Sugar Beet Diseases: Cercospora Leaf Spot

Khan, Mohamed F. R.

doi:10.1007/978-4-431-55642-8_23

Cited by 5 publications

(2 citation statements)

References 17 publications

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“…Cercospora leaf spot (CLS), which is caused by the fungus Cercospora beticola Sacc., is one of the most serious leaf diseases for sugar beet ( Beta vulgaris L.) worldwide [1,2]. As the disease progresses, infected leaves exhibit numerous leaf spot lesions, which lead to complete leaf collapse.…”

Section: Introductionmentioning

confidence: 99%

NMR-Based Metabolic Profiling of Field-Grown Leaves from Sugar Beet Plants Harbouring Different Levels of Resistance to Cercospora Leaf Spot Disease

et al. 2017

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Cercospora leaf spot (CLS) is one of the most serious leaf diseases for sugar beet (Beta vulgaris L.) worldwide. The breeding of sugar beet cultivars with both high CLS resistance and high yield is a major challenge for breeders. In this study, we report the nuclear magnetic resonance (NMR)-based metabolic profiling of field-grown leaves for a subset of sugar beet genotypes harbouring different levels of CLS resistance. Leaves were collected from 12 sugar beet genotypes at four time points: seedling, early growth, root enlargement, and disease development stages. 1H-NMR spectra of foliar metabolites soluble in a deuterium-oxide (D2O)-based buffer were acquired and subjected to multivariate analyses. A principal component analysis (PCA) of the NMR data from the sugar beet leaves shows clear differences among the growth stages. At the later time points, the sugar and glycine betaine contents were increased, whereas the choline content was decreased. The relationship between the foliar metabolite profiles and resistance level to CLS was examined by combining partial least squares projection to latent structure (PLS) or orthogonal PLS (OPLS) analysis and univariate analyses. It was difficult to build a robust model for predicting precisely the disease severity indices (DSIs) of each genotype; however, GABA and Gln differentiated susceptible genotypes (genotypes with weak resistance) from resistant genotypes (genotypes with resistance greater than a moderate level) before inoculation tests. The results suggested that breeders might exclude susceptible genotypes from breeding programs based on foliar metabolites profiled without inoculation tests, which require an enormous amount of time and effort.

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Section: Introductionmentioning

confidence: 99%

NMR-Based Metabolic Profiling of Field-Grown Leaves from Sugar Beet Plants Harbouring Different Levels of Resistance to Cercospora Leaf Spot Disease

et al. 2017

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“…Monitoring can support region-specific variety choice and management strategies aimed at reducing the overall CLS population and the frequency of virulent strains. These management strategies will likely utilize an integrated plant protection approach that combines precise timing of fungicide applications with agronomic practices such as crop rotation and tillage to reduce the buildup of inoculum in the soil (Harveson et al, 2009; Khan et al, 2008; Khan and Khan, 2010; Secor et al, 2010) (Khan et al, 2008; Khan and Khan, 2010; Jacobsen and Franc, 2007; Secor et al 2010 ). Varieties that combine BvCR4 with other sources of resistance can provide a strong CLS background resistance that will further contribute to a reduction of the CLS population and increase the durability of BvCR4 .…”

Section: Discussionmentioning

confidence: 99%

Genome-wide association studies reveal a rapidly evolving candidate avirulence effector in the Cercospora leaf spot pathogenCercospora beticola

Chen

Keunecke

Bemm

et al. 2023

Preprint

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The major resistance gene BvCR4 recently bred into sugar beets provides a high level of resistance to Cercospora leaf spot caused by the fungal pathogen Cercospora beticola. The occurrence of pathogen strains virulent to BvCR4 was studied using field trials in Switzerland and Germany. Virulence of a subset of these strains was tested in a field trial conducted under elevated artificial disease pressure. We created a new C. beticola reference genome and mapped whole genome sequences of 256 field-collected isolates and combined this with the virulence phenotypes to conduct three separate GWAS to identify candidate avirulence genes. GWAS analyses identified a locus associated with avirulence containing a single candidate avirulence effector gene named AvrCR4. All virulent isolates either lacked AvrCR4 or had non-synonymous mutations within the gene. AvrCR4 was present in all 74 unique isolates obtained from non-BvCR4 hybrids, whereas 33 of 89 unique isolates obtained from BvCR4 hybrids carried this deletion. We also mapped genomic data from 190 publicly available isolates from the U.S to our new reference genome. The AvrCR4 deletion was found in only one of 95 unique isolates from non-BvCR4 hybrids in the U.S. AvrCR4 presents a unique example of an avirulence effector in which virulent alleles have only recently emerged. Most likely these were selected out of the standing genetic variation after deployment of a new major resistance gene. Identification of AvrCR4 will enable real-time screening of C. beticola populations for the emergence and spread of virulent isolates as well as long-term studies of effector evolution.

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Occurrence of Cercospora beticola Sacc populations resistant to benzimidazole, demethylation-inhibiting, and quinone outside inhibitors fungicides in Morocco

et al. 2022

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Sugar Beet Diseases: Cercospora Leaf Spot

Cited by 5 publications

References 17 publications

NMR-Based Metabolic Profiling of Field-Grown Leaves from Sugar Beet Plants Harbouring Different Levels of Resistance to Cercospora Leaf Spot Disease

NMR-Based Metabolic Profiling of Field-Grown Leaves from Sugar Beet Plants Harbouring Different Levels of Resistance to Cercospora Leaf Spot Disease

Genome-wide association studies reveal a rapidly evolving candidate avirulence effector in the Cercospora leaf spot pathogenCercospora beticola

Occurrence of Cercospora beticola Sacc populations resistant to benzimidazole, demethylation-inhibiting, and quinone outside inhibitors fungicides in Morocco

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