EffectorP 3.0: Prediction of Apoplastic and Cytoplasmic Effectors in Fungi and Oomycetes

Comparative genomics of endophytic fungi Apiospora malaysiana with related ascomycetes indicates adaptation attuned to lifestyle choices with potential sustainable cellulolytic activity

Ascomycetes fungi produce carbohydrate-active enzymes that are prized in the biofuel industry. Comparative genome analysis of endophytic fungus Apiospora malaysiana with seven other closely related high quality genomes of endophytic and pathogenic organisms reveal that effectors and pathogenicity-related genes are predominantly localized within rapidly evolving gene-sparse regions rather than in the conserved region. This suggests bipartite genome architecture where the rapidly evolving region plays a role in host adaptation. Endophytic fungi adapt to plant invasion by enriching enzymes that degrade cellulose, hemicellulose, lignin, and pectin. In contrast, we observed that pathogenic fungi, especially N. oryzae, show a reduced number of secondary metabolites biosynthesis and catabolic genes, reflecting lifestyle adaptation. The presence of exclusive sporulating gene clusters in pathogen species could possibly indicate their pathogenic affiliation. Limited genome plasticity and low heterozygosity in A. malaysiana are in line with its predominant asexual life cycle choices in lab conditions. The secretome of A. malaysiana grown in cellulose-only media had more cellulase activities when compared to cultures grown in YPD media. Genes that were differentially up-regulated in cellulose-only media exhibited strong cellulose-degrading activity and genes involved in evading detection by the hosts surveillance system. Successful cloning and expression of selected CAZymes in bacterial expression systems with desirable physicochemical properties highlight the biotechnological potential of A. malaysiana for sustainable cellulolytic enzyme production. These findings position endophytes as valuable resources for cellulolytic enzyme research and broader bio-industrial applications.

Whole genome sequencing and annotation of Pseudocercospora abelmoschi, a causal agent of black leaf mould of okra

Pseudocercospora abelmoschi causes black mould on the leaves of okra. The disease is prevalent post-rainy season when high moisture and warm temperatures prevail. Severe defoliation is observed during favourable environments, leading to a significant loss in productivity. Based on the importance of the pathogen agriculturally, the P. abelmoschi isolate Cer 86 - 18 (MCC:9491) was selected for genome sequencing. The genome assembly of P. abelmoschi resulted in a genome of 31.90 Mb with an overall GC content of 54.26%. Quantitative genome assessment using BUSCO (Benchmarking Universal Single-Copy Orthologs) identified 1,664 (97.53%) complete BUSCOs, reflecting a high representation of conserved genes with minimal duplication and strong orthologous uniqueness. Gene prediction analysis identified 11,325 protein-coding genes, of which 3,857 were annotated using the KEGG database. As per analyses, 410 genes were predicted to encode carbohydrate-active enzymes, whereas 369 genes were predicted to encode peptidases. Eighteen gene clusters involved in secondary metabolite biosynthesis were also identified. A total of 143 proteins were predicted to be effectors using the in-silico pipeline. This is the first report on the genome organisation of P. abelmoschi. This study was designed to address this gap by enhancing our understanding of the genome organisation of P. abelmoschi and gene annotation, thereby paving the way for functional genomics studies, such as identifying virulence genes to aid in resistance breeding. Also, this genome could be another addition to the available genomic resources of the genus Pseudocercospora and can provide valuable insights into host-pathogen interactions and evolutionary relationships.

An annotated near-complete sequence assembly of the Magnaporthe oryzae 70-15 reference genome

Magnaporthe oryzae is a devastating fungal pathogen that causes substantial yield losses in rice and other cereal crops worldwide. A high-quality genome assembly is critical for addressing challenges posed by this pathogen. However, the current widely used MG8 assembly of the M. oryzae strain 70-15 reference genome contains numerous gaps and unresolved repetitive regions. Here, we report a complete 44.82 Mb high-quality nuclear genome and a 35.95 kb circular mitochondrial genome for strain 70-15, generated using deep-coverage PacBio high-fidelity sequencing (HiFi) and high-resolution chromatin conformation capture (Hi-C) data. Notably, we successfully resolved one or both telomere sequences for all seven chromosomes and achieved telomere-to-telomere (T2T) assemblies for chromosomes 2, 3, 4, 6, and 7. Based on this T2T assembly, we predicted 12,100 protein-coding genes and 493 effectors. This high-quality T2T assembly represents a significant advancement in M. oryzae genomics and provides an enhanced reference for studies in genome biology, comparative genomics, and population genetics of this economically important plant pathogen.

A fungal transcription factor converts a beneficial root endophyte into an anthracnose leaf pathogen

Plant-associated fungi exhibit diverse lifestyles. Fungal endophytes are resident inside plant tissue without showing any disease symptoms for at least a part of their life cycle, and some of them benefit plant growth and health. However, some can cause diseases in specific host environments or genotypes, implying a virulence mechanism, which may be induced by as-yet-unidentified regulatory factors in fungal endophytes. Here, we show that CtBOT6, a transcription factor encoded within a secondary metabolite gene cluster known as the abscisic acid (ABA)-botrydial gene (ABA-BOT) cluster in the root-associated fungus Colletotrichum tofieldiae, triggers virulence-related gene expression and drives the production of diverse metabolites encoded both within and outside the cluster. CtBOT6 overexpression is sufficient to shift a root-beneficial C. tofieldiae to a leaf pathogen, driving its transition along the mutualist-pathogen continuum. Our genetic analysis revealed that the ABA-BOT cluster is indispensable for fungal virulence caused by CtBOT6 activation, implying that compounds derived from the cluster affect these processes. Furthermore, transcriptome analysis of root colonization by C.tofieldiae strains overexpressing CtBOT6 revealed that the pathogenic state induced plant defense and senescence responses characteristic of necrotrophic interactions. Importantly, this state enabled the fungus to proliferate and reproduce in leaves, in addition to heavily colonizing roots, with these processes being partly dependent on the host ABA and ethylene pathways. Our findings indicate that the expression status of CtBOT6 serves as a critical determinant for the endophytic fungus to adapt to the different plant tissues and to manifest diverse infection strategies.

Comprehensive genome analysis of two Cytospora (Cytosporaceae, Diaporthales) species associated with canker disease of spruce: C.piceae and C.piceicola sp. nov

