A A Colletotrichum graminicola Mutant Deficient in the Mutant Deficient in the Establishment of Biotrophy Reveals Early Transcriptional Events Establishment of Biotrophy Reveals Early Transcriptional Events in the Maize Anthracnose Disease Interaction in the Maize Anthracnose Disease Interaction
This approach revealed, in unprecedented detail, fungal genes specifically expressed during critical phases of host penetration and biotrophic establishment of C. graminicola.
It is shown that the understudied bZIP transcription factor PnAda1 is an important downstream component of this PnPf2-regulatory network, and current understanding of the transcriptional network underlying virulence, metabolism and stress adaptation in an important fungal wheat pathogen is expanded.
S. Morikawa, Leon Lenzo, Keshara Colomba Thanthrige et al.· bioRxiv· 0 citations
Clonostachys rosea has long been the primary model for studying mycoparasitism within its genus; however, the potential of other species remains largely unexplored. In this study, we established a PEG-CaCl2-mediated protoplast transformation system for Clonostachys reniana. Our results demonstrate for the first time that this species is amenable to genetic manipulation and produces transformants with genetic stability, providing a reliable platform for functional genomic research in this fungus. Using Green Fluorescent Protein (GFP) tagging, we achieved stable transformants that retained wild-type physiological traits. Crucially, our data indicated that C. reniana utilizes a distinct mycoparasitic mechanism, which differs from the well-established sequential process of adhesion, coiling, and lysis seen in C. rosea. Confocal and scanning electron microscopy (SEM) revealed that C. reniana, following initial coiling and invasive structure formation, penetrates the host hyphae of Botryosphaeria dothidea. It then grows longitudinally within the hyphal lumen, absorbing nutrients and eliminating the pathogen from the inside. Furthermore, C. reniana hyphae can colonize the intercellular spaces of the stem periderm in 84K poplar (Populus alba × P. glandulosa), while displaying a distinct tissue-specific behavior in the roots by forming a mantle on the root surface resembling that of ectomycorrhizae. These findings establish C. reniana as a highly promising secondary model species within the Clonostachys genus. By uncovering a novel "internal-consumption" mycoparasitic mode, this study expands our understanding of the ecological diversity of biocontrol fungi and provides a powerful genetic toolset for future functional genomic research.
Shuang Zhou, Xuesong Wang, Yan Ma et al.· Phytopathology· 0 citations
Phytophthora species cause many devastating diseases of plants, including those of forest trees. Agathis australis (New Zealand kauri) is an ancient and culturally significant tree species that is susceptible to a lethal root and collar rot caused by Phytophthora agathidicida. Functional characterisation of P. agathidicida virulence factors is limited by difficulties in working with its natural host. The angiosperm Nicotiana benthamiana is widely used as a model plant host for studying plant-pathogen interactions, including P. agathidicida. To help determine whether N. benthamiana is a reliable model for the gymnosperm A. australis, we analysed P. agathidicida gene expression in leaves and roots of N. benthamiana and compared this to an earlier transcriptomic analysis in A. australis. A core set of 1129 genes upregulated in both hosts and organs was enriched for secreted RXLR effector, CAZyme and elicitin proteins, indicating a conserved infection-associated transcriptional programme. Similarities between the suites of genes expressed in leaves and roots support the approach of performing assays of gene function on leaves which are technically easier to use than roots. While many genes were similarly expressed across hosts, there were also some differences. A CAP protein, highly expressed only in N. benthamiana, increased P. agathidicida growth in N. benthamiana but not in A. australis under the conditions tested. These findings suggest that P. agathidicida deploys a largely conserved molecular strategy to colonise gymnosperm and angiosperm hosts, supporting the use of N. benthamiana as a model system for functional studies, while also highlighting pathogen genes that are highly expressed and upregulated in each of the hosts.
Rosie E. Bradshaw, J. Shiller, Yanan Guo et al.· Fungal Biology· 0 citations
It is revealed that CfMBZ1 plays a critical role in the pathogenesis of Glomerella leaf spot caused by C. fructicola and regulates appressorium-mediated penetration by modulating genes involved in peroxisome biogenesis, lipid droplet metabolism, and other penetration-related pathways.
