的品种对提高生产力至关重要。在这项研究中,我们对358种不同的埃塞俄比亚高粱进行了田间试验。在以适合抗病性筛查的严重自然侵染为特征的位置评估了对炭疽病的定量抗性。
结果:基于野外的筛选确定了53个在不同地点具有抗性的种质,而213个种质对局部致病型表现出可变的抗性。使用通过基因分型测序(GBS)产生的329个种质和83,861个单核苷酸多态性(SNP)的疾病反应评分进行了全基因组关联分析(GWAS)。我们确定了38个与炭疽病抗性显着相关的基因座。有趣的是,这些基因座的一个子集含有编码受体样激酶(RLK)的基因,核苷酸结合富含亮氨酸的重复序列(NLR),应激诱导的抗真菌酪氨酸激酶,以前与疾病抗性有关。4号染色体上的一个SNP(S04_66140995)和2号染色体上的两个SNP(S02_75784037,S02_2031925),定位于编码假定的应激诱导抗真菌激酶的基因的编码区,一种F盒蛋白,和Xa21结合RLK与炭疽病抗性密切相关。我们还确定了炭疽病抗性与与编码广为人知的NLR蛋白(RPM1)直向同源基因相关的三个SNP(Sobic.002G058400,Sobic.008G156600,Sobic.005G033400)之间的高度显著关联,富含亮氨酸的重复家族蛋白,和含有重金属相关结构域的蛋白质,分别。与预测的免疫反应基因相关的其他SNP也与炭疽病抗性显着相关。
结论:本研究中使用的高粱种质是遗传多样性的。它们有潜在的用处,但未被发现,抗炭疽病的等位基因。这得到了鉴定富含疾病抗性调节因子如NLR的新基因座的支持。LRK,Xa21绑定LRK,和抗真菌蛋白。这些种质的基因型数据为高粱育种者提供了有效改善作物的宝贵资源。鉴定的基因组区域和候选基因可用于设计高粱抗病性分子育种的标记。
BACKGROUND: Sorghum anthracnose is a major disease that hampers the productivity of the crop globally. The disease is caused by the hemibiotrophic fungal pathogen Colletotrichum sublineola. The identification of anthracnose-resistant sorghum genotypes, defining resistance loci and the underlying genes, and their introgression into adapted cultivars are crucial for enhancing productivity. In this study, we conducted field experiments on 358 diverse accessions of Ethiopian sorghum. Quantitative resistance to anthracnose was evaluated at locations characterized by a heavy natural infestation that is suitable for disease resistance screening.
RESULTS: The field-based screening identified 53 accessions that were resistant across locations, while 213 accessions exhibited variable resistance against local pathotypes. Genome-wide association analysis (GWAS) was performed using disease response scores on 329 accessions and 83,861 single nucleotide polymorphisms (SNPs) generated through genotyping-by-sequencing (GBS). We identified 38 loci significantly associated with anthracnose resistance. Interestingly, a subset of these loci harbor genes encoding receptor-like kinases (RLK), nucleotide-binding leucine-rich repeats (NLRs), stress-induced antifungal tyrosine kinase that have been previously implicated in disease resistance. A SNP on chromosome 4 (S04_66140995) and two SNPs on chromosome 2 (S02_75784037, S02_2031925), localized with-in the coding region of genes that encode a putative stress-induced antifungal kinase, an F-Box protein, and Xa21-binding RLK that were strongly associated with anthracnose resistance. We also identified highly significant associations between anthracnose resistance and three SNPs linked to genes (Sobic.002G058400, Sobic.008G156600, Sobic.005G033400) encoding an orthologue of the widely known NLR protein (RPM1), Leucine Rich Repeat family protein, and Heavy Metal Associated domain-containing protein, respectively. Other SNPs linked to predicted immune response genes were also significantly associated with anthracnose resistance.
CONCLUSIONS: The sorghum germplasm collections used in the present study are genetically diverse. They harbor potentially useful, yet undiscovered, alleles for anthracnose resistance. This is supported by the identification of novel loci that are enriched for disease resistance regulators such as NLRs, LRKs, Xa21-binding LRK, and antifungal proteins. The genotypic data available for these accessions offer a valuable resource for sorghum breeders to effectively improve the crop. The genomic regions and candidate genes identified can be used to design markers for molecular breeding of sorghum diseases resistance.