Genetic Characterization of Resistance to Pyrenophora teres f. teres in the International Barley Differential Canadian Lake Shore

Abstract

Genetic resistance to net form of net blotch in the international barley differential Canadian Lake Shore (CLS) was characterized and mapped. A doubled haploid (DH) population generated from a cross between CLS and susceptible cultivar Harrington was evaluated at the seedling stage using eight diverse Pyrenophora teres f. teres ( Ptt ) isolates and at the adult stage in the field using natural inoculum. To effectively map the CLS resistance, comparative marker frequency analysis (MFA) was performed using 8,762 polymorphic DArT-seq markers, where ‘resistant’ and ‘susceptible’ groups each comprised 40 DH lines displaying the most extreme phenotypes. Five DArTseq markers were consistently detected in eight disease assays, which was designated qPttCLS and deemed to harbor the locus underpinning CLS resistance. Four of these markers were present onto the barley DArTseq physical map and spans a region between 398203862 and 435526243 bp which were found to consist several genes involved in important plant functions such as disease response and signaling pathways. While MFA only detected the 3H region, genetic analyses based on segregation patterns were inconsistent, suggesting complex inheritance or variation in phenotypic expression of qPttCLS , particularly in the field. This study represents progress toward connecting Ptt pathotype surveys with the corresponding resistance genes in barley differentials. The markers associated with qPttCLS are useful for marker-assisted selection in breeding programs.

Fine mapping qGL2H, a major locus controlling grain length in barley (Hordeum vulgare L.)

“…Development of tightly linked molecular markers to underlying candidate genes and identification of desirable alleles is necessary for effective MAS. Diagnostic molecular markers have been identified for numerous traits such as waterlogging tolerance (Zhang et al 2016); malting quality (Gong et al 2013;Xu et al 2018b) and disease resistance (Dinglasan et al 2019;Zantinge et al 2019). Despite numerous studies having mapped significant QTL associated with grain size characteristics on all seven barley chromosomes, limited research fine mapping these regions has impacted the development of diagnostic molecular markers for breeding purposes.…”

The Barley HvWRKY6 Transcription Factor Is Required for Resistance Against Pyrenophora teres f. teres

“…However, the first two mutants identified were allelic and mapped to the 3H QTL identified in the CI5791 x Tifang biparental mapping by Koladia et al (2017) ( Figure 2 ; Koladia et al, 2017 ) and disrupted the HvWRKY6 transcription factor that plays a role in arresting pathogen colonization and spread after penetration. Additional studies have also reported large QLT intervals over chromosome 3H that spanned from 36.26 to 76.56 cM ( Dinglasan et al, 2019 ). However, a smaller interval (51.27–51.77 cM) was consistently reported and designated as qPttCLS , that maps physically to 398.2–435.5 Mbp on the Morex reference genome ( Mascher et al, 2017 ) and therefore is not suspected to encompass HvWRKY6 .…”

Pyrenophora teres: Population structure, virulence and aggressiveness in Southern Russia

“…We did an experiment to determine the racial structure of the pathogen population using an international set of differentiating cultivars ( Afanasenko et al, 2009 , Dinglasan et al, 2019 ). We used for the experiment 30 P. teres isolates from each cultivar.…”

“…Some researchers ( Poudel et al, 2017 , Dinglasan et al, 2019 , Vasighzadeh et al, 2021 ), studying the genetic structure of P. teres , note the high genetic diversity of the pathogen. The principles of maintaining crop genetic diversity through cultivar diversity can significantly reduce the incidence.…”