The Multifaceted Roles of Fungal Cutinases during Infection

A Conserved Endonuclease From Rust Fungi Suppresses Plant Extracellular DNA-Triggered Immunity

Nuclease 1 (NUC1) is a highly conserved nonspecific endonuclease present in vertebrates, fungi, and a few plant species. While the involvement of yeast NUC1p in apoptotic cell death independent of metacaspase or apoptosis-inducing factors is documented, its function in other fungi, particularly pathogenic ones, remains elusive. In this study, we identified and characterised the homologue of yeast NUC1p, termed PstNUC1, in Puccinia striiformis f. sp. tritici (Pst), the causal agent of wheat stripe rust. PstNUC1 was induced during infection and was secreted to the extracellular space of the host. Silencing of PstNUC1 significantly attenuated the virulence of Pst, suggesting its critical role in pathogenicity. Exogenous treatment of PstNUC1 diminished the extracellular DNA (exDNA)-triggered plant immune response, including cell death, oxygen peroxide production, and upregulation of Pathogenesis-related genes. Notably, overexpression of wild-type PstNUC1, but not a signal peptide-deficient mutant (PstNUC1ΔSP), in wheat compromised exDNA-triggered immunity, resulting in enhanced susceptibility to Pst infection. These finding collectively highlight the contribution of PstNUC1 to virulence through degradation of exDNA, thereby dampening the exDNA-induced plant immune response.

Functional characterization of cutinase genes NsCut1-NsCut4 in Neostagonosporella sichuanensis and their effects on fishscale bamboo

Fishscale bamboo rhombic-spot, caused by Neostagonosporella sichuanensis, poses a significant threat to Phyllostachys heteroclada in Sichuan province. Based on genomic analysis, four cutinase genes, NsCut1-NsCut4, were identified, cloned, and functionally validated. Bioinformatics analyses revealed that the proteins encoded by these genes possess secretory functions, lack transmembrane domains, and contain conserved cutinase domains highly homologous to those in other fungi. Recombinant proteins expressed via a prokaryotic system exhibited strong hydrolytic activity against glycerol tributyrate and bamboo white cream at 40°C and pH 8.0, while signal peptide and subcellular localization analyses confirmed their secretory function and localization to the cell wall. Gene knockout experiments were performed to construct deletion strains ΔNsCut and corresponding complemented strains ΔNsCut+. Notably, ΔNsCut1 and ΔNsCut3 resulted in reduced pigmentation, decreased spore production, and increased sensitivity to NaCl, H2O2, and Congo red, along with reduced pathogenicity-indicating that these genes play key roles in metabolic and reproductive processes, oxidative stress responses, and the maintenance of cell wall integrity. In contrast, ΔNsCut2 and ΔNsCut4 did not exhibit significant differences compared to the wild type. This work advances our understanding of the role of cutinases in the pathogenic interaction between N. sichuanensis and P. heteroclada, providing a theoretical basis for further exploration of the pathogen's underlying mechanisms.

Harnessing Fungal Bioagents Rich in Volatile Metabolites for Sustainable Crop Protection: A Critical Review

Pests and diseases have a significant impact on crop health and yields, posing a serious threat to global agriculture. Effective management strategies, such as integrated pest management (IPM), including crop rotation, use of synthetic pesticides, biological control, and resistant/tolerant crop varieties, are essential to mitigate these risks and ensure sustainable agricultural practices. Fungal bioagents play an important role in managing phytopathogens and insect pests by acting as biological agents. They promote healthy plant growth by enhancing the uptake of nutrients and combating systemic resistance in plants. Furthermore, fungal bioagents are environmentally friendly, reducing application of fungicides and insecticides and minimizing their negative impact on the crops and environment. Their use in IPM promotes sustainable agriculture and ensures high-quality crops while maintaining soil health and microbial biodiversity. These fungal bioagents are rich sources of volatile organic compounds (VOCs), which play an important role in biological communication during interaction with insect pests and phytopathogens. In pest management, VOC production by beneficial fungi is accountable for their efficacy against pests and pathogens. Thus, this review discusses the important fungal bioagents producing VOCs, extraction methods of VOC, and the use of VOC-producing fungi in pest and disease management, knowledge gaps, and future research areas.

