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Background: Cell wall integrity (CWI) is crucial for fungal growth, pathogenesis, and adaptation to extracellular environments. Calcofluor white (CFW) is a cell wall perturbant that inhibits fungal growth, yet little is known about how phytopathogenic fungi respond to the CFW-induced stress. Results: In this study, we unveiled a significant discovery that CFW triggered the translocation of the transcription factor CgCrzA from the cytoplasm to the nucleus in Colletotrichum gloeosporioides. This translocation was regulated by an interacting protein, CgMkk1, a mitogen-activated protein kinase involved in the CWI pathway. Further analysis revealed that CgMkk1 facilitated nuclear translocation by phosphorylating CgCrzA at the Ser280 residue. Using chromatin immunoprecipitation sequencing, we identified two downstream targets of CgCrzA, namely CgCHS5 and CgCHS6, which are critical for growth, cell wall integrity, and pathogenicity as chitin synthase genes. Conclusions: These findings provide a novel insight into the regulatory mechanism of CgMkk1-CgCrzA-CgChs5/6, which enables response of the cell wall inhibitor CFW and facilitates infectious growth for C. gloeosporioides. [ABSTRACT FROM AUTHOR]

Cordyceps militaris is one of the commercially cultivated mushrooms, valued for its medicinal and nutritional benefits. However, the fruiting body development mechanism has remained elusive. Chitin synthases (CHSs) are ubiquitous enzymes involved in the regulation of fungal growth, development and virulence. In this study, a total of eight CmChs genes were identified. Chromosomal localization analysis revealed an uneven distribution of CmCHSs across the C. militaris genome. Based on the phylogenetic analysis, 100 CHSs from Cordyceps sensu lato, encompassing C. militaris, were categorized into three divisions and seven classes, shedding light on their evolutionary relationships. There was no significant difference in the number of CHSs between ascomycetes and basidiomycetes in general (p = 0.067), as well as between pathogenic and saprotrophic fungi in general (p = 0.151 and 0.971 in Ascomycota and Basidiomycota fungi, respectively). This underscored the essential and conserved nature of these CHSs across various fungal lifestyles and ecological niches. The different transcript patterns of the eight CmChss during key life cycle stages, such as conidia germination, infection, and fruiting body development, indicated that each CHS gene may have a distinct role during specific stages of the life cycle. In conclusion, these findings indeed lay the groundwork for a further exploration of the functional roles of CHSs in the regulatory mechanism of fruiting body development in C. militaris. [ABSTRACT FROM AUTHOR]

Abstract Background Aedes albopictus is a vector of numerous devastating arboviruses and places heavy burdens on global public health. Chitin is one of the important components of cuticles and targeting chitin metabolism is a promising strategy for preventing mosquito dispersal and mosquito-borne diseases. Increasing evidence suggests that microRNAs (miRNAs) play crucial roles in various physiological processes of insects. Methods A previous analysis suggested that the microRNA miR-989 is potentially involved in chitin metabolism in Ae. albopictus pupae. In the present study, we found that the expression level of miR-989 was significantly overexpressed after injection of agomir. A dual-luciferase assay was used to determine the direct target of miR-989. Survival rate, eclosion rate and malformation rate were statistically analyzed to evaluate the potential effect of miR-989. Hematoxylin–eosin staining and chitin staining were used to evaluate the microstructural changes in the cuticles of Ae. albopictus pupae. Results Overexpression of miR-989 resulted in a significantly reduced survival rate and eclosion rate of pupae and an elevated malformation rate of adults. The results suggested that miR-989 acted as a regulator of chitin metabolism in Ae. albopictus pupae by affecting the transcript levels of the Ae. albopictus genes encoding chitin synthase 1 (AaCHS1) and chitinase 10 (AaCht10). The altered expression levels of the two chitin metabolism-related enzymes (CHS1 and Cht10, respectively) caused the structural changes in cuticles and further affected the pupal-adult transition process of Ae. albopictus. XM_029863591.1 was proven to be the target gene of miR-989 and displayed similar effects on pupae as miR-989. Conclusions The microRNA miR-989 was found to be essential for chitin metabolism in old and new cuticles of Ae. albopictus pupae. The results of the current study suggested that miR-989 could be used as a potential target to control Ae. albopictus. Graphical Abstract

