Genetic analysis of novel resistance sources and genome-wide association mapping identified novel QTLs for resistance to Zymoseptoria tritici, the causal agent of septoria tritici blotch in wheat

Abstract

Septoria tritici blotch (STB) caused by Zymoseptoria tritici is one of the most important foliar diseases of wheat causing signi cant yield losses worldwide. In this study, a panel of bread wheat genotypes comprised 185 globally diverse genotypes were tested against 10 Z. tritici isolates at the seedling stage. Genome-wide association study (GWAS) using high-throughput DArTseq markers was performed and further gene expression analysis of signi cant markers trait association (MTAs) associated with resistance to STB was analyzed. Disease severity level showed signi cant differences among wheat genotypes for resistance to different Z. tritici isolates. We found novel landrace genotypes that showed highly resistance spectra to all tested isolates. GWAS analysis resulted in 19 quantitative trait loci (QTLs) for resistance to STB that were located on 14 chromosomes. Overall, 14 QTLs were overlapped with previously known QTLs or resistance genes, as well as ve potentially novel QTLs on chromosomes 1A, 4A, 5B, 5D and 6D. Identi ed novel resistance sources and also novel QTLs for resistance to different Z. tritici isolates can use for pyramiding and development of durable resistance cultivars in future wheat breeding programs.

Multi-stage resistance to Zymoseptoria tritici revealed by GWAS in an Australian bread wheat diversity panel

“…The level of phenotypic variance explained by the identified QTLs ranged from 3.1% to 6.9% ( Table 2 ), even though some of the loci are putative major genes as discussed below. Similar levels of explained variation, 2-11% have been reported in the eight published Zymoseptoria resistance GWAS studies using high-density SNP markers ( Kidane et al., 2017 ; Vagndorf et al., 2017 ; Würschum et al., 2017 ; Muqaddasi et al., 2019 ; Yates et al., 2019 ; Alemu et al., 2021 ; Louriki et al., 2021 ; Mahboubi et al., 2022 ). It is a reasonable assumption that in a in a diverse germplasm collection such as AusSTB that the Zymoseptoria resistance is controlled by multiple QTLs with small effects.…”

“…Different types of quantitative resistance have been identified in 89 genomic regions in wheat, of which, 27 were detected at the seedling stage, and 48 at the adult stage ( Goudemand et al., 2013 ; Brown et al., 2015 ). New quantitative trait loci (QTLs) at the adult-plant stage have also been detected from ten GWAS studies ( Arraiano and Brown, 2017 ; Kidane et al., 2017 ; Vagndorf et al., 2017 ; Würschum et al., 2017 ; Muqaddasi et al., 2019 ; Yates et al., 2019 ; Riaz et al., 2020 ; Alemu et al., 2021 ; Louriki et al., 2021 ; Mahboubi et al., 2022 ). These include notable loci such as QStb.NS-2A associated with APR ( Vagndorf et al., 2017 ), qtl-3 on the control of necrosis lesions ( Yates et al., 2019 ), and QStb.teagasc-4A.1 associated with the STB resistance of flag leaves and flag-1 leaves ( Riaz et al., 2020 ).…”

Physiological specialization of Puccinia triticina and genome-wide association mapping provide insights into the genetics of wheat leaf rust resistance in Iran

“…www.nature.com/scientificreports/ Genetic diversity, population structure and linkage disequilibrium (LD). The genetic diversity and population structure of 185 wheat genotypes were previously described 73 . Briefly, Cluster analysis of diversity panel estimated in DARwin ver.…”

“…In the model, the genotype considered as a fixed effect and replication (block) considered as random effect. These BLUE values were then used for broad sense heritability estimates and correlations between isolates, cluster analysis of wheat genotypes and also to perform GWAS 73 . Genome-wide association mapping (GWAS) analysis was conducted in the R package Genome Association and Prediction Integrated Tool (GAPIT) 76 using all 21,773 mapped polymorphic DArTseq markers.…”

Multi-stage resistance toZymoseptoria triticirevealed by GWAS in an Australian bread wheat (Triticum aestivumL.) diversity panel

“…Different types of quantitative resistance have been identified in 89 genomic regions in wheat, of which, 27 were detected at the seedling stage, and 48 at the adult stage (Brown et al 2015;Goudemand et al 2013). New quantitative trait loci (QTLs) at the adult-plant stage have also been detected from nine GWAS studies (Alemu et al 2021;Arraiano and Brown 2017;Kidane et al 2017;Louriki et al 2021;Mahboubi et al 2022;Muqaddasi et al 2019;Riaz et al 2020;Vagndorf et al 2017;Würschum et al 2017;Yates et al 2019). These include notable loci such as QStb.NS-2A associated with APR (Vagndorf et al 2017), qtl-3 on the control of necrosis lesions (Yates et al 2019), and QStb.teagasc-4A.1 associated with the STB resistance of flag leaves and flag-1 leaves (Riaz et al 2020).…”