Feels Like Home: A Biobased and Biodegradable Plastic Offers a Novel Habitat for Diverse Plant Pathogenic Fungi in Temperate Forest Ecosystems

Poly(butylene succinate-co-adipate) (PBSA), a biodegradable plastic, is significantly colonized and degraded by soil microbes under natural field conditions, especially by fungal plant pathogens, raising concerns about potential economic losses. This study hypothesizes that the degradation of biodegradable plastics may increase the presence and abundance of plant pathogens by serving as an additional carbon source, ultimately posing a risk to forest ecosystems. We investigated (i) fungal plant pathogens during the exposure of PBSA in European broadleaved and coniferous forests (two forest types), with a specific focus on potential risk to tree health, and (ii) the response of such fungi to environmental factors, including tree species, soil pH, nutrient availability, moisture content, and the physicochemical properties of leaf litter layer. Next-generation sequencing (NGS) revealed that PBSA harbored a total of 318 fungal plant pathogenic amplicon sequence variants (ASVs) belonging to 108 genera. Among the identified genera (Alternaria, Nectria, Phoma, Lophodermium, and Phacidium), some species have been reported as causative agents of tree diseases. Plenodomus was present in high relative abundances on PBSA, which have not previously been associated with disease in broadleaved and coniferous forests. Furthermore, the highest number of fungal plant pathogens were detected at 200 days of PBSA exposure (112 and 99 fungal plant pathogenic ASV on PBSA degraded under Q. robur and F. sylvatic-dominated forest, respectively), which was double compared mature leaves and needles from the same forest sites. These findings suggest that PBSA attracts fungal plant pathogens in forests as an additional carbon source, potentially leading to increased disease outbreaks and disrupting the stability of forest ecosystems. The fungal plant pathogenic community compositions were mainly shaped by forest type, PBSA exposure time, site locations, leaf litter layer water content, and N:P ratio from leaf litter layer in both forest types. This study provides valuable insights into the potential risks posed by biodegradable plastic degradation in forests after 200 and 400 days of exposure, respectively. Further comprehensive evaluations of their effects on tree health and ecosystems, ideally on a long-term basis, are needed. These evaluations should include integrating microbial investigation, soil health monitoring, and ecosystem interaction assessments. Nevertheless, it should be noted that our interpretation of plant pathogens is solely based on high-throughput sequencing, bioinformatics, and annotation tools.

Comparative secretome analysis unveils species-specific virulence factors in Elsinoe perseae, the causative agent of the scab disease of avocado (Persea americana)

The scab disease, caused by Elsinoe perseae, poses a significant risk to avocado (Persea americana) production in countries with warm and humid climates. Although the genome has been published, the precise virulence factors accountable for the pathogenicity of E. perseae have not yet been determined. The current study employed an in silico approach to identify and functionally characterize the secretory proteins of E. perseae. A total of 654 potential secretory proteins were identified, of which 190 were classified as carbohydrate-active enzymes (CAZymes), 49 as proteases, and 155 as potential effectors. A comparison to six other closely related species identified 40 species-specific putative effectors in E. perseae, indicating their specific involvement in the pathogenicity of E. perseae on avocado. The data presented in this study might be valuable for further research focused on understanding the molecular mechanisms that contribute to the pathogenicity of E. perseae on avocado.

Genome-wide survey of the bipartite structure and pathogenesis-related genes of Neostagonosporella sichuanensis, a causal agent of Fishscale bamboo rhombic-spot disease