Cytospora canker (CC) is among the most important diseases in conifer trees (Picea spp., mainly). This disease poses a significant risk factor for forest health, potentially leading to economic losses for wood producers. To provide a genomic basis of the CC pathogenesis, the genomes of two Cytospora species associated with the disease were sequenced and further analyzed within a set of Diaporthales species. The first species was identified as C.piceae. The second was described as C.piceicola sp. nov. based on morphological characteristics and multi-gene phylogenetic analysis. The novel species is sister to other Cytospora species isolated from conifers. Here, we report 39.7 and 43.8 Mb highly contiguous genome assemblies of C.piceae EI-19(A) and C.piceicola EI-20, respectively, obtained using Illumina sequencing technology. Despite notably different genome sizes, these species share the main genome characteristics, such as predicted gene number (10,862 and 10,742) and assembly completeness (97.6% and 98.1%). A wide range of genes encoding carbohydrate-active enzymes, secondary metabolite biosynthesis clusters, and secreted effectors were found. Multiple experimentally validated virulence genes were also identified in the studied species. The defined arsenals of enzymes and effectors generally relate to the hemibiotrophic lifestyle with a capability to switch to biotrophy. The obtained evidence also supports that C.piceae EI-19(A) and C.piceicola EI-20 can cause severe canker disease symptoms in Picea spp. specifically. It was additionally observed that the strains of C.piceae may have different pathogenicity and virulence characteristics based on the analyses of predicted secondary metabolite complements, effectomes, and virulence-related genes. Phylogenomic analysis and timetree estimations indicated that divergence of the studied species may have occurred relatively late, 11-10 million years ago. Compared to other members of Diaporthales, C.piceae EI-19(A) and C.piceicola EI-20 implied a moderate rate of gene contraction, but the latter experienced significant gene loss that can additionally support host specificity attributed to these species. But uncovered gene contraction events may point out potential lifestyle differentiation and host shift of the studied species. It was revealed that EI-19(A) and C.piceicola EI-20 carry distinct secretomes and effectomes among Diaporthales species. This feature can indicate a species lifestyle and pathogenicity potential. These findings highlight potential targets for identification and/or detection of pathogenic Cytospora in conifers. The introduced draft genome sequences of C.piceae and C.piceicola can be employed as tools to understand basic genetics and pathogenicity mechanisms of fungal species causing canker disease in woody plants. The identified pathogenicity and virulence-related genes would serve as potential candidates for host-induced gene silencing aimed at making plant hosts more resistant to pathogenic species. Furthermore, the comparative genomics component of the study will facilitate the functional analysis of the genes of unknown function in all fungal pathogens.

Pathogenomics Insights into Phytophthora capsici and Phytophthora tropicalis -Sibling Species Causing Black Pepper Foot Rot: Genomic Architecture, Metabolic Pathways, and Effector Diversity

Foot rot disease in black pepper, caused by Phytophthora species, is a major threat to cultivation. Along with the well-known Phytophthora capsici, a newly identified species, Phytophthora tropicalis, has also been implicated. Comparative genome analysis of P. capsici 05-06 from Kerala (80.51 Mb, 626 scaffolds) and P. tropicalis 98-93 from Karnataka (73.54 Mb, 302 scaffolds) revealed similar GC content (∼50.5%) and gene counts (19,639 and 17,716, respectively). Genomic ANI analysis clustered them with P. capsici LT1534-B, suggesting a species complex. Both species contain transposable elements (19.35% and 21.31%), indicating adaptive evolution. Pathway mapping highlights roles in carbohydrate metabolism, carbohydrate-active enzymes (CAZymes: 575 and 566), energy production, effector biosynthesis, and molecular signaling. The presence of unique protein families and shared orthologous genes underscores their pathogenic potential. These findings enhance understanding of their evolution and pathogenicity, aiding in the development of targeted management strategies for black pepper foot rot.

Fusarium oxysporum NAD+ hydrolase FonNADase1 is essential for pathogenicity and inhibits plant immune responses

Plants use nicotinamide adenine dinucleotide (NAD+) as a key signaling molecule to activate immune responses. However, whether pathogens secrete specific NAD+ hydrolases (NADases) to affect plant NAD+ levels for infection remains unclear. Here, we report the function and possible mechanism of fungal NADases in watermelon Fusarium wilt fungus Fusarium oxysporum f. sp. niveum (Fon) pathogenicity. Fon secretes two NADases, FonNADase1 and FonNADase2, both of which harbor a secretory signal peptide and an NADase-active tuberculosis necrotizing toxin (TNT) domain. FonNADase1 and FonNADase2 are not involved in the growth, development, or stress responses of Fon. Moreover, only FonNADase1 is essential for Fon pathogenicity, and FonNADase1 deletion results in decreased invasive growth and spread within watermelon plants. FonNADase1 and FonNADase2 are functional NADases capable of decreasing plant NAD+ levels and FonNADase1 inhibits INF1- and BAX-induced cell death and chitin-triggered immune responses in Nicotiana benthamiana leaves in an NADase activity-dependent manner. Furthermore, FonNADase1 inhibited INF1- and BAX-induced expression of defense genes, such as NbPR1a, NbPR2, NbLOX, NbERF1, NbHIN1, and NbHSR203J, in N. benthamiana leaves and affected the expression of a set of immunity-associated genes in watermelon plants. These findings suggest that FonNADase1 plays a key role in Fon pathogenicity by affecting fungal invasive growth and spread within plants as well as modulating host immune responses, thus highlighting the critical role of fungal NADases in pathogenicity.

Monkeys at Rigged Typewriters: A Population and Network View of Plant Immune System Incompatibility

Immune system incompatibilities between naturally occurring genomic variants underlie many hybrid defects in plants and present a barrier for crop improvement. In this review, we approach immune system incompatibilities from pan-genomic and network perspectives. Pan-genomes offer insights into how natural variation shapes the evolutionary landscape of immune system incompatibilities, and through it, selection, polymorphisms, and recombination resistance emerge as common features that synergistically drive these incompatibilities. By contextualizing incompatibilities within the immune network, immune receptor promiscuity, complex dysregulation, and single-point failure appear to be recurrent themes of immune system defects. As geneticists break genes to investigate their function, so can we investigate broken immune systems to enrich our understanding of plant immune systems and work toward improving them.

Structure-guided insights into the biology of fungal effectors

Phytopathogenic fungi cause enormous yield losses in many crops, threatening both agricultural production and global food security. To infect plants, they secrete effectors targeting various cellular processes in the host. Putative effector genes are numerous in fungal genomes, and they generally encode proteins with no sequence homology to each other or to other known proteins or domains. Recent studies have elucidated and predicted three-dimensional structures of effectors from a wide diversity of plant pathogenic fungi, revealing a limited number of conserved folds. Effectors with very diverse amino acid sequences can thereby be grouped into families based on structural homology. Some structural families are conserved in many different fungi, and some are expanded in specific fungal taxa. Here, we describe the features of these structural families and discuss recent advances in predicting new structural families. We highlight the contribution of structural analyses to deepen our understanding of the function and evolution of fungal effectors. We also discuss prospects offered by advances in structural modeling for predicting and studying the virulence targets of fungal effectors in plants.

Functional analyses of the salivary protein SaE23 in Sitobion avenae

To counteract host plant defenses, aphids secrete salivary effectors during feeding. Exact functional roles of many salivary effectors in Sitobion avenae (Fabricius), are still elusive. Here, we cloned a salivary glutathione peroxidase (GPx) coding gene (i.e., SaE23) in S. avenae. Our bioinformatics analyses indicated that SaE23 might originate from gene duplication events. Overexpression of SaE23 inhibited Bax-triggered programmed cell death and flg22-elicited reactive oxygen species bursts. The expression patterns showed that SaE23 was predominantly expressed in salivary glands, and its expression increased significantly upon feeding on the resistant wheat cultivar Z4WM. Knockdown of SaE23 significantly reduced aphid survival rates on Z4WM, compared with the susceptible wheat cultivar AK58. Feeding of SaE23 silenced-S. avenae triggered upregulation of TaLOX2 in jasmonic acid pathway, TaICS2 and TaPR-1 in salicylic acid pathway, three MYB transcription factors (TaMYB19, TaMYB29 and TaMYB44) and TaGLS2 for callose synthase genes, which might contribute to decrease performance of SaE23-silenced individuals. Our results showed that SaE23 could be a novel molecular target for management of S. avenae, providing insights into the potential origin of GPx in aphids and molecular mechanisms of GPx modulating aphid-plant interactions.