Background: Aedes albopictus is a vector of numerous devastating arboviruses and places heavy burdens on global public health. Chitin is one of the important components of cuticles and targeting chitin metabolism is a promising strategy for preventing mosquito dispersal and mosquito-borne diseases. Increasing evidence suggests that microRNAs (miRNAs) play crucial roles in various physiological processes of insects. Methods: A previous analysis suggested that the microRNA miR-989 is potentially involved in chitin metabolism in Ae. albopictus pupae. In the present study, we found that the expression level of miR-989 was significantly overexpressed after injection of agomir. A dual-luciferase assay was used to determine the direct target of miR-989. Survival rate, eclosion rate and malformation rate were statistically analyzed to evaluate the potential effect of miR-989. Hematoxylin–eosin staining and chitin staining were used to evaluate the microstructural changes in the cuticles of Ae. albopictus pupae. Results: Overexpression of miR-989 resulted in a significantly reduced survival rate and eclosion rate of pupae and an elevated malformation rate of adults. The results suggested that miR-989 acted as a regulator of chitin metabolism in Ae. albopictus pupae by affecting the transcript levels of the Ae. albopictus genes encoding chitin synthase 1 (AaCHS1) and chitinase 10 (AaCht10). The altered expression levels of the two chitin metabolism-related enzymes (CHS1 and Cht10, respectively) caused the structural changes in cuticles and further affected the pupal-adult transition process of Ae. albopictus. XM_029863591.1 was proven to be the target gene of miR-989 and displayed similar effects on pupae as miR-989. Conclusions: The microRNA miR-989 was found to be essential for chitin metabolism in old and new cuticles of Ae. albopictus pupae. The results of the current study suggested that miR-989 could be used as a potential target to control Ae. albopictus. [ABSTRACT FROM AUTHOR]

Cordyceps militaris is one of the commercially cultivated mushrooms, valued for its medicinal and nutritional benefits. However, the fruiting body development mechanism has remained elusive. Chitin synthases (CHSs) are ubiquitous enzymes involved in the regulation of fungal growth, development and virulence. In this study, a total of eight CmChs genes were identified. Chromosomal localization analysis revealed an uneven distribution of CmCHSs across the C. militaris genome. Based on the phylogenetic analysis, 100 CHSs from Cordyceps sensu lato, encompassing C. militaris, were categorized into three divisions and seven classes, shedding light on their evolutionary relationships. There was no significant difference in the number of CHSs between ascomycetes and basidiomycetes in general (p = 0.067), as well as between pathogenic and saprotrophic fungi in general (p = 0.151 and 0.971 in Ascomycota and Basidiomycota fungi, respectively). This underscored the essential and conserved nature of these CHSs across various fungal lifestyles and ecological niches. The different transcript patterns of the eight CmChss during key life cycle stages, such as conidia germination, infection, and fruiting body development, indicated that each CHS gene may have a distinct role during specific stages of the life cycle. In conclusion, these findings indeed lay the groundwork for a further exploration of the functional roles of CHSs in the regulatory mechanism of fruiting body development in C. militaris.

The glycogen synthase kinase-3 (GSK3) orthologs are well-conserved in eukaryotic organisms. However, their functions remain poorly characterized in filamentous fungi. In our previous study, we unveiled the function of Fgk3, the GSK3 ortholog, in glycogen metabolism in Fusarium graminearum , the causal agent of Fusarium head blight. Interestingly, the fgk3 mutant was unstable and tended to produce fast-growing suppressors, including secondary suppressors. Using whole-genome sequencing, we identified suppressor mutations in FgCHS5 , FgFKS1 , FgCREA , FgSSN6 , FgRGR1 , and FgPP2A in nine primary and four secondary suppressors. Subsequently, we validated that deletion of FgCHS5 or FgCREA ΔH253 mutation partially suppressed the defects of fgk3 in vegetative growth and cell wall integrity, suggesting that Fgk3 may regulate the chitin synthesis through FgCreA-mediated transcriptional regulation in F. graminearum . Accordingly, the FGK3 deletion led to hyphal swelling with abnormal chitin deposition, and deletion of FGK3 caused the upregulation of the expression of chitin synthases FgCREA caused the upregulation of the expression of chitin synthases FgCHS5 and FgCHS6 . The interaction between Fgk3 and FgCreA was verified by Yeast two-hybrid and Co-Immunoprecipitation assays. More importantly, we verified that the nuclear localization and protein stability of FgCreA relies on the Fgk3 kinase, while the H253 deletion facilitated the re-localization of FgCreA to the nucleus in the fgk3 mutant background, potentially contributing to the suppression of the fgk3 mutant's defects. Intriguingly, the ΔH253 mutation of FgCreA, identified in suppressor mutant S3, is adjacent to a conserved phosphorylation site, S254, suggesting that this mutation may inhibit the S254 phosphorylation and promote the nuclear localization of FgCreA. Collectively, our findings indicate that the glycogen synthase kinase Fgk3 regulates the chitin synthesis through the carbon catabolite repressor FgCreA in F. graminearum .