Bamboo resources have garnered significant global attention due to their excellent capacity for regeneration and high yield. Rhombic-spot disease, a substantial threat to fishscale bamboo (Phyllostachys heteroclada), is primarily caused by Neostagonosporella sichuanensis. This study first reported the genome assemblies and characteristics of two N. sichuanensis isolates using PacBio and Illumina sequencing platforms. The genomes of N. sichuanensis strain SICAUCC 16-0001 and strain SICAUCC 23-0140, with sizes of 48.0 Mb and 48.4 Mb, respectively, revealed 10,289 and 10,313 protein-coding genes. Additionally, they contained 34.99 and 34.46% repetitive sequences within AT-rich regions, with notable repeat-induced point mutation activity. Comparative genome analysis identified 1,049 contracted and 45 expanded gene families in the genome of N. sichuanensis, including several related to pathogenicity. Several gene families involved in mycotoxin metabolism, secondary metabolism, sterol biosynthesis and transport, and cell wall degradation were contracted. Compared to most analyzed necrotrophic, hemibiotrophic, and phaeosphaeriacous pathogens, the genomes of two N. sichuanensis isolates exhibited fewer secondary metabolite enzymes, carbohydrate-active enzymes, plant cell wall degrading enzymes, secreted proteins, and effectors. Comparative genomics analysis suggested that N. sichuanensis shares more similar characteristics with hemibiotrophic pathogens. Based on single carbon source tests, N. sichuanensis strains demonstrated a higher potential for xylan decomposition than pectin and cellulose. The proportion of cell wall-degrading enzyme effectors occupied a high proportion of the total effectors of the N. sichuanensis genomes. These findings provide valuable insights into uncovering the pathogenesis of N. sichuanensis toward the efficient management of rhombic-spot disease of fishscale bamboo.

Uncovering the Mechanisms: The Role of Biotrophic Fungi in Activating or Suppressing Plant Defense Responses

This paper discusses the mechanisms by which fungi manipulate plant physiology and suppress plant defense responses by producing effectors that can target various host proteins. Effector-triggered immunity and effector-triggered susceptibility are pivotal elements in the complex molecular dialogue underlying plant-pathogen interactions. Pathogen-produced effector molecules possess the ability to mimic pathogen-associated molecular patterns or hinder the binding of pattern recognition receptors. Effectors can directly target nucleotide-binding domain, leucine-rich repeat receptors, or manipulate downstream signaling components to suppress plant defense. Interactions between these effectors and receptor-like kinases in host plants are critical in this process. Biotrophic fungi adeptly exploit the signaling networks of key plant hormones, including salicylic acid, jasmonic acid, abscisic acid, and ethylene, to establish a compatible interaction with their plant hosts. Overall, the paper highlights the importance of understanding the complex interplay between plant defense mechanisms and fungal effectors to develop effective strategies for plant disease management.

Lipids and Lipid-Mediated Signaling in Plant-Pathogen Interactions

Plant lipids are essential cell constituents with many structural, storage, signaling, and defensive functions. During plant-pathogen interactions, lipids play parts in both the preexisting passive defense mechanisms and the pathogen-induced immune responses at the local and systemic levels. They interact with various components of the plant immune network and can modulate plant defense both positively and negatively. Under biotic stress, lipid signaling is mostly associated with oxygenated natural products derived from unsaturated fatty acids, known as oxylipins; among these, jasmonic acid has been of great interest as a specific mediator of plant defense against necrotrophic pathogens. Although numerous studies have documented the contribution of oxylipins and other lipid-derived species in plant immunity, their specific roles in plant-pathogen interactions and their involvement in the signaling network require further elucidation. This review presents the most relevant and recent studies on lipids and lipid-derived signaling molecules involved in plant-pathogen interactions, with the aim of providing a deeper insight into the mechanisms underpinning lipid-mediated regulation of the plant immune system.

ANCUT1, a novel thermoalkaline cutinase from Aspergillus nidulans and its application on hydroxycinnamic acids lipophilization

One of the four cutinases encoded in the Aspergillus nidulans genome, ANCUT1, is described here. Culture conditions were evaluated, and it was found that this enzyme is produced only when cutin is present in the culture medium, unlike the previously described ANCUT2, with which it shares 62% amino acid identity. The differences between them include the fact that ANCUT1 is a smaller enzyme, with experimental molecular weight and pI values of 22 kDa and 6, respectively. It shows maximum activity at pH 9 and 60 °C under assayed conditions and retains more than 60% of activity after incubation for 1 h at 60 °C in a wide range of pH values (6-10) after incubations of 1 or 3 h. It has a higher activity towards medium-chain esters and can modify long-chain length hydroxylated fatty acids constituting cutin. Its substrate specificity properties allow the lipophilization of alkyl coumarates, valuable antioxidants and its thermoalkaline behavior, which competes favorably with other fungal cutinases, suggests it may be useful in many more applications.

