In silico analysis of fungal prion-like proteins for elucidating their role in plant-fungi interactions.

Prion-like proteins (PrLPs) have emerged as beneficial molecules with implications in adaptive responses. These proteins possess a conserved prion-like domain (PrLD) which is an intrinsically disordered region capable of adopting different conformations upon perceiving external stimuli. Owing to changes in protein conformation, functional characteristics of proteins harboring PrLDs get altered thereby, providing a unique mode of protein-based regulation. Since PrLPs are ubiquitous in nature and involved in diverse functions, through this study, we aim to explore the role of such domains in yet another important physiological process viz. plant-microbe interactions to get insights into the mechanisms dictating cross-kingdom interactions. We have evaluated the presence and functions of PrLPs in 18 different plant-associated fungi of agricultural importance to unravel their role in plant-microbe interactions. Of the 241,997 proteins scanned, 3,820 (~ 1.6%) were identified as putative PrLPs with pathogenic fungi showing significantly higher PrLP density than their beneficial counterparts. Further, through GO enrichment analysis, we could predict several PrLPs from pathogenic fungi to be involved in virulence and formation of stress granules. Notably, PrLPs involved in (retro)transposition were observed exclusively in pathogenic fungi. We even analyzed publicly available data for the expression alterations of fungal PrLPs upon their interaction with their respective hosts which revealed perturbation in the levels of some PrLP-encoding genes during interactions with plants. Overall, our work sheds light into the probable role of prion-like candidates in plant-fungi interaction, particularly in context of pathogenesis, paving way for more focused studies for validating their role.

Endophytic fungal isolates from apple tissue: Latent pathogens lurking within?

Fungal endophytes inhabit a similar ecological niche to that occupied by many phytopathogens, with several pathogens isolated from healthy tissues in their latent phase. This study aimed to evaluate the pathogenicity, the colonisation ability, and the enzyme activity of 37 endophytic fungal isolates recovered from apparently healthy apple shoot and leaf tissues. The pathogenicity of the isolates was assessed on 'Royal Gala' and 'Braeburn' fruit and detached 'Royal Gala' shoots. For the non-pathogenic isolates, their ability to endophytically colonise detached 'Royal Gala' shoots was evaluated. Enzyme activity assays were undertaken to determine whether the pathogenicity of the endophytes was related to the production of the extracellular enzymes, amylase, cellulase, pectinase, protease, and xylanase. Of the 37 isolates studied, eight isolates, representing the genera Colletotrichum, Diaporthe, Fusarium, and Penicillium, were shown to be pathogenic on both apple shoots and fruit. Two isolates identified as Trichoderma atroviride, were pathogenic only on shoots, and three isolates, representing the genus Diaporthe, were pathogenic only on fruit. Of the remaining 24 isolates, 22 (Biscogniauxia (n = 8), Chaetomium (n = 4), Trichoderma (n = 3), Epicoccum (n = 2), Neosetophoma (n = 2), Xylaria (n = 1), Daldinia (n = 1), and Paraphaeosphaeria (n = 1)) were recovered from the inoculated apple shoots but two failed to colonise the shoot tissues. Of the isolates tested, 20 produced amylase, 15 cellulase, 25 pectinase, 26 protease, and 13 xylanase. There was no correlation between the range and type of enzymes produced by the isolates and their pathogenicity or ability to endophytically colonise the shoot tissue. The study showed that approximately one-third (13/37) of the isolates recovered from the apparently healthy apple shoot tissues were observed as latent pathogens. The isolates that did not cause disease symptoms may have the ability to reduce colonisation of apple tissues by pathogens including Neonectria ditissima associated with European canker of apple.

The abundance and pathogenicity of microbes in automobile air conditioning filters across the typical cities of China and Europe.