Wenkui Liu, Wenxin Shi, Yecan Pan et al.· Phytopathology Research· 0 citations
Wheat Fusarium head blight (FHB) is a globally prevalent and destructive fungal disease predominantly caused by Fusarium graminearum. Pydiflumetofen, a novel succinate dehydrogenase inhibitor (SDHI) fungicide, exhibits strong inhibitory activity against F. graminearum; however, the molecular regulatory mechanisms underlying the field-developed resistance in this pathogen remain poorly defined. In the present study, a field-evolved resistant isolate W24-039 and a sensitive isolate W24-016 were subjected to multi-omics analysis. The sequencing results identified compound mutations C89S/A93V in SdhC2, and A21T/S30F in SdhD of the resistant strain, which confer stable fungicide resistance without any detectable fitness costs. Physiological tests revealed that these target mutations sustain the homeostasis of succinate dehydrogenase (SDH) activity and intracellular ATP production. Following pydiflumetofen treatment, the sensitive isolate displayed remarkable declines in SDH activity, intracellular ATP content and deoxynivalenol (DON) biosynthesis, accompanied by markedly elevated cell membrane permeability. Transcriptomic sequencing uncovered 2221 differentially expressed genes (DEGs) in the sensitive strain under fungicide stress, and 2566 DEGs in the resistant isolate under the same conditions. The genes associated with detoxification and drug efflux, including cytochrome P450, glutathione S-transferase (GST), ABC and MFS transporters, were significantly upregulated in the resistant isolate. Metabolomic analysis indicated that differential metabolites were mainly enriched in the tricarboxylic acid (TCA) cycle, amino acid metabolism and membrane lipid biosynthesis pathways. The resistant strain maintained intact TCA cycle operation and accumulated high levels of pivotal metabolites such as phosphatidylcholine, unsaturated fatty acids and reduced glutathione. Integrated multi-omics analysis verified that the ABC transporter and glutathione metabolism pathways serve as core regulatory modules governing fungicide resistance. Collectively, F. graminearum develops resistance via the synergistic effects of SDH compound mutations, enhanced detoxification and efflux, and global metabolic remodeling, demonstrating that target-site mutation alone is not the sole driver of resistance, which is instead controlled by an intricate regulatory network involving multiple coordinated pathways. This study systematically characterizes the resistance regulatory network of F. graminearum against pydiflumetofen, and provides theoretical guidance for the rational application and sustainable field resistance management of this fungicide.
Yun Wang, Dongmei Liu, Haiyan Yin et al.· International Journal of Mol...· 0 citations
The brown planthopper, Nilaparvata lugens, is a major rice pest causing significant yield losses across Asia. Concerns over the environmental, health, and resistance-related impacts of current chemical control strategies highlight the need for sustainable alternatives. In this study, we isolated and characterized a novel entomopathogenic fungus, strain NLS-1, from mycosed N. lugens cadavers. Based on morphological observations and internal transcribed spacer (ITS) sequence analysis, strain NLS-1 was assigned to Aspergillus section Flavi and designated as Aspergillus sp. NLS-1. Bioassays revealed that the isolate exhibited high virulence against third-instar N. lugens nymphs; the highest concentration of 1 × 108 conidia/mL resulted in 97.22% corrected mortality by 9 days post-inoculation and a median lethal time (LT50) of 4.13 days. Scanning electron microscopy delineated the infection process, confirming firm conidial adhesion to the cuticle, followed by germination, hyphal proliferation, and eventual host colonization. Furthermore, fungal infection significantly altered the nymphs' bacterial community structure, notably affecting the relative abundances of Acinetobacter and Serratia. These findings position Aspergillus sp. NLS-1 as a promising biocontrol agent and suggest that its pathogenicity may be mediated through the disruption of the host's microbiota, providing new insights for the integrated management of N. lugens.
H. Niu, Sai-Ge Sun, Zhi-Chun Zhang et al.· Journal of Invertebrate Path...· 0 citations