Functional characterization and structural insights of three cutinases from the ascomycete Fusarium verticillioides

Cutinases are serine esterases that belong to the α/β hydrolases superfamily. The natural substrates for these enzymes are cutin and suberin, components of the plant cuticle, the first barrier in the defense system against pathogen invasion. It is well-reported that plant pathogens produce cutinases to facilitate infection. Fusarium verticillioides, one important corn pathogens, is an ascomycete upon which its cutinases are poorly explored. Consequently, the objective of this study was to perform the biochemical characterization of three precursor cutinases (FvCut1, FvCut2, and FvCut3) from F. verticillioides and to obtain structural insights about them. The cutinases were produced in Escherichia coli and purified. FvCut1, FvCut2, and FvCut3 presented optimal temperatures of 20, 40, and 35 °C, and optimal pH of 9, 7, and 8, respectively. Some chemicals stimulated the enzymatic activity. The kinetic parameters revealed that FvCut1 has higher catalytic efficiency (Kcat/Km) in the p-nitrophenyl-butyrate (p-NPB) substrate. Nevertheless, the enzymes were not able to hydrolyze polyethylene terephthalate (PET). Furthermore, the three-dimensional models of these enzymes showed structural differences among them, mainly FvCut1, which presented a narrower opening cleft to access the catalytic site. Therefore, our study contributes to exploring the diversity of fungal cutinases and their potential biotechnological applications.

FsCGBP, a Cutinase G-Box Binding Protein, Regulates the Growth, Development, and Virulence of Fusarium sacchari, the Pathogen of Sugarcane Pokkah Boeng Disease

Fusarium sacchari is a causal agent of sugarcane Pokkah boeng, an important fungal disease that causes a considerable reduction in yield and sugar content in susceptible varieties of sugarcane worldwide. Despite its importance, the fungal factors that regulate the virulence of this pathogen remain largely unknown. In our previous study, mapping of an insertional mutant defect in virulence resulted in the identification of a cutinase G-box binding protein gene, designated FsCGBP, that encodes a C2H2-type transcription factor (TF). FsCGBP was shown to localize in the nuclei, and the transcript level of FsCGBP was significantly upregulated during the infection process or in response to abiotic stresses. Deletion or silencing of FsCGBP resulted in a reduction in mycelial growth, conidial production, and virulence and a delay in conidial germination in the F. sacchari. Cutinase genes FsCUT2, FsCUT3, and FsCUT4 and the mitogen-activated protein kinase (MAPK) genes FsHOG1, FsMGV1, and FsGPMK1, which were significantly downregulated in ΔFsCGBP. Except for FsHOG1, all of these genes were found to be transcriptionally activated by FsCGBP using the yeast one-hybrid system in vitro. The deletion of individual cutinase genes did not result in any of the phenotypes exhibited in the ΔFsCGBP mutant, except for cutinase activity. However, disruption of the MAPK pathway upon deletion of FsMGV1 or FsGPMK1 resulted in phenotypes similar to those of the ΔFsCGBP mutant. The above results suggest that FsCGBP functions by regulating the MAPK pathway and cutinase genes, providing new insights into the mechanism of virulence regulation in F. sacchari.

Fungal Cell Wall-Associated Effectors: Sensing, Integration, Suppression, and Protection

The cell wall (CW) of plant-interacting fungi, as the direct interface with host plants, plays a crucial role in fungal development. A number of secreted proteins are directly associated with the fungal CW, either through covalent or non-covalent interactions, and serve a range of important functions. In the context of plant-fungal interactions many are important for fungal development in the host environment and may therefore be considered fungal CW-associated effectors (CWAEs). Key CWAE functions include integrating chemical/physical signals to direct hyphal growth, interfering with plant immunity, and providing protection against plant defenses. In recent years, a diverse range of mechanisms have been reported that underpin their roles, with some CWAEs harboring conserved motifs or functional domains, while others are reported to have novel features. As such, the current understanding regarding fungal CWAEs is systematically presented here from the perspective of their biological functions in plant-fungal interactions. An overview of the fungal CW architecture and the mechanisms by which proteins are secreted, modified, and incorporated into the CW is first presented to provide context for their biological roles. Some CWAE functions are reported across a broad range of pathosystems or symbiotic/mutualistic associations. Prominent are the chitin interacting-effectors that facilitate fungal CW modification, protection, or suppression of host immune responses. However, several alternative functions are now reported and are presented and discussed. CWAEs can play diverse roles, some possibly unique to fungal lineages and others conserved across a broad range of plant-interacting fungi. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.