How genomics can help unravel the evolution of endophytic fungi

Endophytic fungi (EFs) form intimate associations with plants, residing within their tissues without causing apparent harm. Understanding the evolution of endophytic fungal genomes is essential for uncovering the mechanisms that drive their symbiotic relationships with host plants. This review explores the dynamic interactions between EFs and host plants, focusing on the evolutionary processes that shape their genomes. We highlighted key genomic adaptations promoting their endophytic lifestyle, including genes involved in plant cell wall degradation, secondary metabolite production, and stress tolerance. By combining genomic data with ecological and physiological information, this review provides a comprehensive understanding of the coevolutionary dynamics between EFs and host plants. Moreover, it provides insights that help elucidate the complex interdependencies governing their symbiotic interactions.

Exploring the infection strategy of Colletotrichum fructicola in pecan and two effectors Cf-ID1 and Cf-ID2 were characterized using unique molecular identifier-RNA sequencing technology

The anthracnose disease caused by Colletotrichum fructicola has widely occurred in pecan (Carya illinoinensis) in China, seriously affecting its fruit yield and quality. However, the details of the infection strategy of C. fructicola remain to be elucidated. In this study, unique molecular identifier-RNA sequencing (UMI RNA-seq) was used to analyze differentially expressed genes (DEGs) of C. fructicola and candidate effectors were predicted. Two candidate effectors were identified during the early infection stages of C. fructicola. There were 6,822 DEGs at three infection timepoints (6, 24, and 36 h post-inoculation), and these genes were involved in spore germination, nutrient uptake, detoxification, secretion of toxic substances (such as effectors and toxins), inhibition of the host's immune response, and protein post-translational modification, which participated in the pathogenic process of C. fructicola. Moreover, 191 candidate effectors were predicted and their expression trends were divided into five clusters. Two candidate effectors Cf-ID1 and Cf-ID2 were selected for functional validation, and they were demonstrated to trigger cell death and immune response in Nicotiana benthamiana. Cf-ID1 and Cf-ID2 are located in both cytoplasm and nucleus and could suppress the infection of C. fructicola by eliciting defense responses in N. benthamiana. This study provided valuable information for in-depth research on the pathogenesis of C. fructicola.

Genome-wide Evidence of Host Specialization in Wild and Farmland Populations of the Fungal Leaf Spot Pathogen, Cercospora beticola

One of the most recent crop species to be domesticated is sugar beet (Beta vulgaris L. ssp. vulgaris Doell.), which was bred for high sucrose content within the last few centuries in Europe. Crop domestication can also lead to the evolution of novel pathogens, which may spread across large geographical distances with their crop host. In this study, we addressed the recent evolution of the fungal pathogen causing the disease Cercospora leaf spot, Cercospora beticola. This pathogen has become increasingly important in sugar beet and table beet production worldwide. We used genome sequences of 326 C. beticola isolates collected from 4 continents from 4 closely related Beta subspecies (3 domesticated and 1 wild). We applied population genomic analyses to identify signatures of population differentiation and host specialization in C. beticola populations derived from the cultivated and wild hosts. We found evidence that C. beticola populations in agro-ecosystems likely originate from sea beet-infecting isolates. Intriguingly, host jumps from wild to cultivated beet occurred in at least 2 independent events as evidenced by our population data of C. beticola from wild beet collected in the Mediterranean and the UK. We explore the occurrence of genetic variants associated with fungicide resistance and virulence and show that standing genetic variation in C. beticola populations from both wild and domesticated plants may serve as a reservoir of functionally important alleles. Overall, our results highlight the ability of C. beticola to invade the agro-ecosystem and establish new populations, demonstrating the rapid adaptation potential of the species.

Genome-wide screening for virulent candidate secreted effector protein macromolecules in Magnaporthe oryzae

Rice blast, caused by Magnaporthe oryzae (M. oryzae), is a severe threat to rice production globally. The pathogen counters rice immunity by secreting effectors that disrupt host defenses. In this study, we conducted a comprehensive genome-wide screening to identify candidate secreted effector proteins (CSEPs) in M. oryzae. Using a new bioinformatics pipeline, we predicted 577 CSEPs and analyzed their sequence features and functional annotations. We found that these effectors have distinct sequence signatures, such as high cysteine content, and are involved in infection and immune suppression. Phylogenetic analysis revealed M. oryzae's close relationship with other pathogenic fungi and the conservation of certain CSEPs across species. Expression analysis during infection indicated a role of CSEPs in the pathogenic process and the ability to inhibit plant necrosis. Finally, we validated the function of three candidate effector proteins through gene disruption mutant analysis including pathogenesis testing in rice. This study provides a foundation for understanding M. oryzae pathogenicity and may aid in developing resistance strategies against rice blast.

A portable, nanopore-based genotyping platform for near real-time detection of Puccinia graminis f. sp. tritici lineages and fungicide sensitivity

BACKGROUND

Fungal plant disease outbreaks are increasing in both scale and frequency, posing severe threats to agroecosystem stability, native biodiversity and food security. Among these, the notorious wheat stem rust fungus, Puccinia graminis f.sp. tritici (Pgt), has threatened wheat production since the earliest days of agriculture. New Pgt strains continue to emerge and quickly spread over vast distances through the airborne dispersal of asexual urediniospores, triggering extensive disease outbreaks as these exotic Pgt strains often overcome resistance in dominant crop varieties of newly affected regions. This highlights the urgent need for a point-of-care, real-time Pgt genotyping platform to facilitate early detection of emerging Pgt strains.

RESULTS

In this study, we developed a simple amplicon-based re-sequencing platform for rapid genotyping of Pgt isolates. This system is built around a core set of 276 Pgt genes that we found are highly polymorphic between Pgt isolates and showed that the sequence of these genes alone could be used to accurately type Pgt strains to particular lineages. We also developed a simplistic DNA preparation method and an automated bioinformatic pipeline, to enable these Pgt gene markers to be sequenced and analysed rapidly using the MinION nanopore sequencing device. This approach successfully enabled the typing of Pgt strains within approximately 48 h of collecting Pgt-infected wheat samples, even in resource-limited locations in Kenya and Ethiopia. In addition, we incorporated monitoring capabilities for sequence variations in Pgt genes that encode targets of the azole and succinate dehydrogenase inhibitor fungicides, enabling real-time tracking of potential shifts in fungicide sensitivity.

CONCLUSION

The newly developed Pgt Mobile And Real-time, PLant disEase (MARPLE) diagnostics platform we established, now allows precise typing of individual Pgt strains while simultaneously tracking changes in fungicide sensitivity, providing an early warning system for potential indicators of changes in the Pgt population and emerging fungicide resistance. Further integration of this Pgt MARPLE diagnostics platform into national surveillance programmes will support more informed management decisions and timely responses to Pgt disease outbreaks, helping reduce the devastating crop losses currently caused by this 'cereal killer'.