Fusarium fungi are the cause of an array of devastating diseases affecting yield losses and accumulating mycotoxins. Fungicides can be exploited against Fusarium and deoxynivalenol (DON) production. However, Fusarium resistance to common chemicals has become a therapeutic challenge worldwide, which indicates that new control agents carrying different mechanisms of action are desperately needed. Here, we found that a nonantibiotic drug, ethylenediaminetetraacetic acid disodium salt (EDTANa2), exhibited various antifungal activities against Fusarium species and DON biosynthesis. The infection of wheat seeding caused by F. graminearum was suppressed over 90% at 4 mM EDTANa2. A similar control effect was observed in field tests. Mycotoxin production assays showed DON production was significantly inhibited, 47% lower than the control, by 0.4 mM EDTANa2. In vitro experiments revealed a timely inhibition of H2O2 production as quickly as 4 h after amending cultures with EDTANa2 and the expression of several TRI genes significantly decreased. Chitin synthases of Fusarium were Mn2+-containing enzymes that were strongly inhibited by Mn2+ deficiency. EDTANa2 inhibited chitin synthesis and destroyed the cell wall and cytomembrane integrity of Fusarium, mainly via the chelation of Mn2+ by EDTANa2, and thus led to Mn deficiency in Fusarium cells. Taken together, these findings uncover the potential of EDTANa2 as a fungicide candidate to manage Fusarium head blight (FHB) and DON in agricultural production.

Complex networks have been successfully applied to the characterization and modeling of complex systems in several distinct areas of Biological Sciences. Nevertheless, their utilization in phylogenetic analysis still needs to be widely tested, using different molecular data sets and taxonomic groups, and, also, by comparing complex networks approach to current methods in phylogenetic analysis. In this work, we compare all the four main methods of phylogenetic analysis (distance, maximum parsimony, maximum likelihood, and Bayesian) with a complex networks method that has been used to provide a phylogenetic classification based on a large number of protein sequences as those related to the chitin metabolic pathway and ATP-synthase subunits. In order to perform a close comparison to these methods, we selected Basidiomycota fungi as the taxonomic group and used a high-quality, manually curated and characterized database of chitin synthase sequences. This enzymatic protein plays a key role in the synthesis of one of the exclusive features of the fungal cell wall: the presence of chitin. The communities (modules) detected by the complex network method corresponded exactly to the groups retrieved by the phylogenetic inference methods. Additionally, we propose a bootstrap method for the complex network approach. The statistical results we have obtained with this method were also close to those obtained using traditional bootstrap methods.

Complex networks have been successfully applied to the characterization and modeling of complex systems in several distinct areas of Biological Sciences. Nevertheless, their utilization in phylogenetic analysis still needs to be widely tested, using different molecular data sets and taxonomic groups, and, also, by comparing complex networks approach to current methods in phylogenetic analysis. In this work, we compare all the four main methods of phylogenetic analysis (distance, maximum parsimony, maximum likelihood, and Bayesian) with a complex networks method that has been used to provide a phylogenetic classification based on a large number of protein sequences as those related to the chitin metabolic pathway and ATP-synthase subunits. In order to perform a close comparison to these methods, we selected Basidiomycota fungi as the taxonomic group and used a high-quality, manually curated and characterized database of chitin synthase sequences. This enzymatic protein plays a key role in the synthesis of one of the exclusive features of the fungal cell wall: the presence of chitin. The communities (modules) detected by the complex network method corresponded exactly to the groups retrieved by the phylogenetic inference methods. Additionally, we propose a bootstrap method for the complex network approach. The statistical results we have obtained with this method were also close to those obtained using traditional bootstrap methods. [ABSTRACT FROM AUTHOR]