Bioaerosols are widely distributed in urban air and can be transmitted across the atmosphere, biosphere, and anthroposphere, resulting in infectious diseases. Automobile air conditioning (AAC) filters can trap airborne microbes. In this study, AAC filters were used to investigate the abundance and pathogenicity of airborne microorganisms in typical Chinese and European cities. Culturable bacteria and fungi concentrations were determined using microbial culturing. High-throughput sequencing was employed to analyze microbial community structures. The levels of culturable bioaerosols in Chinese and European cities exhibited disparities (Analysis of Variance, P < 0.01). The most dominant pathogenic bacteria and fungi were similar in Chinese (Mycobacterium: 18.2-18.9 %; Cladosporium: 23.0-30.2 %) and European cities (Mycobacterium: 15.4-37.7 %; Cladosporium: 18.1-29.3 %). Bartonella, Bordetella, Alternaria, and Aspergillus were also widely identified. BugBase analysis showed that microbiomes in China exhibited higher abundances of mobile genetic elements (MGEs) and biofilm formation capacity than those in Europe, indicating higher health risks. Through co-occurrence network analysis, heavy metals such as zinc were found to correlate with microorganism abundance; most bacteria were inversely associated, while fungi exhibited greater tolerance, indicating that heavy metals affect the growth and reproduction of bioaerosol microorganisms. This study elucidates the influence of social and environmental factors on shaping microbial community structures, offering practical insights for preventing and controlling regional bioaerosol pollution.

The footprint of gut microbiota in gallbladder cancer: a mechanistic review.

Gallbladder cancer (GBC) is the most common malignant tumor of the biliary system with the worst prognosis. Even after radical surgery, the majority of patients with GBC have difficulty achieving a clinical cure. The risk of tumor recurrence remains more than 65%, and the overall 5-year survival rate is less than 5%. The gut microbiota refers to a variety of microorganisms living in the human intestine, including bacteria, viruses and fungi, which profoundly affect the host state of general health, disease and even cancer. Over the past few decades, substantial evidence has supported that gut microbiota plays a critical role in promoting the progression of GBC. In this review, we summarize the functions, molecular mechanisms and recent advances of the intestinal microbiota in GBC. We focus on the driving role of bacteria in pivotal pathways, such as virulence factors, metabolites derived from intestinal bacteria, chronic inflammatory responses and ecological niche remodeling. Additionally, we emphasize the high level of correlation between viruses and fungi, especially EBV and Candida spp., with GBC. In general, this review not only provides a solid theoretical basis for the close relationship between gut microbiota and GBC but also highlights more potential research directions for further research in the future.

The CRZ1 transcription factor in plant fungi: regulation mechanism and impact on pathogenesis.

Calcium (Ca2+) is a universal signaling molecule that is tightly regulated, and a fleeting elevation in cytosolic concentration triggers a signal cascade within the cell, which is crucial for several processes such as growth, tolerance to stress conditions, and virulence in fungi. The link between calcium and calcium-dependent gene regulation in cells relies on the transcription factor Calcineurin-Responsive Zinc finger 1 (CRZ1). The direct regulation of approximately 300 genes in different stress pathways makes it a hot topic in host-pathogen interactions. Notably, CRZ1 can modulate several pathways and orchestrate cellular responses to different types of environmental insults such as osmotic stress, oxidative stress, and membrane disruptors. It is our belief that CRZ1 provides the means for tightly modulating and synchronizing several pathways allowing pathogenic fungi to install into the apoplast and eventually penetrate plant cells (i.e., ROS, antimicrobials, and quick pH variation). This review discusses the structure, function, regulation of CRZ1 in fungal physiology and its role in plant pathogen virulence.

Stalk rot species diversity and molecular phylogeny associated with diseased maize in India.