Uncovering the Fungus Responsible for Stem and Root Rot of False Indigo: Pathogen Identification, New Disease Description, and Genome Analyses

Calonectria spp. can cause destructive diseases on forestry crops, legumes like soybean and peanut, and ornamentals. Species of Calonectria affecting ornamental plants are not well characterized or understood, although they have been widely documented as an issue in the ornamental industry. This research focused on the molecular identification, pathogenicity validation, and genome analysis of a Calonectria sp. isolate recovered from ornamental blue false indigo (Baptisia australis) plants showing disease symptoms of crown and root rot in a commercial nursery in Virginia. The fungus on B. australis was identified as C. fujianensis (Nectriaceae, Hypocreales), a member of the C. colhounii species complex, using multilocus sequencing. Pathogenicity tests were fulfilled by inoculating C. fujianensis conidia on B. australis seedlings, confirming a causal relationship between this pathogen and the disease symptoms observed. A 62.7 Mb high-quality hybrid genome assembly generated using Illumina and Nanopore data was obtained, contained in 16 contigs, 4 of which were complete chromosomes. A total of 750 effectors were found in the genome, similar to cutinase and pectinase virulence factors described from other Calonectria species' genomes. Characterization of this novel disease of B. australis advances our understanding of Calonectria as an important but poorly studied group of plant pathogens.

Novel genomic features in entomopathogenic fungus Beauveria bassiana ILB308: accessory genomic regions and putative virulence genes involved in the infection process of soybean pest Piezodorus guildinii

BACKGROUND

Biological control methods involving entomopathogenic fungi like Beauveria bassiana have been shown to be a valuable approach in integrated pest management as an environmentally friendly alternative to control pests and pathogens. Identifying genetic determinants of pathogenicity in B. bassiana is instrumental for enhancing its virulence against insects like the resistant soybean pest Piezodorus guildinii. This study focused on comparative genomics of different B. bassiana strains and gene expression analyses to identify virulence genes in the hypervirulent strain ILB308, especially in response to infection of P. guildinii and growth on hydrocarbon HC15, a known virulence enhancer.

RESULTS

Strain ILB308 showed the highest number of virulence-related features, such as candidate virulence proteins, effectors, small secreted proteins and biosynthetic gene clusters. ILB308 also had a high percentage of unique DNA sequences, including six accessory scaffolds. Gene expression analysis at 4 days post inoculation revealed upregulation of known virulence factors, including Tudor domain proteins, LysM motif-containing proteins, subtilisin-like proteases and novel genes encoding secreted effectors and heat-labile enterotoxins. Growth on HC15 led to the upregulation of genes associated with oxidoreductase activity related to cuticular alkane degradation and fermentation metabolism/antioxidant responses in the hemolymph. The low number of known B. bassiana virulence genes points to novel or unknown mechanisms acting on the interaction between P. guildinii and strain ILB308.

CONCLUSION

The presence of accessory genomic regions and unique virulence genes in ILB308 may contribute to its higher virulence. These genes could be considered as potential targets for enhancing fungal virulence through genetic manipulation. © 2025 Society of Chemical Industry.

A wheat tandem kinase activates an NLR to trigger immunity

The role of nucleotide-binding leucine-rich repeat (NLR) receptors in plant immunity is well studied, but the function of a class of tandem kinases (TKs) that confer disease resistance in wheat and barley remains unclear. In this study, we show that the SR62 locus is a digenic module encoding the Sr62TK TK and an NLR (Sr62NLR), and we identify the corresponding AvrSr62 effector. AvrSr62 binds to the N-terminal kinase 1 of Sr62TK, triggering displacement of kinase 2, which activates Sr62NLR. Modeling and mutation analysis indicated that this is mediated by overlapping binding sites (i) on kinase 1 for binding AvrSr62 and kinase 2 and (ii) on kinase 2 for binding kinase 1 and Sr62NLR. Understanding this two-component resistance complex may help engineering and breeding plants for durable resistance.

Predicting Metal-binding Proteins and Structures Through Integration of Evolutionary-scale and Physics-based Modeling

Metals are essential elements in all living organisms, binding to approximately 50% of proteins. They serve to stabilize proteins, catalyze reactions, regulate activities, and fulfill various physiological and pathological functions. While there have been many advancements in determining the structures of protein-metal complexes, numerous metal-binding proteins still need to be identified through computational methods and validated through experiments. To address this need, we have developed the ESMBind workflow, which combines evolutionary scale modeling (ESM) for metal-binding prediction and physics-based protein-metal modeling. Our approach utilizes the ESM-2 and ESM-IF models to predict metal-binding probability at the residue level. In addition, we have designed a metal-placement method and energy minimization technique to generate detailed 3D structures of protein-metal complexes. Our workflow outperforms other models in terms of residue and 3D-level predictions. To demonstrate its effectiveness, we applied the workflow to 142 uncharacterized fungal pathogen proteins and predicted metal-binding proteins involved in fungal infection and virulence.

Evolutionary genomics reveals variation in structure and genetic content implicated in virulence and lifestyle in the genus Gaeumannomyces

Gaeumannomyces tritici is responsible for take-all disease, one of the most important wheat root threats worldwide. High-quality annotated genome resources are sorely lacking for this pathogen, as well as for the closely related antagonist and potential wheat take-all biocontrol agent, G. hyphopodioides. As such, we know very little about the genetic basis of the interactions in this host-pathogen-antagonist system. Using PacBio HiFi sequencing technology we have generated nine near-complete assemblies, including two different virulence lineages for G. tritici and the first assemblies for G. hyphopodioides and G. avenae (oat take-all). Genomic signatures support the presence of two distinct virulence lineages in G. tritici (types A and B), with A strains potentially employing a mechanism to prevent gene copy-number expansions. The CAZyme repertoire was highly conserved across Gaeumannomyces, while candidate secreted effector proteins and biosynthetic gene clusters showed more variability and may distinguish pathogenic and non-pathogenic lineages. A transition from self-sterility (heterothallism) to self-fertility (homothallism) may also be a key innovation implicated in lifestyle. We did not find evidence for transposable element and effector gene compartmentalisation in the genus, however the presence of Starship giant transposable elements may contribute to genomic plasticity in the genus. Our results depict Gaeumannomyces as an ideal system to explore interactions within the rhizosphere, the nuances of intraspecific virulence, interspecific antagonism, and fungal lifestyle evolution. The foundational genomic resources provided here will enable the development of diagnostics and surveillance of understudied but agriculturally important fungal pathogens.

Uncovering the structural stability of Magnaporthe oryzae effectors: a secretome-wide in silico analysis

Rice blast, caused by the ascomycete fungus Magnaporthe oryzae, is a deadly disease and a major threat to global food security. The pathogen secretes small proteinaceous effectors, virulence factors, inside the host to manipulate and perturb the host immune system, allowing the pathogen to colonize and establish a successful infection. While the molecular functions of several effectors are characterized, very little is known about the structural stability of these effectors. We analyzed a total of 554 small secretory proteins (SSPs) from the M. oryzae secretome to decipher key features of intrinsic disorder (ID) and the structural dynamics of the selected putative effectors through thorough and systematic in silico studies. Our results suggest that out of the total SSPs, 66% were predicted as effector proteins, released either into the apoplast or cytoplasm of the host cell. Of these, 68% were found to be intrinsically disordered effector proteins (IDEPs). Among the six distinct classes of disordered effectors, we observed peculiar relationships between the localization of several effectors in the apoplast or cytoplasm and the degree of disorder. We determined the degree of structural disorder and its impact on protein foldability across all the putative small secretory effector proteins from the blast pathogen, further validated by molecular dynamics simulation studies. This study provides definite clues toward unraveling the mystery behind the importance of structural distortions in effectors and their impact on plant-pathogen interactions. The study of these dynamical segments may help identify new effectors as well.Communicated by Ramaswamy H. Sarma.

