PDF(Pubmed)
Abstract：
The soilborne oomycete plant pathogen Pythium ultimum causes seed rot and pre-emergence damping-off of chickpea (Cicer arietinum L.). The pathogen has been controlled for several decades using the fungicide metalaxyl as seed treatment but has re-emerged as a severe problem with the detection of metalaxyl-resistant isolates of the pathogen from infested fields in the United States Pacific Northwest. The objective of this study was to identify genetic markers and candidate genes associated with resistance to P. ultimum in an interspecific recombinant inbred line population (CRIL-7) derived from a cross between C. reticulatum (PI 599072) x C. arietinum (FLIP 84-92C) and conduct genome-wide association studies (GWAS) for disease resistance using a chickpea diversity panel consisting of 184 accessions. CRIL-7 was examined using 1029 SNP markers spanning eight linkage groups. A major QTL, \"qpsd4-1,\" was detected on LG 4 that explained 41.8% of phenotypic variance, and a minor QTL, \"qpsd8-1,\" was detected on LG8 that explained 4.5% of phenotypic variance. Seven candidate genes were also detected using composite interval mapping including several genes previously associated with disease resistance in other crop species. A total of 302,902 single nucleotide polymorphic (SNP) markers were used to determine population structure and kinship of the diversity panel. Marker-trait associations were established by employing different combinations of principal components (PC) and kinships (K) in the FarmCPU model. Genome-wide association studies detected 11 significant SNPs and seven candidate genes associated with disease resistance. SNP Ca4_1765418, detected by GWAS on chromosome 4, was located within QTL qpsd4-1 that was revealed in the interspecific CRIL-7 population. The present study provides tools to enable MAS for resistance to P. ultimum and identified genomic domains and candidate genes involved in the resistance of chickpea to soilborne diseases.
摘要：
土壤传播的卵菌植物病原体霉霉会导致鹰嘴豆（CicerarietinumL.）的种子腐烂和出苗前的阻尼。使用杀菌剂甲霜灵作为种子处理已经控制了病原体数十年，但是在美国西北太平洋受感染的田地中检测到对甲霜灵具有抗性的病原体分离株，这是一个严重的问题。这项研究的目的是鉴定种间重组自交系种群（CRIL-7）中与对P.ultimum抗性相关的遗传标记和候选基因。网纹衣原体（PI599072）xC.arietinum（FLIP84-92C），并使用由184个种质组成的鹰嘴豆多样性小组进行全基因组关联研究（GWAS）抗病性。使用跨越8个连锁组的1029个SNP标记检查CRIL-7。一个主要的QTL，在LG4上检测到“qpsd4-1”，解释了41.8%的表型变异，和一个小QTL，在LG8上检测到“qpsd8-1”，解释了4.5%的表型变异。还使用复合间隔作图检测了七个候选基因，其中包括先前与其他作物物种的抗病性相关的几个基因。总共使用302,902个单核苷酸多态性（SNP）标记来确定多样性小组的种群结构和亲缘关系。通过在FarmCPU模型中采用主成分（PC）和亲缘关系（K）的不同组合来建立标记-性状关联。全基因组关联研究检测到11个显著的SNP和7个与疾病抗性相关的候选基因。GWAS在4号染色体上检测到的SNPCa4_1765418位于种间CRIL-7群体中揭示的QTLqpsd4-1内。本研究提供了使MAS能够对大豆产生抗性的工具，并确定了与鹰嘴豆对土壤传播疾病的抗性有关的基因组结构域和候选基因。