Chitin is one of the most abundant renewable resources, and chitosans, the partially deacetylated derivatives of chitin, are among the most promising functional biopolymers, with superior material properties and versatile biological functionalities. Elucidating molecular structure–function relationships and cellular modes of action of chitosans, however, it is challenging due to the micro-heterogeneity and structural complexity of polysaccharides. Lately, it has become apparent that many of the biological activities of chitosan polymers, such as in agricultural plant disease protection or in mediating scar-free wound healing, may be attributed to oligomeric break-down products generated by the action of chitosanolytic hydrolases present in the target tissues, such as human chitotriosidase. Consequently, the focus of current research is shifting toward chitosan oligomers so that the availability of well-defined chitosan oligosaccharides (COS) becomes a bottleneck. Well-known ways of producing COS use physical and/or chemical means for the partial depolymerization of chitosan polymers, typically leading to broad mixtures of COS varying in their degrees of polymerization (DP) and acetylation (DA), and with more or less random patterns of acetylation (PAs). Even after chromatographic separation according to DP and DA, such mixtures are of limited value to elucidate structure–function relationships and modes of action. More recently, enzymatic means using chitinases and/or chitosanases, and sometimes chitin deacetylases, have been proposed as these can be more tightly controlled and yield slightly better defined mixtures of COS. An alternative would be chemical synthesis of COS which in principle would allow for full structural control, but protocols for it are lengthy, costly, and not yet well developed, and yields are low. Synthetic biology now allows to develop today’sin vitrobio-refinery approaches intoin vivocell factory approaches for the biotechnological production of defined COS using recombinant microbial strains expressing chitin oligomer synthases and chitin oligomer deacetylases. In this review, we will describe the state-of-the-art of this cell factory approach, as a basis for upcoming developments. We will briefly describe traditional chemical protocols and enzymatic production of COS as a background to the more detailed presentation of what has been achieved through in vivo biosynthesis. We will only briefly describe those as a background to the more detailed presentation of what has been achieved throughin vivobiosynthesis. We will also touch on the production of COS derivatives that has been achieved in this way, as these oligomers open up another plethora of potential applications when used as building blocks for defined biomaterials. [ABSTRACT FROM AUTHOR]

Chitin is one of the most abundant biomaterials in nature. The biosynthesis and degradation of chitin in insects are complex and dynamically regulated to cope with insect growth and development. Chitin metabolism in insects is known to involve numerous enzymes, including chitin synthases (synthesis of chitin), chitin deacetylases (modification of chitin by deacetylation) and chitinases (degradation of chitin by hydrolysis). In this study, we conducted a genome-wide search and analysis of genes encoding these chitin metabolism enzymes in Manduca sexta . Our analysis confirmed that only two chitin synthases are present in M . sexta as in most other arthropods. Eleven chitin deacetylases (encoded by nine genes) were identified, with at least one representative in each of the five phylogenetic groups that have been described for chitin deacetylases to date. Eleven genes encoding for family 18 chitinases (GH18) were found in the M . sexta genome. Based on the presence of conserved sequence motifs in the catalytic sequences and phylogenetic relationships, two of the M . sexta chitinases did not cluster with any of the current eight phylogenetic groups of chitinases: two new groups were created (groups IX and X) and their characteristics are described. The result of the analysis of the Lepidoptera-specific chitinase-h (group h) is consistent with its proposed bacterial origin. By analyzing chitinases from fourteen species that belong to seven different phylogenetic groups, we reveal that the chitinase genes appear to have evolved sequentially in the arthropod lineage to achieve the current high level of diversity observed in M . sexta . Based on the sequence conservation of the catalytic domains and on their developmental stage- and tissue-specific expression, we propose putative functions for each group in each category of enzymes. [ABSTRACT FROM AUTHOR]

The cell wall defines the shape and provides osmotic stability to the yeast cell. It also serves to anchor proteins required for communication of the yeast cell with surrounding molecules and other cells. It is synthesized as a complex structure with β-1,3-glucan chains forming the basic network to which β-1,6-glucan, chitin and a number of mannoproteins are attached. Synthesis, maintaining and remodeling of this complex structure require a set of different synthases, hydrolases and transglycosidases whose concerted activities provide necessary firmness but at the same time flexibility of the wall moiety. The present state of comprehension of the interplay of these proteins in the yeast cell wall is the subject of this article. [ABSTRACT FROM AUTHOR]