Computational studies reveal structural characterization and novel families of Puccinia striiformis f. sp. tritici effectors

Understanding the biological functions of Puccinia striiformis f. sp. tritici (Pst) effectors is fundamental for uncovering the mechanisms of pathogenicity and variability, thereby paving the way for developing durable and effective control strategies for stripe rust. However, due to the lack of an efficient genetic transformation system in Pst, progress in effector function studies has been slow. Here, we modeled the structures of 15,201 effectors from twelve Pst races or isolates, a Puccinia striiformis isolate, and one Puccinia striiformis f. sp. hordei isolate using AlphaFold2. Of these, 8,102 folds were successfully predicted, and we performed sequence- and structure-based annotations of these effectors. These effectors were classified into 410 structure clusters and 1,005 sequence clusters. Sequence lengths varied widely, with a concentration between 101-250 amino acids, and motif analysis revealed that 47% and 5.81% of the predicted effectors contain known effector motifs [Y/F/W]xC and RxLR, respectively highlighting the structural conservation across a substantial portion of the effectors. Subcellular localization predictions indicated a predominant cytoplasmic localization, with notable chloroplast and nuclear presence. Structure-guided analysis significantly enhances effector prediction efficiency as demonstrated by the 75% among 8,102 have structural annotation. The clustering and annotation prediction both based on the sequence and structure homologies allowed us to determine the adopted folding or fold families of the effectors. A common feature observed was the formation of structural homologies from different sequences. In our study, one of the comparative structural analyses revealed a new structure family with a core structure of four helices, including Pst27791, PstGSRE4, and PstSIE1, which target key wheat immune pathway proteins, impacting the host immune functions. Further comparative structural analysis showed similarities between Pst effectors and effectors from other pathogens, such as AvrSr35, AvrSr50, Zt-KP4-1, and MoHrip2, highlighting a possibility of convergent evolutionary strategies, yet to be supported by further data encompassing on some evolutionarily distant species. Currently, our initial analysis is the most one on Pst effectors' sequence, structural and annotation relationships providing a novel foundation to advance our future understanding of Pst pathogenicity and evolution.

The Molecular Dialogue Between Zymoseptoria tritici and Wheat

Zymoseptoria tritici is a highly damaging pathogen that causes high wheat yield losses in temperate climates. Z. tritici emerged during the domestication of wheat in the Fertile Crescent and has been extensively used as a model system for population genetic and genomic studies. New genetic tools and resources have provided a better understanding of the molecular components involved in the wheat-Z. tritici interaction, which is highlighted by the cloning of three wheat resistance genes and four Z. tritici avirulence genes. Despite the considerable progress made in the last few years, the mechanisms that mediate Z. tritici colonization remain largely unknown. In this review, we summarize the latest advances in understanding the molecular components mediating wheat-Z. tritici interactions, and we discuss future research lines to close current knowledge gaps. [Formula: see text] Copyright © 2025 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.

CRISPR-Cas9 genome editing reveals that the Pgs gene of Fusarium circinatum is involved in pathogenicity, growth and sporulation

Fusarium circinatum, the causal agent of pine pitch canker, is one of the most destructive pathogens of Pinus species worldwide. Infections by this pathogen result in serious mortality of seedlings due to root and root collar disease, and growth reduction in trees due to canker formation and dieback. Although much is known about the population biology, genetics, and genomics of F. circinatum, relatively little is known regarding the molecular basis of pathogenicity in F. circinatum. In this study, a protoplast-based transformation using CRISPR-Cas9-mediated genome editing was utilized to functionally characterize a putative pathogenicity gene in three different strains of the fungus. In silico analyses suggested the gene likely encodes a small secreted protein, and all isolates in which it was deleted displayed significantly reduced vegetative growth and asexual spore production compared to the wild-type isolates. In pathogenicity tests, lesions induced by the deletion mutants on detached Pinus patula branches were significantly shorter than those produced by the wild-types. The putative pathogenicity gene was named Pgs reflecting its role in pathogenicity, growth, and sporulation. Future research will seek to explore the molecular mechanisms underlying the mutant phenotypes observed. Overall, this study represents a significant advance in F. circinatum research as the development and application of a Cas9-mediated gene deletion process opens new avenues for functional gene characterization underlying many of the pathogen's biological traits.

Triple Threat: How Global Fungal Rice and Wheat Pathogens Utilize Comparable Pathogenicity Mechanisms to Drive Host Colonization

Plant pathogens pose significant threats to global cereal crop production, particularly for essential crops such as rice and wheat, which are fundamental to global food security and provide nearly 40% of the global caloric intake. As the global population continues to rise, increasing agricultural production to meet food demands becomes even more critical. However, the production of these vital crops is constantly threatened by phytopathological diseases, especially those caused by fungal pathogens such as Magnaporthe oryzae, the causative agent of rice blast disease; Fusarium graminearum, responsible for Fusarium head blight in wheat; and Zymoseptoria tritici, the source of Septoria tritici blotch. All three pathogens are hemibiotrophic, initially colonizing the host through a biotrophic, symptomless lifestyle, followed by causing cell death through the necrotrophic phase. Additionally, they deploy a diverse range of effectors, including proteinaceous and non-proteinaceous molecules, to manipulate fundamental host cellular processes, evade immune responses, and promote disease progression. This review discusses recent advances in understanding the effector biology of these three pathogens, highlighting both the shared functionalities and unique molecular mechanisms they employ to regulate conserved elements of host pathways, such as directly manipulating gene transcription in host nuclei, disrupting reactive oxygen species signaling, interfering with protein stability, and undermining host structural integrity. By detailing these complex interactions, the review explores potential targets for innovative control measures and emphasizes the need for further research to develop effective strategies against these destructive pathogens in the face of evolving environmental and agricultural challenges. [Formula: see text] Copyright © 2025 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Complexity of the lichen symbiosis revealed by metagenome and transcriptome analysis of Xanthoria parietina

Lichens are composite, symbiotic associations of fungi, algae, and bacteria that result in large, anatomically complex organisms adapted to many of the world's most challenging environments. How such intricate, self-replicating lichen architectures develop from simple microbial components remains unknown because of their recalcitrance to experimental manipulation. Here, we report a metagenomic and metatranscriptomic analysis of the lichen Xanthoria parietina at different developmental stages. We identified 168 genomes of symbionts and lichen-associated microbes across the sampled thalli, including representatives of green algae, three different classes of fungi, and 14 bacterial phyla. By analyzing the occurrence of individual species across lichen thalli from diverse environments, we defined both substrate-specific and core microbial components of the lichen. Metatranscriptomic analysis of the principal fungal symbiont from three different developmental stages of a lichen, compared with axenically grown fungus, revealed differential gene expression profiles indicative of lichen-specific transporter functions, specific cell signaling, transcriptional regulation, and secondary metabolic capacity. Putative immunity-related proteins and lichen-specific structurally conserved secreted proteins resembling fungal pathogen effectors were also identified, consistent with a role for immunity modulation in lichen morphogenesis.

