Bridging Classical and Molecular Genetics of Sorghum Disease Resistance

Magill, Clint

doi:10.1007/978-1-4419-5947-8_15

Cited by 2 publications

(1 citation statement)

References 57 publications

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“…The highly diverse sorghum germplasm may exhibit varied disease phenotypes, although these interactions have not yet been characterized. While genome sequences are available for sorghum and Xvh [ 15 , 16 ], relatively little research has been conducted on the molecular basis of sorghum- Xvh interactions [ 17 , 18 ]. Here, we conducted a large-scale screen for resistance or susceptibility to Xvh in diverse sorghum genotypes and identified a range of disease phenotypes.…”

Section: Introductionmentioning

confidence: 99%

Escalation in the host-pathogen arms race: A host resistance response corresponds to a heightened bacterial virulence response

et al. 2021

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The zig-zag model of host-pathogen interaction describes the relative strength of defense response across a spectrum of pathogen-induced plant phenotypes. A stronger defense response results in increased resistance. Here, we investigate the strength of pathogen virulence during disease and place these findings in the context of the zig-zag model. Xanthomonas vasicola pv. holcicola (Xvh) causes sorghum bacterial leaf streak. Despite being widespread, this disease has not been described in detail at the molecular level. We divided diverse sorghum genotypes into three groups based on disease symptoms: water-soaked lesions, red lesions, and resistance. Bacterial growth assays confirmed that these three phenotypes represent a range of resistance and susceptibility. To simultaneously reveal defense and virulence responses across the spectrum of disease phenotypes, we performed dual RNA-seq on Xvh-infected sorghum. Consistent with the zig-zag model, the expression of plant defense-related genes was strongest in the resistance interaction. Surprisingly, bacterial virulence genes related to the type III secretion system (T3SS) and type III effectors (T3Es) were also most highly expressed in the resistance interaction. This expression pattern was observed at multiple time points within the sorghum-Xvh pathosystem. Further, a similar expression pattern was observed in Arabidopsis infected with Pseudomonas syringae for effector-triggered immunity via AvrRps4 but not AvrRpt2. Specific metabolites were able to repress the Xvh virulence response in vitro and in planta suggesting a possible signaling mechanism. Taken together, these findings reveal multiple permutations of the continually evolving host-pathogen arms race from the perspective of host defense and pathogen virulence responses.

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Section: Introductionmentioning

confidence: 99%

Escalation in the host-pathogen arms race: A host resistance response corresponds to a heightened bacterial virulence response

et al. 2021

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Host Determinants of Fungal Species Composition and Symptom Manifestation in the Sorghum Grain Mold Disease Complex

et al. 2023

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Sorghum grain mold (SGM) is an important multifungal disease complex affecting sorghum (Sorghum bicolor) production systems worldwide. SGM-affected sorghum grain can be contaminated with potent fumonisin mycotoxins produced by Fusarium verticillioides, a prevalent SGM-associated taxon. Historically, efforts to improve resistance to SGM have achieved only limited success. Classical approaches to evaluating SGM resistance are based solely on disease severity, which offers little insight regarding the distinct symptom manifestations within the disease complex. In this study, three novel phenotypes were developed to facilitate assessment of SGM symptom manifestation. A sorghum diversity panel composed of 390 accessions was inoculated with endogenous strains of F. verticillioides and evaluated for these phenotypes, as well as for the conventional panicle grain mold severity rating phenotype, in South Carolina, U.S.A., in 2017 and 2019. Distributions of phenotype values were examined, broad-sense heritability was estimated, and relationships to botanical race were explored. A typology of SGM symptom manifestations was developed to classify accessions using principal component analysis and k-means clustering, constituting a novel option for basing breeding decisions on SGM outcomes more nuanced than disease severity. Genome-wide association studies were performed using SGM trait data, resulting in the identification of 19 significant single nucleotide polymorphisms in linkage disequilibrium with a total of 86 gene models. Our findings provide a basis of exploratory evidence regarding the genetic architecture of SGM symptom manifestation and indicate that traits other than disease severity could be tractable targets for SGM resistance breeding.

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Bridging Classical and Molecular Genetics of Sorghum Disease Resistance

Cited by 2 publications

References 57 publications

Escalation in the host-pathogen arms race: A host resistance response corresponds to a heightened bacterial virulence response

Escalation in the host-pathogen arms race: A host resistance response corresponds to a heightened bacterial virulence response

Host Determinants of Fungal Species Composition and Symptom Manifestation in the Sorghum Grain Mold Disease Complex

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