Abstract: Chitin synthase (CHS) represents an attractive target site for combating insect pests as insect growth and development are strictly dependent on precisely tuned chitin biosynthesis and this pathway is absent in humans and other vertebrates. Current knowledge on CHS in insects, especially their structures, functions, and regulations is still very limited. We report the identification and characterization of two chitin synthase genes, AgCHS1 and AgCHS2, in African malaria mosquito, Anopheles gambiae. AgCHS1 and AgCHS2 were predicted to encode proteins of 1,578 and 1,586 amino acid residues, respectively. Their deduced amino acid sequences show high similarities to other insect chitin synthases. Transcriptional analysis indicated that AgCHS1 was expressed in egg, larval, pupal and adult stages whereas AgCHS2 appeared to be expressed at relatively low levels, particularly during the larval stages as examined by reverse transcription (RT)-PCR and real-time quantitative PCR. Relatively high expression was detected in the carcass followed by the foregut and hindgut for AgCHS1, and the foregut (cardia included) followed by the midgut for AgCHS2. Fluorescence in situ hybridization (FISH) and immunohistochemical analysis revealed new information including the localization of the two enzymes in the ommatidia of the compound eyes, and AgCHS2 in the thoracic and abdominal inter-segmental regions of pupal integument. [Copyright &y& Elsevier]

Abstract: Hyphal morphogenesis is largely determined by the mode the cell wall is synthesized. One of the main structural components of the cell wall is the chitin microfibril, whose synthesis is catalyzed at the cell surface by an organized but not fully understood complex of chitin-synthesizing enzymes. Genetic studies have identified several chitin synthase genes (chs) among different fungi. In each given species, several chitin synthases (CHS) may be present. These have been assigned to different classes (I–VII) on the basis of characteristic amino acid sequences. A revised phylogenetic scheme of fungal CHS is presented but there was no apparent correlation between CHS class and a specific cell function or cell cycle stage. The availability of methodology to make genetic fusions between CHS and green fluorescent protein (GFP) and to follow them in living cells with high-resolution confocal microscopy and widefield fluorescence microscopy has made it possible to study the location and dynamics of different CHS in several fungi. Among these, Neurospora crassa was recently used to analyse the spatial distribution and role of chitin synthases in hyphal tip growth. Here we summarise recent advances in this area with particular emphasis on N. crassa. CHS-3, CHS-6 and more recently CHS-1 are abundantly present in the distal regions of the hypha and contained in membranous structures of different shapes from spheres to elongated tubes; as the GFP–CHS tagged structures advance towards the tip, they begin to disintegrate. In the subapical region GFP–CHS was not found in large organelles; it only occurred as fine punctuate fluorescence. These minute structures are probably chitosomes. Finally, at the tip there is always a conspicuous accumulation of GFP–CHS in the Spitzenkörper core where microvesicles are known to accumulate. The collective evidence points to CHS travelling to its destination at the hyphal apex via a secretory route distinct from the conventional ER–Golgi route. The accumulation of CHS microvesicles at the Spk reinforces the view that this structure plays a pivotal role in cell wall growth and hyphal morphogenesis. [Copyright &y& Elsevier]

Chitin is a minor but essential component of the Saccharomyces cerevisiae cell wall. In wild-type, chitin synthase II is required for the formation of primary septa and chitin synthase III (CSIII) is not essential. However, in chs2 mutants CSIII becomes essential for the formation of aberrant septa. We examined which of two CSIII functions, the formation of a chitin ring at bud emergence or of chitin in the remedial septa, was required for viability. By using cell cycle synchronization in combination with nikkomycin Z, a specific inhibitor of CSIII, we inhibited chitin synthesis in a chs2 mutant, during formation of either the ring or the remedial septa. The results show that only synthesis of the chitin during aberrant septa formation is essential for viability. Thus, the unique function of the chitin ring seems to be maintenance of the integrity of the mother–bud neck, as we recently found, and the importance of chitin in septum closure, both in normal and abnormal situations, is underlined. [Copyright &y& Elsevier]