IMA GENOME - F20 A draft genome assembly of Agroatheliarolfsii, Ceratobasidiumpapillatum, Pyrenopezizabrassicae, Neopestalotiopsismacadamiae, Sphaerellopsisfilum and genomic resources for Colletotrichumspaethianum and Colletotrichumfructicola

This is a genome announacment there is no abstract

Uncovering the transcriptional landscape of Fomes fomentarius during fungal-based material production through gene co-expression network analysis

BACKGROUND

Fungal-based composites have emerged as renewable, high-performance biomaterials that are produced on lignocellulosic residual streams from forestry and agriculture. Production at an industrial scale promises to revolutionize the world humans inhabit by generating sustainable, low emission, non-toxic and biodegradable construction, packaging, textile, and other materials. The polypore Fomes fomentarius is one of the basidiomycete species used for biomaterial production, yet nothing is known about the transcriptional basis of substrate decomposition, nutrient uptake, or fungal growth during composite formation. Co-expression network analysis based on RNA-Seq profiling has enabled remarkable insights into a range of fungi, and we thus aimed to develop such resources for F. fomentarius.

RESULTS

We analysed gene expression from a wide range of laboratory cultures (n = 9) or biomaterial formation (n = 18) to determine the transcriptional landscape of F. fomentarius during substrate decomposition and to identify genes important for (i) the enzymatic degradation of lignocellulose and other plant-based substrates, (ii) the uptake of their carbon monomers, and (iii) genes guiding mycelium formation through hyphal growth and cell wall biosynthesis. Simple scripts for co-expression network construction were generated and tested, and harnessed to identify a fungal-specific transcription factor named CacA strongly co-expressed with multiple chitin and glucan biosynthetic genes or Rho GTPase encoding genes, suggesting this protein is a high-priority target for engineering adhesion and branching during composite growth. We then updated carbohydrate activated enzymes (CAZymes) encoding gene annotation, used phylogenetics to assign putative uptake systems, and applied network analysis to predict repressing/activating transcription factors for lignocellulose degradation. Finally, we identified entirely new types of co-expressed contiguous clusters not previously described in fungi, including genes predicted to encode CAZymes, hydrophobins, kinases, lipases, F-box domains, chitin synthases, amongst others.

CONCLUSION

The systems biology data generated in this study will enable us to understand the genetic basis of F. fomentarius biomaterial formation in unprecedented detail. We provided proof-of-principle for accurate network-derived predictions of gene function in F. fomentarius and generated the necessary data and scripts for analysis by any end user. Entirely new classes of contiguous co-expressed gene clusters were discovered, and multiple transcription factor encoding genes which are high-priority targets for genetic engineering were identified.

Genomic insights and comparative analysis of Colletotrichum species associated with anthracnose fruit rot and crown rot of strawberry in North Carolina

Colletotrichum is a large genus of fungal phytopathogens responsible for significant economic losses in numerous crops globally. These pathogens exhibit varying host specificities; some have a broad host range, while others are more limited. To explore the genetic composition and underlying factors of fungal virulence and pathogenicity, we sequenced the genomes of seven isolates of Colletotrichum spp.: three from the C. acutatum and four from the C. gloeosporioides. These isolates were sourced from anthracnose fruit rot and crown rot of strawberry in North Carolina. Phylogenetic and phylogenomic analyses classified the isolates within the C. acutatum as C. nymphaeae, while those in the C. gloeosporioides were identified as C. siamense. The genome sizes of the C. nymphaeae isolates ranged from 50.3 Mb to 50.7 Mb, with 14,235 to 14,260 predicted protein-coding gene models. In contrast, the genome sizes of the C. siamense isolates ranged from 55.7 Mb to 58.6 Mb, with predicted protein-coding gene models ranging from 17,420 to 17,729. The GC content across all genomes spanned from 51.9 to 53.7%. The predicted gene models included effectors (339 to 480), secondary metabolic gene clusters (67 to 90), and carbohydrate-active enzymes (800 to 1,060), with C. siamense isolates exhibiting the highest numbers in these categories. The genomic resources from this study will aid in resolving taxonomic challenges associated with Colletotrichum spp., elucidate their evolutionary history, and enhance the understanding of fungal biology and ecology, which is crucial for developing effective disease management strategies.

Dispensable genome and segmental duplications drive the genome plasticity in Fusarium solani

Fusarium solani is a species complex encompassing a large phylogenetic clade with diverse members occupying varied habitats. We recently reported a unique opportunistic F. solani associated with unusual dark galls in sugarbeet. We assembled the chromosome-level genome of the F. solani sugarbeet isolate strain SB1 using Oxford Nanopore and Hi-C sequencing. The average size of F. solani genomes is 54 Mb, whereas SB1 has a larger genome of 59.38 Mb, organized into 15 chromosomes. The genome expansion of strain SB1 is due to the high repeats and segmental duplications within its three potentially accessory chromosomes. These chromosomes are absent in the closest reference genome with chromosome-level assembly, F. vanettenii 77-13-4. Segmental duplications were found in three chromosomes but are most extensive between two specific SB1 chromosomes, suggesting that this isolate may have doubled its accessory genes. Further comparison of the F. solani strain SB1 genome demonstrates inversions and syntenic regions to an accessory chromosome of F. vanettenii 77-13-4. The pan-genome of 12 publicly available F. solani isolates nearly reached gene saturation, with few new genes discovered after the addition of the last genome. Based on orthogroups and average nucleotide identity, F. solani is not grouped by lifestyle or origin. The pan-genome analysis further revealed the enrichment of several enzymes-coding genes within the dispensable (accessory + unique genes) genome, such as hydrolases, transferases, oxidoreductases, lyases, ligases, isomerase, and dehydrogenase. The evidence presented here suggests that genome plasticity, genetic diversity, and adaptive traits in Fusarium solani are driven by the dispensable genome with significant contributions from segmental duplications.

FolSas2 is a regulator of early effector gene expression during Fusarium oxysporum infection

Fusarium oxysporum f. sp. lycopersici (Fol) that causes a globally devastating wilt disease on tomato relies on the secretion of numerous effectors to mount an infection, but how the pathogenic fungus precisely regulates expression of effector genes during plant invasion remains elusive. Here, using molecular and cellular approaches, we show that the histone H4K8 acetyltransferase FolSas2 is a transcriptional regulator of early effector gene expression in Fol. Autoacetylation of FolSas2 on K269 represses K335 ubiquitination, preventing its degradation by the 26S proteasome. During the early infection process, Fol elevates FolSas2 acetylation by differentially changing transcription of itself and the FolSir1 deacetylase, leading to specific accumulation of the enzyme at this stage. FolSas2 subsequently activates the expression of an array of effectors genes, and as a consequence, Fol invades tomato successfully. These findings reveal a regulatory mechanism of effector gene expression via autoacetylation of a histone modifier during plant fungal invasion.

Wheat Leaf Rust Effector Pt48115 Localized in the Chloroplasts and Suppressed Wheat Immunity

Wheat leaf rust caused by Puccinia triticina (Pt) is a prevalent disease worldwide, seriously threatening wheat production. Pt acquires nutrients from host cells via haustoria and secretes effector proteins to modify and regulate the expression of host disease resistance genes, thereby facilitating pathogen growth and reproduction. The study of effector proteins is of great significance for clarifying the pathogenic mechanisms of Pt and effective control of leaf rust. Herein, we report a wheat leaf rust candidate effector protein Pt48115 that is highly expressed in the late stages of infection during wheat-Pt interaction. Pt48115 contains a signal peptide with a secretory function and a transit peptide that can translocate Pt48115 to the host chloroplasts. The amino acid sequence polymorphism analysis of Pt48115 in seven different leaf rust races showed that it was highly conserved. Pt48115 inhibited cell death induced by Bcl-2-associated X protein (BAX) from mice or infestans 1 (INF1) from Phytophthora infestans in Nicotiana benthamiana and by DC3000 in wheat, and its 145-175 amino acids of the C-terminal are critical for its function. Furthermore, Pt48115 inhibited callose deposition and reactive oxygen species accumulation in the wheat cultivar Thatcher, demonstrating that it is an effector that enhances Pt virulence by suppressing wheat defense responses. Our findings lay a foundation for future studies on the pathogenesis of Pt during wheat-fungus interaction.

