Biology subjects

Maurus, I.

Publications and source records attributed to Maurus, I..

3 recordsLinked to original sources

bioRxiv2025

The adapt-to-nutrient NRPS-like secondary metabolite gene cluster facilitates Verticillium dahliae adaptation to different nutrient environments

Filamentous fungi produce a wide range of secondary metabolites to adapt to changing environments. RNA sequencing revealed that nine biosynthetic gene clusters (BGCs) of the phytopathogenic Verticillium dahliae react to different nutrient environments. The adapt-to-nutrient NRPS-like (ANN) cluster contributes to antibacterial activity and developmental processes important for the early biotrophic life cycle, but is dispensable for virulence on tomato (Solanum lycopersicum). Transcription of the core biosynthetic enzyme-encoding ANN3 is highly induced in nutrient-poor environment. ANN3 is transcriptionally controlled by global and in-cluster transcription factors. ANN3 is activated by early colonisation transcription factors Som1 and Vta2, but repressed by Mtf1, which governs late stages of disease progression. The in-cluster transcription factor Ann1, which represses ANN3, is less stable in nutrient-poor environment or when V. dahliae encounters antagonists. Ann1 promotes resting structure formation but suppresses conidiation and antibacterial activity. Possible products of the ANN cluster were revealed by comparing metabolites extracted from ANN3 regulator mutants and from the bacterial-fungal interaction zone. Our findings revealed that V. dahliae perceives different nutrient environments and changes its survival strategy by differential expression of the ANN secondary metabolite gene cluster. Author summaryVerticillium dahliae is an economically significant phytopathogen that is widely distributed. The fungus adjusts and adapts its survival strategy according to the surrounding environment. Transcriptome data revealed that the core biosynthetic gene ANN3 of the adapt-to-nutrient NRPS-like (ANN) cluster is most expressed in nutrient-poor environments. The expression of ANN3 is governed by in-cluster repressor Ann1 and global transcriptional regulators that regulate other metabolic processes. Transcription factors Som1 and Vta2 are involved in the early plant-root infection process, whereas Mtf1 regulates late stage of disease development. ANN3 is activated by Som1 and Vta2, but repressed by Mtf1. The repressor Ann1 is less stable in nutrient-poor environments or when bacterial competitors are present. Ann1 promotes dormancy and represses spreading by conidiation. Vegetative growth is reduced but antibacterial activity is promoted when ANN1 is deleted. Possible chemical products of the ANN cluster were identified by comparing the metabolites extracted from the regulator mutant strains and the bacterial-fungal interaction zone. In summary, our findings show how V. dahliae react to environmental signals to balance growth, survival, and competition through the ANN cluster.

genetics↗

bioRxiv2020

V. longisporum elicits media-dependent secretome responses with a further capacity to distinguish between plant-related environments

Verticillia cause a vascular wilt disease affecting a broad range of economically valuable crops. The fungus enters its host plants through the roots and colonizes the vascular system. It requires extracellular proteins for a successful plant colonization. The exoproteome of the allodiploid Verticillium longisporum was analyzed upon cultivation in different media. Secreted fungal proteins were identified by label free LC-MS/MS screening. V. longisporum induced two main secretion patterns. One response pattern was elicited in various non-plant related environments. The second pattern includes the exoprotein responses to the plant-related media, pectin-rich simulated xylem medium and pure xylem sap, which exhibited similar but additional distinct features. These exoproteomes include a shared core set of 223 secreted and similarly enriched fungal proteins. The pectin-rich medium significantly induced the secretion of 144 proteins including a number of pectin degrading enzymes, whereas xylem sap triggered a smaller but unique fungal exoproteome pattern with 32 enriched proteins. The latter pattern included proteins with domains of known effectors, metallopeptidases and carbohydrate-active enzymes. The most abundant and uniquely enriched proteins of these different groups are the necrosis and ethylene inducing-like proteins Nlp2 and Nlp3, the cerato-platanin proteins Cp1 and Cp2, the metallopeptidases Mep1 and Mep2 and the CAZys Gla1, Amy1 and Cbd1. Deletion of the majority of the corresponding genes caused no phenotypic changes during ex planta growth or invasion and colonization of tomato plants. However, we discovered that the NLP2 and NLP3 deletion strains were compromised in plant infections. Overall, our exoproteome approach revealed that the fungus induces specific secretion responses in different environments. The fungus has a general response to non-plant related media whereas it is able to fine-tune its exoproteome in the presence of plant material. Importantly, the xylem sap-specific exoproteome pinpointed Nlp2 and Nlp3 as single effectors required for successful V. dahliae colonization. Author SummaryVerticillium spp. infect hundreds of different plants world-wide leading to enormous economic losses. Verticillium wilt is a disease of the vasculature. The fungus colonizes the xylem of its host plant where it exploits the vascular system to colonize the whole plant. Therefore, the fungus spends part of its lifetime in this nutrient-low and imbalanced environment where it is inaccessible for disease control treatments. This lifestyle as well requires the fungus to react to plant defense responses by secreting specific effector molecules to establish a successful infection. We addressed the differences in media-dependent secretion responses of Verticillium longisporum. We identified a broad response pattern induced by several media, and a similar response (but with some distinct differences) for the plant-related environments: the pectin-rich medium SXM and xylem sap from the host rapeseed. Importantly, we show that the necrosis and ethylene inducing-like proteins Nlp2 and Nlp3 are xylem sap-specific proteins that are required for full V. dahliae pathogenicity on tomato. These factors play a role during the colonization phase and represent potential targets for new control strategies for Verticillium wilt.

genetics↗

bioRxiv2020

Unfolded protein response and scaffold independent pheromone MAP kinase signalling control Verticillium dahliae growth, development and plant pathogenesis

O_LIDevelopment and virulence of the vascular plant pathogen Verticillium dahliae are connected and depend on a complex interplay between the unfolded protein response, a Ham5 independent pheromone MAP kinase module and formation of precursors for oxylipin signal molecules. C_LIO_LIGenes coding for the unfolded protein response regulator Hac1, the Ham5 MAPK scaffold protein, and the oleate {Delta}12-fatty acid desaturase Ode1 were deleted and their functions in growth, differentiation, and virulence on plants were studied using genetic, cell biology, and plant infection experiments. C_LIO_LIThe unfolded protein response transcription factor Hac1 is required for initial root colonization, fungal conidiation and propagation inside the host and is essential for resting structure formation. Microsclerotia development, growth and virulence require the pheromone response MAPK pathway, but without the Ham5 scaffold function. Single ER-associated enzymes for linoleic acid production make important contributions to fungal growth but have only a minor impact on the pathogenicity of V. dahliae. C_LIO_LIFungal growth, sporulation, dormant structure formation and plant infection require a network of the Hac1-regulated unfolded protein response, a scaffold-independent pheromone response MAPK pathway and formation of precursors for signalling. This network includes interesting targets for disease management of the vascular pathogen V. dahliae. C_LI

genetics↗