A straightforward and easy-to-apply semi-quantitative RT-PCR method was developed to study multigenic expression in the phytopathogenic fungus Botrytis cinerea. This procedure is based on the one-step reverse transcription-amplification of a specific transcript within total RNA and product amount determination by densitometric analysis of ethidium bromide fluorescence upon gel electrophoresis. The semi-quantitative analysis is achieved, at a fixed PCR cycle-number, within a range of total RNA concentrations that stays in the exponential phase of the PCR. Co-amplification of the transcript of interest with internal controls allowed comparison between different RNA samples. Using this method, we could demonstrate a differential regulation of chitin synthase genes during fungal growth and an effect of the culture carbon source on the expression of two pectin methylesterase genes in B. cinerea. Finally, the method was shown to be applicable to plant-infected tissue, making it a useful tool to detect pathogenicity genes in B. cinerea. [ABSTRACT FROM AUTHOR]

Chitin synthesis is a process maintained across the fungal kingdom that, thanks to the power of genetic manipulation of yeast cells, is now beginning to be understood. Chitin synthesis is based on the regulation of distinct chitin synthase isoenzymes whose number ranges from one in Schizosaccharomyces pombe to seven in some filamentous fungi, such as Aspergillus fumigatus. This high diversity makes it difficult to find a unique model of regulation. However, the results available suggest common themes in regulation. The arrival of the genomic era, together with the development of fungal genetic technology should allow experimental approaches to this process. [ABSTRACT FROM AUTHOR]

Here, we present a 231 Mb draft genome of the centric diatom Conticribra weissflogii CCMP1336. Comparative genomics of C. weissflogii and other Ochrophyta support the existence of unique carbon-concentrating mechanisms and chitin metabolic processes in diatoms. The whole-genome project is available at CNSA (https://db.cngb.org/search/project/CNP0001903/). [ABSTRACT FROM AUTHOR]

Fusarium fungi are the cause of an array of devastating diseases affecting yield losses and accumulating mycotoxins. Fungicides can be exploited against Fusarium and deoxynivalenol (DON) production. However, Fusarium resistance to common chemicals has become a therapeutic challenge worldwide, which indicates that new control agents carrying different mechanisms of action are desperately needed. Here, we found that a nonantibiotic drug, ethylenediaminetetraacetic acid disodium salt (EDTANa2), exhibited various antifungal activities against Fusarium species and DON biosynthesis. The infection of wheat seeding caused by F. graminearum was suppressed over 90% at 4 mM EDTANa2. A similar control effect was observed in field tests. Mycotoxin production assays showed DON production was significantly inhibited, 47% lower than the control, by 0.4 mM EDTANa2. In vitro experiments revealed a timely inhibition of H2O2 production as quickly as 4 h after amending cultures with EDTANa2 and the expression of several TRI genes significantly decreased. Chitin synthases of Fusarium were Mn2+-containing enzymes that were strongly inhibited by Mn2+ deficiency. EDTANa2 inhibited chitin synthesis and destroyed the cell wall and cytomembrane integrity of Fusarium, mainly via the chelation of Mn2+ by EDTANa2, and thus led to Mn deficiency in Fusarium cells. Taken together, these findings uncover the potential of EDTANa2 as a fungicide candidate to manage Fusarium head blight (FHB) and DON in agricultural production. [ABSTRACT FROM AUTHOR]

• Native chitin (Chs5) and glucan synthase (Gsc1) visualised in the pathogen Zymoseptoria tritici. • Chs5 and Gsc1 are transported along microtubules. • Chs5 and Gsc1 do localise to the apical plasma membrane, but not the Spitzenkörper. • Light and electron microscopy how co-travel of Chs5 and Gsc1 in the same secretory vesicle. • Enzyme delivery in Z. tritici is different from Neurospora crassa , but similar to Ustilago maydis. The fungal cell wall consists of proteins and polysaccharides, formed by the co-ordinated activity of enzymes, such as chitin or glucan synthases. These enzymes are delivered via secretory vesicles to the hyphal tip. In the ascomycete Neurospora crassa , chitin synthases and β(1,3)-glucan synthase are transported in different vesicles, whereas they co-travel along microtubules in the basidiomycete Ustilago maydis. This suggests fundamental differences in wall synthesis between taxa. Here, we visualize the class V chitin synthase ZtChs5 and the β(1,3)-glucan synthase ZtGcs1 in the ascomycete Zymoseptoria tritici. Live cell imaging demonstrate that both enzymes co-locate to the apical plasma membrane, but are not concentrated in the Spitzenkörper. Delivery involves co-transport along microtubules of the chitin and glucan synthase. Live cell imaging and electron microscopy suggest that both cell wall synthases locate in the same vesicle. Thus, microtubule-dependent co-delivery of cell wall synthases in the same vesicle is found in asco- and basidiomycetes. [ABSTRACT FROM AUTHOR]