Stalk rot disease is a major constraint in maize production and till date reported to be caused by two to three species of phytopathogenic fungi but, in our present study, we disclose the first report of stalk rot is caused by complex species of phytopathogens, which belongs to five different genera. Therefore, to substantiate these findings, a total of 105 diseased samples of maize were collected from 21 different locations in six different geographical locations of India from which 48 isolates were used for the research study. Morphological features such as pigmentation, colony color, type of mycelium and pattern of mycelium was examined using macro and microscopic methods. A total of 11 different spp. of pathogens belonging to the five different genera: Fusarium verticillioides (56.25%), F. equiseti (14.5%), F. andiyazi (6.25%), F. solani (2.08%), F. proliferatum (2.08%), F. incarnatum (2.08%), Lasidioplodia theobrame (6.25%), Exserohilum rostrtum (4.16%), Nigrospora spp. (4.16%). and Schizophyllum commune (2.08%) were identified by different housekeeping genes (ITS, TEF-1α, RPB2 and Actin). Fusarium verticillioides, F. equiseti and F. andiyazi were major pathogens involved in stalk rot. This is the first report on F. proliferatum, F. solani, F. incarnatum, Lasidioplodia theobrame, Exserohilum rostrtum, Nigrospora spp. and Schizophyllum commune causing stalk rot of maize and their distribution in the different states of India. Studies on population dynamics of PFSR will enhance the understanding of pathogen behavior, virulence, or its association with different pathogens across India, which will facilitate the development of resistant maize genotypes against the PFSR.

The WHO fungal priority pathogens list: a crucial reappraisal to review the prioritisation.

In October, 2022, WHO published the first fungal priority pathogen list, which categorised 19 fungal entities into three priority groups (critical, high, and medium), for prioritisation of research efforts. The final ranking was determined via multiple criteria decision analysis, considering both research and development needs and perceived public health importance. In this Personal View, we discuss the positioning of the fungal pathogens, namely, Mucorales, Candida spp, Histoplasma spp, Coccidioides and Paracoccidioides spp, Fusarium spp, eumycetoma causative agents, Talaromyces marneffei, and Pneumocystis jirovecii, while expressing concerns about potential disparities between the WHO fungal priority pathogen list ranking and the actual disease burden associated with these pathogens. Finally, we propose a revised prioritisation list that also considers the regional disparities in the burden of fungal diseases.

Advanced genetic techniques in fungal pathogen research.

Although fungi have been important model organisms for solving genetic, molecular, and ecological problems, recently, they are also becoming an important source of infectious disease. Despite their high medical burden, fungal pathogens are understudied, and relative to other pathogenic microbes, less is known about how their gene functions contribute to disease. This is due, in part, to a lack of powerful genetic tools to study these organisms. In turn, this has resulted in inappropriate treatments and diagnostics and poor disease management. There are a variety of reasons genetic studies were challenging in pathogenic fungi, but in recent years, most of them have been overcome or advances have been made to circumvent these barriers. In this minireview, we highlight how recent advances in genetic studies in fungal pathogens have resulted in the discovery of important biology and potential new antifungals and have created the tools to comprehensively study these important pathogens.

Active roles of lytic polysaccharide monooxygenases in human pathogenicity.

Lytic polysaccharide monooxygenases (LPMOs) are redox enzymes widely studied for their involvement in microbial and fungal biomass degradation. The catalytic versatility of these enzymes is demonstrated by the recent discovery of LPMOs in arthropods, viruses, insects and ferns, where they fulfill diverse functions beyond biomass conversion. This mini-review puts a spotlight on a recently recognized aspect of LPMOs: their role in infectious processes in human pathogens. It discusses the occurrence and potential biological mechanisms of LPMOs associated with human pathogens and provides an outlook on future avenues in this emerging and exciting research field.

Impact of climate change and natural disasters on fungal infections.

The effects of climate change and natural disasters on fungal pathogens and the risks for fungal diseases remain incompletely understood. In this literature review, we examined how fungi are adapting to an increase in the Earth's temperature and are becoming more thermotolerant, which is enhancing fungal fitness and virulence. Climate change is creating conditions conducive to the emergence of new fungal pathogens and is priming fungi to adapt to previously inhospitable environments, such as polluted habitats and urban areas, leading to the geographical spread of some fungi to traditionally non-endemic areas. Climate change is also contributing to increases in the frequency and severity of natural disasters, which can trigger outbreaks of fungal diseases and increase the spread of fungal pathogens. The populations mostly affected are the socially vulnerable. More awareness, research, funding, and policies on the part of key stakeholders are needed to mitigate the effects of climate change and disaster-related fungal diseases.

The Roles of Gti1/Pac2 Family Proteins in Fungal Growth, Morphogenesis, Stress Response, and Pathogenicity.

