Rapid adaptation of signaling networks in the fungal pathogen Magnaporthe oryzae

The link between changing in host carbon allocation and resistance to Magnaporthe oryzae: a possible tactic for mitigating the rice blast fungus

One of the most destructive diseases affecting rice is rice blast, which is brought on by the rice blast fungus Magnaporthe oryzae. The preventive measures, however, are not well established. To effectively reduce the negative effects of rice blasts on crop yields, it is imperative to comprehend the dynamic interactions between pathogen resistance and patterns of host carbon allocation. This review explores the relationship between variations in carbon allocation and rice plants' ability to withstand the damaging effects of M. oryzae. The review highlights potential strategies for altering host carbon allocation including transgenic, selective breeding, crop rotation, and nutrient management practices as a promising avenue for enhancing rice blast resistance. This study advances our knowledge of the interaction between plants' carbon allocation and M. oryzae resistance and provides stakeholders and farmers with practical guidance on mitigating the adverse effects of the rice blast globally. This information may be used in the future to create varieties that are resistant to M. oryzae.

Data-Independent Acquisition (DIA) Is Superior for High Precision Phospho-Peptide Quantification in Magnaporthe oryzae

The dynamic interplay of signaling networks in most major cellular processes is characterized by the orchestration of reversible protein phosphorylation. Consequently, analytic methods such as quantitative phospho-peptidomics have been pushed forward from a highly specialized edge-technique to a powerful and versatile platform for comprehensively analyzing the phosphorylation profile of living organisms. Despite enormous progress in instrumentation and bioinformatics, a high number of missing values caused by the experimental procedure remains a major problem, due to either a random phospho-peptide enrichment selectivity or borderline signal intensities, which both cause the exclusion for fragmentation using the commonly applied data dependent acquisition (DDA) mode. Consequently, an incomplete dataset reduces confidence in the subsequent statistical bioinformatic processing. Here, we successfully applied data independent acquisition (DIA) by using the filamentous fungus Magnaporthe oryzae as a model organism, and could prove that while maintaining data quality (such as phosphosite and peptide sequence confidence), the data completeness increases dramatically. Since the method presented here reduces the LC-MS/MS analysis from 3 h to 1 h and increases the number of phosphosites identified up to 10-fold in contrast to published studies in Magnaporthe oryzae, we provide a refined methodology and a sophisticated resource for investigation of signaling processes in filamentous fungi.

Magnaporthe oryzae as an expression host for the production of the unspecific peroxygenase AaeUPO from the basidiomycete Agrocybe aegerita

The filamentous fungus Magnaporthe oryzae has the potential to be developed as an alternative platform organism for the heterologous production of industrially important enzymes. M. oryzae is easy to handle, fast-growing and unlike yeast, posttranslational modifications like N-glycosylations are similar to the human organism. Here, we established M. oryzae as a host for the expression of the unspecific peroxygenase from the basidiomycete Agrocybe aegerita (AaeUPO). Note, UPOs are attractive biocatalysts for selective oxyfunctionalization of non-activated carbon-hydrogen bonds. To improve and simplify the isolation of AaeUPO in M. oryzae, we fused a Magnaporthe signal peptide for protein secretion and set it under control of the strong EF1α-promoter. The success of the heterologous production of full-length AaeUPO in M. oryzae and the secretion of the functional enzyme was confirmed by a peroxygenase-specific enzyme assay. These results offer the possibility to establish the filamentous ascomycete M. oryzae as a broad applicable alternative expression system.