Exploring the infiltrative and degradative ability of Fusarium oxysporum on polyethylene terephthalate (PET) using correlative microscopy and deep learning

Managing the worldwide steady increase in the production of plastic while mitigating the Earth's global pollution is one of the greatest challenges nowadays. Fungi are often involved in biodegradation processes thanks to their ability to penetrate into substrates and release powerful catabolic exoenzymes. However, studying the interaction between fungi and plastic substrates is challenging due to the deep hyphal penetration, which hinders visualisation and evaluation of fungal activity. In this study, a multiscale and multimodal correlative microscopy workflow was employed to investigate the infiltrative and degradative ability of Fusarium oxysporum fungal strain on polyethylene terephthalate (PET) fragments. The use of non-destructive high-resolution 3D X-ray microscopy (XRM) coupled with a state-of-art Deep Learning (DL) reconstruction algorithm allowed optimal visualisation of the distribution of the fungus on the PET fragment. The fungus preferentially developed on the edges and corners of the fragment, where it was able to penetrate into the material through fractures. Additional analyses with scanning electron microscopy (SEM), Raman and energy dispersive X-ray spectroscopy (EDX) allowed the identification of the different phases detected by XRM. The correlative microscopy approach unlocked a more comprehensive understanding of the fungus-plastic interaction, including elemental information and polymeric composition.

Microorganisms that produce enzymes active on biodegradable polyesters are ubiquitous

Biodegradability standards measure ultimate biodegradation of polymers by exposing the material under test to a natural microbial inoculum. Available tests developed by the International Organization for Standardization (ISO) use inoculums sampled from different environments e.g. soil, marine sediments, seawater. Understanding whether each inoculum is to be considered as microbially unique or not can be relevant for the interpretation of tests results. In this review, we address this question by consideration of the following: (i) the chemical nature of biodegradable plastics (virtually all biodegradable plastics are polyesters) (ii) the diffusion of ester bonds in nature both in simple molecules and in polymers (ubiquitous); (iii) the diffusion of decomposers capable of producing enzymes, called esterases, which accelerate the hydrolysis of esters, including polyesters (ubiquitous); (iv) the evidence showing that synthetic polyesters can be depolymerized by esterases (large and growing); (v) the evidence showing that these esterases are ubiquitous (growing and confirmed by bioinformatics studies). By combining the relevant available facts it can be concluded that if a certain polyester shows ultimate biodegradation when exposed to a natural inoculum, it can be considered biodegradable and need not be retested using other inoculums. Obviously, if the polymer does not show ultimate biodegradation it must be considered recalcitrant, until proven otherwise.

In Vitro Insight on Antifungal-Specific Potentiality of Ni(II) Complex against Colletotrichum siamense and Fusarium equisetum Phytopathogens

In an initiation to investigate a prospective bioactive compound, a mononuclear Ni(II) complex with N, N, and O donor Schiff base ligand was synthesized and characterized in the present study through FTIR, ESI-mass, and X-ray crystallographic diffraction studies. A slightly distorted octahedral geometry has been obtained for the Ni(II) complex from X-ray crystallographic diffraction studies. In vitro comprehensive biological studies show the antifungal specific efficiency of the complex against Colletotrichum siamense (AP1) and Fusarium equisetum (F.E.) pathogens, which are responsible for anthracnose and wilt disease, respectively, but no inhibitory effect on both Gram-positive and Gram-negative bacteria. The minimum inhibitory concentration (MIC) for these pathogens was observed to be 0.25 and 0.5 mM, respectively. The experiment also reveals that significant damage of mycelia and enlarged, misshaped damaged spores are noticed in comparison to hexaconazole, used as a positive control under a light microscope post 48 h treatment of AP1 and F.E. with the MIC of the complex. The binding interaction studies of the complex with DNA and BSA performed through a variety of spectroscopic techniques demonstrate a strong binding behavior of the complex for both the binding systems. The observed negative ΔH° and ΔS° values for DNA reveal the existence of hydrogen-bonding/van der Waals interactions for DNA which was also exemplified from the molecular docking and self-assembly studies of the complex. The positive ΔH° and ΔS° values for BSA demonstrate the hydrophobic interactions of the complex with BSA. However, cytotoxicity studies against the MDA-MB-231 breast cancer cell line did not demonstrate any significant potentiality of the complex as an anticancer agent. All the bio-experimental studies provide clear evidence that the synthesized Ni(II) complex exhibits potential antifungal activity and could be used as a therapeutic fungicide agent in comparison to hexaconazole in agricultural practices.

