Conserved defense responses between maize and sorghum to Exserohilum turcicum

Abstract

Background: Exserohilum turcicum is an important pathogen of both sorghum and maize, causing sorghum leaf blight and northern corn leaf blight. Because the same pathogen can infect and cause major losses for two of the most important grain crops, it is an ideal pathosystem to study plant-pathogen evolution and investigate shared resistance mechanisms between the two plant species. To identify sorghum genes involved in the E. turcicum response, we conducted a genome-wide association study (GWAS). Results: Using the sorghum conversion panel evaluated across three environments, we identified a total of 216 significant markers. Based on physical linkage with the significant markers, we detected a total of 113 unique candidate genes, some with known roles in plant defense. Also, we compared maize genes known to play a role in resistance to E. turcicum with the association mapping results and found evidence of genes conferring resistance in both crops, providing evidence of shared resistance between maize and sorghum. Conclusions: Using a genetics approach, we identified shared genetic regions conferring resistance to E. turcicum in both maize and sorghum. We identified several promising candidate genes for resistance to leaf blight in sorghum, including genes related to R-gene mediated resistance. We present significant advancements in the understanding of host resistance to E. turcicum, which is crucial to reduce losses due to this important pathogen.

Differential Regulation of Maize and Sorghum Orthologs in Response to the Fungal Pathogen Exserohilum turcicum

“…WAKs have been implicated in major gene resistance in maize to several pathogens including E. turcicum ( Hurni et al, 2015 ; Zuo et al, 2015 ). The gene Sobic.002G249600 , encoding the wall-associated kinase 2, was significantly associated with SLB resistance ( Zhang et al, 2020 ) and significantly upregulated in the incompatible interaction at 72 hai in the current study. SRK are involved in self-incompatibility ( Zou et al, 2015 ), biotic stress ( Pastuglia et al, 1997 ) and abiotic stress ( Zou et al, 2015 ).…”

“…Two strains of E. turcicum were selected for inoculations: Et28A (maize-specific; received from B.G. Turgeon, Cornell University) ( Ohm et al, 2012 ) and 15St008 (sorghum-specific; isolated from symptomatic sorghum in Illinois) ( Zhang et al, 2020 ). There were three types of interactions: compatible (Et28A on maize and 15St008 on sorghum), incompatible (Et28A on sorghum and 15St008 on maize), and control (mock inoculation on maize and mock inoculation on sorghum) ( Table 1 ).…”

“…There is some evidence for shared resistance between maize and sorghum against E. turcicum ( Martin et al, 2011 ). A genome wide association study (GWAS) on the sorghum association panel identified candidate sorghum resistance genes with conserved function in maize ( Zhang et al, 2020 ). However, no previous studies have explored transcriptional responses to E. turcicum in both maize and sorghum.…”

Genetic variation associated with PPO-inhibiting herbicide tolerance in sorghum

“…A genotypic dataset (hereafter referred to as target set) scored using genotyping-by-sequencing was obtained for 718 lines of the SBP panel (See S1 File at https://doi.org/10.6084/m9.figshare.11551242.v1 ) from [ 10 ] and [ 11 ]. We increased the marker density for the target panel as described by [ 13 ]. A genome-wide re-sequencing dataset (hereafter referred to as reference set) was used for imputing un-typed SNPs [ 14 ].…”

“…11551242.v1) from [10] and [11]. We increased the marker density for the target panel as described by [13]. A genome-wide re-sequencing dataset (hereafter referred to as reference set) was used for imputing un-typed SNPs [14].…”