Fusarium fungi are the cause of an array of devastating diseases affecting yield losses and accumulating mycotoxins. Fungicides can be exploited against Fusarium and deoxynivalenol (DON) production. However, Fusarium resistance to common chemicals has become a therapeutic challenge worldwide, which indicates that new control agents carrying different mechanisms of action are desperately needed. Here, we found that a nonantibiotic drug, ethylenediaminetetraacetic acid disodium salt (EDTANa 2 ), exhibited various antifungal activities against Fusarium species and DON biosynthesis. The infection of wheat seeding caused by F. graminearum was suppressed over 90% at 4 mM EDTANa 2 . A similar control effect was observed in field tests. Mycotoxin production assays showed DON production was significantly inhibited, 47% lower than the control, by 0.4 mM EDTANa 2 . In vitro experiments revealed a timely inhibition of H 2 O 2 production as quickly as 4 h after amending cultures with EDTANa 2 and the expression of several TRI genes significantly decreased. Chitin synthases of Fusarium were Mn 2+ -containing enzymes that were strongly inhibited by Mn 2+ deficiency. EDTANa 2 inhibited chitin synthesis and destroyed the cell wall and cytomembrane integrity of Fusarium , mainly via the chelation of Mn 2+ by EDTANa 2 , and thus led to Mn deficiency in Fusarium cells. Taken together, these findings uncover the potential of EDTANa 2 as a fungicide candidate to manage Fusarium head blight (FHB) and DON in agricultural production.

Introduction: Microsporidia have been increasingly reported to infect humans. The most common presentation of microsporidiosis is chronic diarrhea, a significant mortality risk in immune-compromised patients. Albendazole, which inhibits tubulin, and fumagillin, which inhibits methionine aminopeptidase type 2 (MetAP2), are the two main therapeutic agents used for treatment of microsporidiosis. In addition, to their role as emerging pathogens in humans, microsporidia are important pathogens in insects, aquaculture, and veterinary medicine. New therapeutic targets and therapies have become a recent focus of attention for medicine, veterinary, and agricultural use. Areas covered: Herein, we discuss the detection and symptoms of microsporidiosis in humans and the therapeutic targets that have been utilized for the design of new drugs for the treatment of this infection, including triosephosphate isomerase, tubulin, MetAP2, topoisomerase IV, chitin synthases, and polyamines. Expert opinion: Enterocytozoon bieneusi is the most common microsporidia in human infection. Fumagillin has a broader anti-microsporidian activity than albendazole and is active against both Ent. bieneusi and Encephaliozoonidae. Microsporidia lack methionine aminopeptidase type 1 and are, therefore, dependent on MetAP2, while mammalian cells have both enzymes. Thus, MetAP2 is an essential enzyme in microsporidia and new inhibitors of this pathway have significant promise as therapeutic agents.

Chitin synthases are very important enzymes for chitin synthesis in various species, which makes them a specific target of insecticides. In the present study, the function of the chitin synthase A (CHSA) gene isolated from Mythimna separate is investigated. The majority of dsMysCHSA treated larvae (89.50%) exhibit lethal phenotypes, including three phenotypes with severe cuticle deformations. The dsMysCHSA treatment in adult females affects oogenesis, and significantly reduce the ovary size and the oviposition number compared with controls. To determine how MysCHSA affects female fecundity, combined analyses of RNA-sequencing (RNA-Seq) transcriptome and TMT proteome (tandem mass tags) data in M. separata after treatment with MysCHSA-RNAi is performed. The differentially expressed proteins and genes affect fecundity-related proteins, energy metabolism, fatty acid metabolism, amino sugars, and nucleotide sugar metabolism pathways. Taken together, these results suggest that MysCHSA acts on M. separata ecdysis and fecundity, and has the potential as a target gene for pest control., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)