Association mapping of net blotch and spot blotch resistance in a set of Hordeum vulgare accessions originated from the centers of barley diversity

圆核腔菌引起的网斑病和玉米轮孢菌引起的斑点病是大麦上分布最广、危害最大的两种真菌病害。作为全俄植物保护研究所植物抗病性实验室（VIZR）和联邦栽培植物研究中心（JKI）抗性研究和抗逆性研究所长期联合研究项目的结果，对来自大麦多样性的不同遗传中心和商业品种的10.000份大麦种质进行了评价，C. sativus，结果鉴定了约450份具有不同抗性水平的种质。然而，到目前为止，非常有限的或没有信息的主基因或QTL参与这些种质的抗性。全基因组关联分析是一种有效的工具，可以在如此大量的材料中获得这一信息。本项目的目的是（i）确定玉米抗圆斑病的遗传多样性，并鉴定抗性QTL。teres，和圆叶拟单胞菌P.teresf. maculata和C. sativus在一个代表性的大麦种质资源收集中，采用全基因组关联研究（GWAS），（ii）通过在分离已经表型化的DH群体中整合相关标记来测试一些检测到的QTL的稳定性和可转移性，（iii）用标记使这些QTL饱和，并将这些QTL与大麦的物理和序列图谱联系起来，以鉴定候选基因，（iv）通过开发高效和廉价的PCR检测来提高这些QTL在育种中的使用。为了实现这一目标，将在JKI和VIZR对450份大麦种质进行表型分析，通过接种不同的圆斑病菌分离株进行抗性鉴定。teres，圆叶假单胞菌P.teresf. maculata和C. sativus起源于俄罗斯和德国，以获得详细的信息，抵抗。对于基因分型，将使用目前在JKI建立的Illumina 9k iSelect大麦芯片和测序基因分型（GBS），并将在每个染色体臂的两个SSR上估计群体结构。基于这些GWAS，预期大麦编码对P.teres f. teres，圆叶假单胞菌P.teresf. maculata和C.将被识别。作为基于图谱的克隆方法的第一步，各个QTL区域将标记饱和。利用这种方法，将获得有关上述病原体的抗性遗传多样性的详细信息，相应的标记将有助于在大麦育种中直接利用这种多样性。

Net blotch caused by Pyrenophora teres and spot blotch caused by Cochliobolus sativus are two most damaging and widely distributed fungal pathogens of barley. As a result of long-term joint research projects of the Laboratory of Plant Resistance to Diseases of the All-Russian Research Institute of Plant Protection (VIZR) and the Institute for Resistance Research and Stress Tolerance of the Federal Research Center for Cultivated Plants (JKI), 10.000 barley accessions from different genetic centers of barley diversity and commercial cultivars were evaluated for resistance to both P. teres and C. sativus, and as a result about 450 accessions with different levels of resistance were identified. However, up to now very limited or no information on major genes or QTL involved in resistance of these accessions is available. To get this information in such a large number of accessions, genome wide association studies are an efficient tool facilitating the analyses of a much broader diversity than analyses in bi-parental populations.The objectives of the project are (i) to determine the genetic diversity of resistance and identify QTL for resistance to P. teres f. teres, and P. teres f. maculata as well as to C. sativus in a representative barley germplasm collection employing genome wide association studies (GWAS), (ii) to test the stability and transferability of some detected QTL by integrating associated markers in segregating already phenotyped DH-populations, (iii) to saturate these QTL with markers and to link these to the physical and sequence maps of barley towards the identification of candidate genes, (iv) to enhance the use of these QTL in breeding by developing efficient and cheap PCR assays. To achieve this, 450 barley accessions will be phenotyped at the JKI and the VIZR for resistance by inoculation with different isolates of P. teres f. teres, P. teres f. maculata, and C. sativus originated from Russia and Germany to get detailed information on resistance. For genotyping, the Illumina 9k iSelect barley Chip and genotyping by sequencing (GBS) currently under establishment at JKI will be used and population structure will be estimated on two SSRs per chromosome arm. GWAS will be conducted using a mixed linear model approach. Based on these GWAS it is expected that most of the genomic regions of barley encoding resistance to P. teres f. teres, P. teres f. maculata, and C. sativus will be identified. Respective QTL regions will be marker saturated as a first step towards a map based cloning approach. Using this approach detailed information on the genetic diversity of resistance concerning the above mentioned pathogens will be gained and respective markers will facilitate a directed use of this diversity in barley breeding.