Biology subjects

Schurack, S.

Publications and source records attributed to Schurack, S..

3 recordsLinked to original sources

bioRxiv2025

Partial cross-resistance of oats to different Fusarium species and the role of trichomes in susceptibility

Resistance of oats to FHB, caused by different Fusarium species, is important for grain quality and yield. In this study, 25 oat genotypes were evaluated for resistance to Fusarium graminearum (FG), F. sporotrichioides (FS) and F. poae (FP) in field trials across Germany to assess the presence of cross-resistance and to analyse the role of trichomes on the hulls during Fusarium infection. Infection severity was quantified by Fusarium species-specific qPCR and showed the highest fungal biomass for FP, followed by FS and FG. Variability due to environmental effects was very high, resulting in rather low heritabilities for FG (0.50) and FS (0.36), and no significant genotype effect for FP. A significant positive correlation was found between FP and FS infection, whereas FG infection was not correlated with either FP or FS. Microscopic analyses revealed important genotype-specific differences in trichome size and density on lemma and palea with very high heritability (0.97). FG biomass was positively correlated with trichome size and density, and FG hyphae were observed in close interaction with trichomes and stomata. These results indicate the presence of partial cross-resistance in addition to mostly species-specific resistance and suggest a role for trichomes in susceptibility to FG.

plant biology↗

bioRxiv2024

Genetic mapping of the powdery mildew resistance gene Pm13 on oat chromosome 1D

Powdery mildew, caused by the biotrophic fungus Blumeria graminis DC. f. sp. avenae, is a widespread disease of oats, especially in the temperate regions of Western and Central Europe, and the use of resistant varieties is the most sustainable way to ensure stable yields. Therefore, the identification of robust and effective resistance to powdery mildew is of great interest for oat breeding. In contrast to race-specific resistance genes, adult plant resistance (APR) is generally considered to be more durable. The oat variety Firth, as well as related varieties such as Husky or Flamingstip, contains an unknown APR gene, which was previously located on chromosome 1D using DArT markers. The aim of this study was to confirm and refine the chromosomal location of this resistance gene, tentatively named Pm13. To this end, two independent experiments were carried out using different genetic material under natural infection conditions in the field: genome-wide association mapping (GWAS) in a diverse set of 250 oat lines grown in ten environments and QTL mapping in a HuskyxAVE1284 bi-parental population grown in three environments. Both approaches identified a QTL for powdery mildew resistance on the distal end of chromosome 1D in the hexaploid Sang oat genome. The locus explained up to 15 % of the phenotypic variance in GWAS and 64 % of the phenotypic variance in QTL mapping. Comparison of field data with results from laboratory leaf segment tests confirmed that Pm13 does indeed confer APR. The sequence information of the identified linked markers may allow the development of molecular markers useful for early selection of oat lines with high levels of APR.

plant biology↗

bioRxiv2020

Transcriptome analysis in the maize-Ustilago maydis interaction identifies maize-line-specific activity of fungal effectors

The biotrophic pathogen Ustilago maydis causes smut disease on maize (Zea mays) and induces the formation of tumours on all aerial parts of the plant. Unlike in other biotrophic interactions, no gene-for-gene interactions have been identified in the maize-U. maydis pathosystem. Thus, maize resistance to U. maydis is considered a polygenic, quantitative trait. Here, we study the molecular mechanisms of quantitative disease resistance (QDR) in maize, and how U. maydis interferes with its components. Based on quantitative scoring of disease symptoms in 26 maize lines, we performed an RNA-Seq analysis of six U. maydis-infected maize lines of highly distinct resistance levels. In accordance with the complex nature of QDR, the different maize lines showed specific responses of diverse cellular processes to U. maydis infection. On the pathogen side, our analysis identified 406 U. maydis genes being differentially expressed between maize lines, of which 102 encode predicted effector proteins. Based on this analysis, we generated U. maydis CRISPR/Cas9 knockout mutants for selected candidate effector sets. Infections of different maize lines with the fungal mutants and subsequent RNA-sequencing identified effectors with quantitative, maize-line-specific virulence functions, and revealed auxin-related processes as a possible target for one of them. Thus, we show that both transcriptional activity and virulence function of fungal effector genes are modified according to the infected maize line, providing new insights into the molecular mechanisms underlying QDR in the maize-U. maydis interaction.

plant biology↗