Biology subjects

Douchkov, D.

Publications and source records attributed to Douchkov, D..

5 recordsLinked to original sources

bioRxiv2025

Transcriptome analysis of the response of domesticated emmer wheat (Triticum turgidum subsp. dicoccum) to single vs. mixed infections with Zymosptoria tritici and Puccinia graminis

Tetraploid emmer Triticum turgidum subsp. dicoccum is one of the first wheat species to be domesticated. Emmer shares many pathogen species with modern durum wheat (Triticum turgidum subsp. durum) and hexaploid bread wheat (Triticum aestivum L.). Domesticated emmer is considered a highly valuable source of potentially novel disease resistance genes that can be introduced into modern wheat varieties, however, large gaps remain in our understanding of the basic immune responses of emmer to the most common wheat pathogens. In this work we describe the transcriptional response of emmer to single and mixed pathogen species infections with the ascomycete Zymoseptoria tritici, and the basidiomycete Puccinia graminis. In doing so, we here uncover unique patterns in the response of emmer to a more complex pathogen population with mixed species infections.

plant biology↗

bioRxiv2024

An experimental approach to study multi-species diseases interactions in wheat using machine learning-aided image analysis

Fusarium Head Blight (FHB) is a major disease of cereal crops present everywhere where wheat is produced. A complex of several, distinctly different, species from the genus Fusarium are responsible for causing the disease, with important taxa being F. graminearum, F. culmorum, and F. avenaceum. FHB is an adult stage, late season disease affecting wheat at anthesis. However, recent discoveries are now challenging the basic assumption that anthers and spikes are the only ecological niches relevant for resistance to FHB. Most prominently, it has been established that pathogens typically occurring earlier in the season, such as Zymoseptoria tritici, induce strong systemic changes in the plant immune system, that expand way beyond their primary ecological niche. Furthermore, taxa implicated in FHB can be isolated from virtually all wheat tissues, including typical blotch symptoms on wheat leaves. Strikingly, such important biological observations about the complex lifestyle of FHB causing taxa are overlooked as potential targets in resistance breeding. In this work we present a simplified approach allowing the dissection of the intricate lifestyles of the FHB causing Fusarium taxa. In doing so, we provide an experimental proof-of-concept that systemic signals from Z. tritici can affect the basic response of wheat to F. graminearum. We further demonstrate that differences in Fusarium species composition affect the outcome of the interaction in a genotype-specific manner. We argue that efforts to study hidden layers of the biology of FHB associated taxa are crucial to developing new resistance breeding strategies, based on a better understanding of the genetic drivers of the disease.

plant biology↗

bioRxiv2024

Survey of the wheat mycobiome associated with leaf blotch and head blight diseases in Sweden

Increasing the durability of crop resistance to plant pathogens has become a major concern in plant pathology. There are 32 diseases of agronomical importance in wheat, which makes disease management in this crop of worldwide importance extremely challenging. Two important groups of wheat pathogens driving the consumption of chemical fungicides in Sweden and worldwide are those causing head blight diseases and leaf blotch diseases. Swedish fields are regularly infested with head blight diseases typically driven by a complex of Fusarium and non-fusarium taxa including F. graminearum, F. culmorum, while leaf blotches are typically caused by Zymoseptoria tritici, Pyrenophora tritici-repentis, and Parastagonospora nodorum. In this work, we present a survey of the larger diversity of taxa associated with head blight and leaf blotch diseases in Sweden, with the primary aim to assess the usefulness of such an approach to develop new understanding and tools for disease diagnostics and management sensu lato. Here, we analyze nearly a thousand isolates collected from wheat fields across eight counties in Sweden and report the identification of pathogenic and non-pathogenic taxa as well as candidate biological control agents associated with head blight and leaf blotch diseases. We argue that such surveys represent an important tool for improving disease diagnostics, disease forecasting, and integrated management in wheat.

plant biology↗

bioRxiv2020

'Macrobot' - an automated segmentation-based system for powdery mildew disease quantification

Plant diseases, as one of the perpetual problems in agriculture, is increasingly difficult to manage due to intensifying of the field production, global trafficking, reduction of genetic variability of crops, climatic changes-driven expansion of pests, redraw and loss of effectiveness of pesticides and rapid breakdown of the disease resistance in the field. The substantial progress in genomics of both plants and pathogens, achieved in the last decades has the potential to counteract this negative trend, however, only when the genomic data is supported by relevant phenotypic data that allows linking the genomic information to specific traits. In this respect, phenotyping is and will remain an essential element of any comprehensive functional genomics study. We have developed a set of methods and equipment and combined them into a "Macrophenomics pipeline". The pipeline has been optimized for the quantification of powdery mildew infection symptoms on wheat and barley but it can be adapted to other diseases and host plants. The Macrophenomics pipeline scores the visible disease symptoms, typically 5-7 days after inoculation (dai) in a highly automated manner. The system can precisely and reproducibly quantify the percentage of the infected leaf area with a throughput of the image acquisition module of up to 10 000 individual samples per day, making it appropriate for phenotyping of large germplasms collections and crossing populations.

plant biology↗

bioRxiv2017

The partial duplication of an E3-ligase gene in Triticeaespecies mediates resistance to powdery mildew fungi

In plant-pathogen interactions, components of the plant ubiquitination machinery are preferred targets of pathogen-encoded effectors suppressing defense responses or co-opting host cellular functions for accommodation. Here, we employed transient and stable gene silencing-and over-expression systems in Hordeum vulgare (barley) to study the function of HvARM1 (for H. vulgare Armadillo 1), a partial gene duplicate of the U-box/armadillo-repeat E3 ligase HvPUB15 (for H. vulgare Plant U-Box 15). The partial ARM1 gene was derived from an ancient gene-duplication event in a common ancestor of the Triticeae tribe of grasses comprising the major crop species H. vulgare, Triticum aestivum and Secale cereale. The barley gene HvARM1 contributed to quantitative host as well as nonhost resistance to the biotrophic powdery mildew fungus Blumeria graminis, and allelic variants were found to be associated with powdery mildew-disease severity. Both HvPUB15 and HvARM1 proteins interacted in yeast and plant cells with the susceptibility-related, plastid-localized barley homologs of THF1 (for Thylakoid formation 1) and of ClpS1 (for Clp-protease adaptor S1) of Arabidopsis thaliana. The results suggest a neo-functionalization HvARM1 to increase resistance against powdery mildew and provide a link to plastid function in susceptibility to biotrophic pathogen attack.

plant biology↗