Unraveling the role of effector proteins in Bipolaris oryzae infecting North East Indian rice cultivars through time-course transcriptomics analysis

Bipolaris oryzae, causing brown spot disease in rice, is one of the neglected diseases reducing rice productivity. Limited knowledge is available on the genetics of host-pathogen interaction. Here, we used time-course transcriptome sequencing to elucidate the differential transcriptional responses of the pathogen genes in two contradictory infection-responsive rice hosts. Evaluation of transcriptome data showed similar regulation of fungal genes within susceptible (1733) and resistant (1846) hosts at an early stage however, in the later stage, the number was significantly higher in susceptible (2877) compared to resistant (1955) hosts. GO enrichment terms for upregulated genes showed a similar pattern in both the hosts at an early stage, but in the later stage terms related to degradation of carbohydrates, carbohydrate transport, and pathogenesis are enriched extensively within the susceptible host. Likewise, similar expression responses were observed with the secretory and effector proteins. Plant pathogenic homologs genes such as those involved in appressorium and conidia formation, host cell wall degradative enzymes, etc. were reported to be highly upregulated within the susceptible host. This study predicts the successful establishment of B. oryzae BO1 in both the host surfaces at an early stage, while disease progression only occurs in the susceptible host in later stage.

Eight Up-Coming Biotech Tools to Combat Climate Crisis

Biotechnology has a high potential to substantially contribute to a low-carbon society. Several green processes are already well established, utilizing the unique capacity of living cells or their instruments. Beyond that, the authors believe that there are new biotechnological procedures in the pipeline which have the momentum to add to this ongoing change in our economy. Eight promising biotechnology tools were selected by the authors as potentially impactful game changers: (i) the Wood-Ljungdahl pathway, (ii) carbonic anhydrase, (iii) cutinase, (iv) methanogens, (v) electro-microbiology, (vi) hydrogenase, (vii) cellulosome and, (viii) nitrogenase. Some of them are fairly new and are explored predominantly in science labs. Others have been around for decades, however, with new scientific groundwork that may rigorously expand their roles. In the current paper, the authors summarize the latest state of research on these eight selected tools and the status of their practical implementation. We bring forward our arguments on why we consider these processes real game changers.

Appressoria-Small but Incredibly Powerful Structures in Plant-Pathogen Interactions

Plant-pathogenic fungi are responsible for many of the most severe crop diseases in the world and remain very challenging to control. Improving current protection strategies or designating new measures based on an overall understanding of molecular host-pathogen interaction mechanisms could be helpful for disease management. The attachment and penetration of the plant surface are the most important events among diverse plant-fungi interactions. Fungi evolved as small but incredibly powerful infection structure appressoria to facilitate attachment and penetration. Appressoria are indispensable for many diseases, such as rusts, powdery mildews, and blast diseases, as well as devastating oomycete diseases. Investigation into the formation of plant-pathogen appressoria contributes to improving the understanding of the molecular mechanisms of plant-pathogen interactions. Fungal host attachment is a vital step of fungal pathogenesis. Here, we review recent advances in the molecular mechanisms regulating the formation of appressoria. Additionally, some biocontrol agents were revealed to act on appressorium. The regulation of fungal adhesion during the infective process by acting on appressoria formation is expected to prevent the occurrence of crop disease caused by some pathogenic fungi.

Five Previously Unrecorded Fungal Species Isolated from Marine Plastic Wastes in South Korea

Plastic wastes have a negative impact on marine environments; however, they can be used as carbon sources and habitats by certain microbes. Microbes in the marine plastisphere can migrate worldwide through the ocean and cause serious environmental problems when they encounter suitable environments. Therefore, efforts to investigate the microbes inhabiting the marine plastisphere are increasing. In the present study, fungal strains were isolated from plastic wastes buried in Korean sea sands and mudflats and identified using molecular and morphological analyses. Five species were identified that were previously unrecorded from South Korea: Cladosporium funiculosum, Neosetophoma poaceicola, Neosetophoma rosigena, Parasarocladium gamsii, and Trichoderma fomiticola. Their molecular phylogenies and morphological characteristics are described in this study.