The Determination of Carbohydrates by High-Performance Anion-Exchange Chromatography Coupled with Pulsed Amperometric Detection (HPAEC-PAD)

Chromatography techniques are widely used to separate, identify, and quantify molecules depending on their physicochemical properties. Standard methods range from simple size exclusion to separation based on affinity or ion exchange. Here, we present a method for the direct analysis of carbohydrates in Magnaporthe oryzae using high-performance anion-exchange chromatography (HPAEC) coupled with pulsed amperometric detection (PAD). The combination of HPAEC with PAD provides the highest selectivity and sensitivity with minimal sample preparation and cleanup time. Utilizing our HPAEC-PAD approach, we obtain reliable and highly reproducible determination of carbohydrates produced as osmotic stress response by M. oryzae. Thus, the method described provides a fast, precise, and comprehensive analysis of stress-dependent metabolic adjustments of carbohydrates not only relevant for M. oryzae but also applicable in other systems.

Making Visualization Work for You: Deriving Valuable Insights from Omics Data

"Omics" technologies (genomics, transcriptomics, proteomics, metabolomics, etc.) have significantly improved our understanding of biological systems. They have become standard tools in biological research, for example, identifying and unraveling transcriptional networks, building predictive models, and discovering candidate biomarkers. The rapid increase of omics data presents both a challenge and great potential when it comes to providing valuable insights into the underlying patterns of the investigated biological processes. The challenge is extracting, processing, integrating, and interpreting the corresponding datasets. The potential, on the other hand, arises from generation of verifiable hypotheses to understand molecular mechanisms behind biological processes, for example, gene expression patterns. Exploratory data analysis techniques are used to get a first impression of the important characteristics of a dataset and to reveal its underlying structure. However, investigators are often faced with the difficulties of managing the high-dimensional nature of the data. In order to efficiently analyze biological data and to gain a deeper understanding of underlying biological mechanisms, it is essential to have robust and interactive data visualization tools.

The Molecular Mechanism of Fludioxonil Action Is Different to Osmotic Stress Sensing

The group III two-component hybrid histidine kinase MoHik1p in the filamentous fungus Magnaporthe oryzae is known to be a sensor for external osmotic stress and essential for the fungicidal activity of the phenylpyrrole fludioxonil. The mode of action of fludioxonil has not yet been completely clarified but rather assumed to hyperactivate the high osmolarity glycerol (HOG) signaling pathway. To date, not much is known about the detailed molecular mechanism of how osmotic stress is detected or fungicidal activity is initiated within the HOG pathway. The molecular mechanism of signaling was studied using a mutant strain in which the HisKA signaling domain was modified by an amino acid change of histidine H736 to alanine A736. We found that MoHik1p^H736A is as resistant to fludioxonil but not as sensitive to osmotic stress as the null mutant ∆Mohik1. H736 is required for fludioxonil action but is not essential for sensing sorbitol stress. Consequently, this report provides evidence of the difference in the molecular mechanism of fludioxonil action and the perception of osmotic stress. This is an excellent basis to understand the successful phenylpyrrole-fungicides’ mode of action better and will give new ideas to decipher cellular signaling mechanisms.

Controllable Bypass Suppression in Magnaporthe oryzae

Evolutionary adaptation of living organisms is commonly thought to be the result of processes that have taken place over long periods of time. By contrast, we found that the filamentous rice blast fungus Magnaporthe oryzae rapidly suppresses the osmosensitive "loss of function" (lof) phenotype in knockout mutants of the high-osmolarity glycerol (HOG) pathway. That suppression occurs highly reproducibly after 4 weeks of continuous growth upon salt stress. Stable mutants reestablished in osmoregulation arise independently out of individual osmosensitive lof mutants of the HOG pathway. The major compatible solute produced upon salt stress by these suppressor strains was found to be glycerol, whereas it is arabitol in the wildtype strain. We aim to address the molecular or biochemical mechanisms behind this rapid suppression and characterize the associated factors and signaling pathways which enable or prevent suppression. Therefore, we present a protocol to generate these suppressor mutants in M. oryzae easily to study the molecular basis of evolutionary processes or even epigenetic modulation. This protocol may be applicable to many other fungi and will open a door for researchers worldwide since the HOG pathway is worked on intensively in many different model organisms.