Endophytic strategies decoded by genome and transcriptome analysis of Fusarium nematophilum strain NQ8GII4

Introduction

Fusarium nematophilum strain NQ8GII4 is an endophytic fungus with significant potential for improving growth and disease resistance of alfalfa. However, the molecular mechanisms underlying the symbiotic relationship between NQ8GII4 and alfalfa roots remain poorly understood.

Methods

In this study, we conducted (1) a comparative genomic analysis of selected saprophytic, pathogenic, and endophytic fungi, including molecular phylogeny analysis, whole-genome alignment, and divergence date estimation positioning, and (2) transcriptomic profiling of alfalfa roots infected with NQ8GII4.

Results

Our findings reveal that NQ8GII4 is genetically closely related to F. solani, suggesting it diverged from Fusarium phytopathogens. During the early stages of symbiosis establishment, genes encoding glycosyltransferases (GTs), fungal cell wall-degrading enzymes (FCWDEs), and steroid-14α-demethylase (CYP51) were significantly downregulated, potentially suppressing hyphal growth of the fungus. Once symbiosis was established, NQ8GII4 secreted effectors that activated plant immunity, which in turn could slow growth of the fungus. Moreover, genes involved in secondary metabolite biosynthesis, such as type I polyketide synthases (T1PKS) and non-ribosomal peptide synthetases (NRPSs), were significantly downregulated. Homologs of autophagy-related genes, including ATG1, ATG2, ATG11, and others, were also downregulated, suggesting that reduced phytotoxin production and autophagy inhibition is a consequence of NQ8GII4's symbiosis.

Discussion

This study investigated the comprehensive molecular and genetic mechanisms governing the interaction between NQ8GII4 and alfalfa roots. Beyond the NQ8GII4-alfalfa system, these findings also provide a valuable molecular framework for understanding the mechanism of interactions between endophytic fungi and their host plants.

Characterizing phenotype variants of Cercosporidium personatum, causal agent of peanut late leaf spot disease, their morphology, genetics and metabolites

Cercosporidium personatum (CP) causes peanut late leaf spot (LLS) disease with 70% yield losses unless controlled by fungicides. CP grows slowly in culture, exhibiting variable phenotypes. To explain those variations, we analyzed the morphology, genomes, transcriptomes and chemical composition of three morphotypes, herein called RED, TAN, and BROWN. We characterized, for the first time in CP, anthraquinone (AQ) precursors of dothistromin (DOT), including averantin, averufin, norsolorinic acid, versicolorin B, versicolorin A, nidurufin and averufanin. BROWN had the highest AQ and melanin (15 mg/g DW) contents. RED had the highest ergosterol (855 µM FW) and chitin (beta-glucans, 4% DW) contents. RED and TAN had higher resistance to xenobiotics (p ≤ 1.0E-3), including chlorothalonil, tebuconazole and caffeine, compared to CP NRRL 64,463. In RED, TAN, and BROWN, rates of single nucleotide polymorphisms (SNP) (1.4-1.7 nt/kb) and amino acid changes (3k-4k) were higher than in NRRL 64,463. Differential gene expression (p ≤ 1.0E-5) was observed in 47 pathogenicity/virulence genes, 41 carbohydrate-active enzymes (CAZymes), and 23 pigment/mycotoxin biosynthesis genes. We describe the MAT1 locus, and a method to evaluate CP-xenobiotic resistance in 5 days. Chemical profiles indicate each CP morphotype could trigger different immune response in plants, probably hindering development of durable LLS resistance.

A conserved fungal Knr4/Smi1 protein is crucial for maintaining cell wall stress tolerance and host plant pathogenesis

Filamentous plant pathogenic fungi pose significant threats to global food security, particularly through diseases like Fusarium Head Blight (FHB) and Septoria Tritici Blotch (STB) which affects cereals. With mounting challenges in fungal control and increasing restrictions on fungicide use due to environmental concerns, there is an urgent need for innovative control strategies. Here, we present a comprehensive analysis of the stage-specific infection process of Fusarium graminearum in wheat spikes by generating a dual weighted gene co-expression network (WGCN). Notably, the network contained a mycotoxin-enriched fungal module (F12) that exhibited a significant correlation with a detoxification gene-enriched wheat module (W12). This correlation in gene expression was validated through quantitative PCR. By examining a fungal module with genes highly expressed during early symptomless infection that was correlated to a wheat module enriched in oxidative stress genes, we identified a gene encoding FgKnr4, a protein containing a Knr4/Smi1 disordered domain. Through comprehensive analysis, we confirmed the pivotal role of FgKnr4 in various biological processes, including oxidative stress tolerance, cell cycle stress tolerance, morphogenesis, growth, and pathogenicity. Further studies confirmed the observed phenotypes are partially due to the involvement of FgKnr4 in regulating the fungal cell wall integrity pathway by modulating the phosphorylation of the MAP-kinase MGV1. Orthologues of the FgKnr4 gene are widespread across the fungal kingdom but are absent in other Eukaryotes, suggesting the protein has potential as a promising intervention target. Encouragingly, the restricted growth and highly reduced virulence phenotypes observed for ΔFgknr4 were replicated upon deletion of the orthologous gene in the wheat fungal pathogen Zymoseptoria tritici. Overall, this study demonstrates the utility of an integrated network-level analytical approach to pinpoint genes of high interest to pathogenesis and disease control.

Genomic features of lichen-associated black fungi

Lichens are mutualistic associations consisting of a primary fungal host, and one to few primary phototrophic symbiont(s), usually a green alga and/or a cyanobacterium. They form complex thallus structures, which provide unique and stable habitats for many other microorganisms. Frequently isolated from lichens are the so-called black fungi, or black yeasts, which are mainly characterized by melanized cell walls and extremophilic lifestyles. It is presently unclear in which ways these fungi interact with other members of the lichen symbiosis. Genomic resources of lichen-associated black fungi are needed to better understand the physiological potential of these fungi and shed light on the complexity of the lichen consortium. Here, we present high-quality genomes of 14 black fungal lineages, isolated from lichens of the rock-dwelling genus Umbilicaria. Nine of the lineages belong to the Eurotiomycetes (Chaetothyriales), four to the Dothideomycetes, and one to the Arthoniomycetes, representing the first genome of a black fungus in this class. The PacBio-based assemblies are highly contiguous (5-42 contigs per genome, mean coverage of 79-502, N50 of 1.0-7.3 mega-base-pair (Mb), Benchmarking Universal Single-Copy Orthologs (BUSCO) completeness generally ≥95.4%). Most contigs are flanked by a telomere sequence, suggesting we achieved near chromosome-level assemblies. Genome sizes range between 26 and 44 Mb. Transcriptome-based annotations yielded ~11,000-18,000 genes per genome. We analyzed genome content with respect to repetitive elements, biosynthetic genes, and effector genes. Each genome contained a polyketide synthase gene related to the dihydroxynaphthalene-melanin pathway. This research provides insights into genome content and metabolic potential of these relatively unknown, but frequently encountered lichen associates.