The control of Fusarium growth and decontamination of produced mycotoxins by lactic acid bacteria

Global crop and food contamination with mycotoxins are one of the primary worldwide concerns, while there are several restrictions regarding approaching conventional physical and chemical mycotoxins decontamination methods due to nutrition loss, sensory attribute reduction in foods, chemical residual, inconvenient operation, high cost of equipment, and high energy consumption of some methods. In this regard, the overarching challenges of mycotoxin contamination in food and food crops require the development of biological decontamination strategies. Using certain lactic acid bacteria (LAB) as generally recognized safe (GRAS) compounds is one of the most effective alternatives due to their potential to release antifungal metabolites against various fungal factors species. This review highlights the potential applications of LAB as biodetoxificant agents and summarizes their decontamination activities against Fusarium growth and Fusarium mycotoxins released into food/feed. Firstly, the occurrence of Fusarium and the instrumental and bioanalytical methods for the analysis of mycotoxins were in-depth discussed. Upgraded knowledge on the biosynthesis pathway of mycotoxins produced by Fusarium offers new insightful ideas clarifying the function of these secondary metabolites. Moreover, the characterization of LAB metabolites and their impact on the decontamination of the mycotoxin from Fusarium, besides the main mechanisms of mycotoxin decontamination, are covered. While the thematic growth inhibition of Fusarium and decontamination of their mycotoxin by LAB is very complex, approaching certain lactic acid bacteria (LAB) is worth deeper investigations.

Fungal Enzymes Involved in Plastics Biodegradation

Plastic pollution is a growing environmental problem, in part due to the extremely stable and durable nature of this polymer. As recycling does not provide a complete solution, research has been focusing on alternative ways of degrading plastic. Fungi provide a wide array of enzymes specialized in the degradation of recalcitrant substances and are very promising candidates in the field of plastic degradation. This review examines the present literature for different fungal enzymes involved in plastic degradation, describing their characteristics, efficacy and biotechnological applications. Fungal laccases and peroxidases, generally used by fungi to degrade lignin, show good results in degrading polyethylene (PE) and polyvinyl chloride (PVC), while esterases such as cutinases and lipases were successfully used to degrade polyethylene terephthalate (PET) and polyurethane (PUR). Good results were also obtained on PUR by fungal proteases and ureases. All these enzymes were isolated from many different fungi, from both Basidiomycetes and Ascomycetes, and have shown remarkable efficiency in plastic biodegradation under laboratory conditions. Therefore, future research should focus on the interactions between the genes, proteins, metabolites and environmental conditions involved in the processes. Further steps such as the improvement in catalytic efficiency and genetic engineering could lead these enzymes to become biotechnological applications in the field of plastic degradation.

Sclerotinia sclerotiorum SsCut1 Modulates Virulence and Cutinase Activity

The plant cuticle is one of the protective layers of the external surface of plant tissues. Plants use the cuticle layer to reduce water loss and resist pathogen infection. Fungi release cell wall-degrading enzymes to destroy the epidermis of plants to achieve the purpose of infection. Sclerotinia sclerotiorum secretes a large amount of cutinase to disrupt the cuticle layer of plants during the infection process. In order to further understand the role of cutinase in the pathogenic process of S. sclerotiorum, the S. sclerotiorum cutinsae 1 (SsCut1) gene was cloned and analyzed. The protein SsCut1 contains the conserved cutinase domain and a fungal cellulose-binding domain. RT-qPCR results showed that the expression of SsCut1 was significantly upregulated during infection. Split-Marker recombination was utilized for the deletion of the SsCut1 gene, ΔSsCut1 mutants showed reduced cutinase activity and virulence, but the deletion of the SsCut1 gene had no effect on the growth rate, colony morphology, oxalic acid production, infection cushion formation and sclerotial development. Complementation with the wild-type SsCut1 allele restored the cutinase activity and virulence to the wild-type level. Interestingly, expression of SsCut1 in plants can trigger defense responses, but it also enhanced plant susceptibility to SsCut1 gene knock-out mutants. Taken together, our finding demonstrated that the SsCut1 gene promotes the virulence of S. sclerotiorum by enhancing its cutinase activity.