Gti1/Pac2 is a fungal-specific transcription factor family with a stable and conserved N-terminal domain. Generally, there are two members in this family, named Gti1/Wor1/Rpy1/Mit1/Reg1/Ros1/Sge1 and Pac2, which are involved in fungal growth, development, stress response, spore production, pathogenicity, and so on. The Gti1/Pac2 family proteins share some conserved and distinct functions. For example, in Schizosaccharomyces pombe, Gti1 promotes the initiation of gluconate uptake during glucose starvation, while Pac2 controls the onset of sexual development in a pathway independent of the cAMP cascade. In the last two decades, more attention was focused on the Gti1 and its orthologs because of their significant effect on morphological switching and fungal virulence. By contrast, limited work was published on the functions of Pac2, which is required for stress responses and conidiation, but plays a minor role in fungal virulence. In this review, we present an overview of our current understanding of the Gti1/Pac2 proteins that contribute to fungal development and/or pathogenicity and of the regulation mechanisms during infection related development. Understanding the working networks of the conserved Gti1/Pac2 transcription factors in fungal pathogenicity not only advances our knowledge of the highly elaborate infection process but may also lead to the development of novel strategies for the control of plant disease. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Plant size-dependent influence of foliar fungal pathogens promotes diversity through allometric growth.

The effect of pathogens on host diversity has attracted much attention in recent years, yet how the influence of pathogens on individual plants scales up to affect community-level host diversity remains unclear. Here, we assessed the effects of foliar fungal pathogens on plant growth and species richness using allometric growth theory in population-level and community-level foliar fungal pathogen exclusion experiments. We calculated growth scaling exponents of 24 species to reveal the intraspecific size-dependent effects of foliar fungal pathogens on plant growth. We also calculated the intercepts to infer the growth rates of relatively larger conspecific individuals. We found that foliar fungal pathogens inhibited the growth of small conspecific individuals more than large individuals, resulting in a positive allometric growth. After foliar fungal pathogen exclusion, species-specific growth scaling exponents and intercepts decreased, but became positively related to species' relative abundance, providing a growth advantage for individuals of abundant species with a higher growth scaling exponent and intercept compared with rare species, and thus reduced species diversity. By adopting allometric growth theory, we elucidate the size-dependent mechanisms through which pathogens regulate species diversity and provide a powerful framework to incorporate antagonistic size-dependent processes in understanding species coexistence.

Wisconsin bill would restrict pathogen studies.

Efforts to ban "gain-of-function" research on viruses and bacteria worry scientists.

Monitoring the phenology of plant pathogenic fungi: why and how?

Phenology is a key adaptive trait of organisms, shaping biotic interactions in response to the environment. It has emerged as a critical topic with implications for societal and economic concerns due to the effects of climate change on species' phenological patterns. Fungi play essential roles in ecosystems, and plant pathogenic fungi have significant impacts on global food security. However, the phenology of plant pathogenic fungi, which form a huge and diverse clade of organisms, has received limited attention in the literature. This diversity may have limited the use of a common language for comparisons and the integration of phenological data for these taxonomic groups. Here, we delve into the concept of 'phenology' as applied to plant pathogenic fungi and explore the potential drivers of their phenology, including environmental factors and the host plant. We present the PhenoFun scale, a phenological scoring system suitable for use with all fungi and fungus-like plant pathogens. It offers a standardised and common tool for scientists studying the presence, absence, or predominance of a particular phase, the speed of phenological phase succession, and the synchronism shift between pathogenic fungi and their host plants, across a wide range of environments and ecosystems. The application of the concept of 'phenology' to plant pathogenic fungi and the use of a phenological scoring system involves focusing on the interacting processes between the pathogenic fungi, their hosts, and their biological, physical, and chemical environment, occurring during the life cycle of the pathogen. The goal is to deconstruct the processes involved according to a pattern orchestrated by the fungus's phenology. Such an approach will improve our understanding of the ecology and evolution of such organisms, help to understand and anticipate plant disease epidemics and their future evolution, and make it possible to optimise management models, and to encourage the adoption of cropping practices designed from this phenological perspective.