Genetic Diversity and Population Structure of Plenodomus biglobosus on Flixweed (Descurainia sophia) in Northwestern China

Plenodomus biglobosus (Pb), a causal agent of blackleg of rapeseed, is composed of several subspecies, including 'australensis' (Pba), 'brassicae' (Pbb) and 'canadensis' (Pbc). Besides rapeseed, Pb can infect many wild cruciferous plants (WCPs), such as flixweed (Descurainia sophia) and pennycress (Thlaspi arvense), which may become the infection source for blackleg of rapeseed. However, Pb on WCPs has not been well investigated in China. This study identified the blackleg fungi on two WCPs in Sayram Lake and Zhaosu County in Xinjiang, China: flixweed (15 isolates) and pennycress (1 isolate) as well as on rapeseed (971 isolates). They belonged to Pba (11), Pbb (18), and Pbc (958). Pba occurred on flixweed (10) and pennycress (1) only in Sayram Lake, whereas Pbb and Pbc occurred on flixweed (1 and 4 isolates, respectively) and rapeseed (17 and 954 isolates, respectively) in Zhaosu County. Then, virulence of 16 isolates from flixweed and pennycress was determined on rapeseed. Their genomes were sequenced and used to identify the mating-type idiomorphs and to analyze population genetic structure. Results showed that all of the 16 isolates were virulent to rapeseed. Only MAT1-1 was detected in 11 Pba isolates, implying that Pba may lack sexual reproduction. The 16 isolates from two WCPs were divided into four genetic groups: Group I for Pbc (4 isolates), Group II for Pbb (1 isolate), and Group III (3 isolates) and IV (8 isolates) for Pba. The findings about the single mating type in Pba and its limited geographic distribution provided a case showing the importance of sexual reproduction in epidemics of Pb. To the best of our knowledge, this is the first report of Pba, Pbb, and Pbc on flixweed and Pba on pennycress in China.

The fungal effector AaAlta1 inhibits PATHOGENESIS-RELATED PROTEIN10-2-mediated callose deposition and defense responses in apple

Apple leaf spot, caused by Alternaria alternata f. sp mali (ALT), poses a substantial threat to the global apple (Malus × domestica Borkh.) industry. Fungal effectors promote pathogen infestation and survival by interfering with plant immune responses. In our study, we investigated the secretion of effector proteins by the virulent ALT7 strain. Using mass spectrometry, we identified the effector AaAlta1, which belongs to the Alt a 1 protein family (AA1s). Further analysis confirmed that ALT7 secretes AaAlta1. AaAlta1 knockdown mutants displayed reduced pathogenicity in apple tissue culture seedlings, while overexpression strains exhibited enhanced pathogenicity compared to the wild-type ALT7 strain. Using immunoprecipitation followed by mass spectrometry, we isolated pathogenesis-related protein 10-2 (PR10-2) as an interaction partner of AaAlta1 in apple. Knockdown mutants of AaAlta1 showed increased PR10-2-mediated callose deposition in apple, a critical plant defense response. The enhanced defense responses in apple substantially reduced their susceptibility to infection by these ALT7 mutants. Our findings delineate an infection strategy whereby ALT7 secretes AaAlta1 to suppress PR10-2, thereby circumventing the apple defense system.

Comparative Genomics of Different Lifestyle Fungi in Helotiales (Leotiomycetes) Reveals Temperature and Ecosystem Adaptations

Helotiales, a diverse fungal order within Leotiomycetes (Ascomycota), comprises over 6000 species occupying varied ecological niches, from plant pathogens to saprobes and symbionts. Despite their importance, their genetic adaptations to temperature and environmental conditions are understudied. This study investigates temperature adaptations in infection genes and substrate degradation genes through a comparative genomics analysis of 129 Helotiales species, using the newly sequenced genomes of Gyoerffyella rotula and Anguillospora crassa. Key gene families such as cytochrome P450 enzymes, virulence factors, effector proteins, and carbohydrate-active enzymes (CAZymes) were analyzed to understand their roles in temperature and lifestyle adaptations, uncovering possible alternative lifestyle mechanisms. Our findings reveal that Helotiales fungi possess genes associated with nutrient acquisition, pathogenicity, and symbiotic relationships strongly adapted to cold environments that might be impacted by global warming. On the other hand, some species demonstrate potential for adaptation to warmer climates, suggesting increased activity in response to global warming. This study reveals the adaptive mechanisms enabling Helotiales fungi to thrive in both cold and warm environments. These findings provide valuable insights into their ecological success and evolutionary resilience, which may facilitate their ability to transition between pathogenic, symbiotic, and saprobic phases in response to changing environmental conditions.

Genomic Insights into Fusarium verticillioides Diversity: The Genome of Two Clinical Isolates and Their Demethylase Inhibitor Fungicides Susceptibility

Fusarium verticillioides is an important plant pathogen in maize and other cereals that is seldom detected as the cause of human fusariosis. Here, we provide the analysis of the available diversity of F. verticillioides sequenced worldwide and report the first two genome assemblies and annotations (including mitochondrial DNA) of Fusarium verticillioides from clinical settings. Fusarium verticillioides 05-0160 (IUM05-0160) and Fusarium verticillioides 09-1037 (IUM09-1037) strains were obtained from the bone marrow and blood of two immunocompromised patients, respectively. The phylogenomic analysis confirmed the species identity of our two strains. Comparative genomic analyses among the reannotated F. verticillioides genomes (n = 46) did not lead to the identification of unique genes specific to the clinical samples. Two subgroups in the F. verticillioides clade were also identified and confirmed by a mitochondrial diversity study. Clinical strains (n = 4) were positioned in the multigene phylogenetic tree without any correlation between the host and the tree branches, grouping with plant-derived strains. To investigate the existence of a potential fitness advantage of our two clinical strains, we compared demethylase inhibitor fungicides susceptibility against the reference Fusarium verticillioides 7600, showing, on average, lower susceptibility to agricultural and medical-used antifungals. A significant reduction in susceptibility was observed for itraconazole and tetraconazole, which might be explained by structural changes in CYP51A and CYP51C sequences. By providing the first two annotated genomes of F. verticillioides from clinical settings comprehensive of their mitogenomes, this study can serve as a base for exploring the fitness and adaptation capacities of Fusarium verticillioides infecting different kingdoms.

An effector protein of Fusarium graminearum targets chloroplasts and suppresses cyclic photosynthetic electron flow

Chloroplasts are important photosynthetic organelles that regulate plant immunity, growth, and development. However, the role of fungal secretory proteins in linking the photosystem to the plant immune system remains largely unknown. Our systematic characterization of 17 chloroplast-targeting secreted proteins of Fusarium graminearum indicated that Fg03600 is an important virulence factor. Fg03600 translocation into plant cells and accumulation in chloroplasts depended on its chloroplast transit peptide. Fg03600 interacted with the wheat (Triticum aestivum L.) proton gradient regulation 5-like protein 1 (TaPGRL1), a part of the cyclic photosynthetic electron transport chain, and promoted TaPGRL1 homo-dimerization. Interestingly, TaPGRL1 also interacted with ferredoxin (TaFd), a chloroplast ferredoxin protein that transfers cyclic electrons to TaPGRL1. TaFd competed with Fg03600 for binding to the same region of TaPGRL1. Fg03600 expression in plants decreased cyclic electron flow (CEF) but increased the production of chloroplast-derived reactive oxygen species (ROS). Stably silenced TaPGRL1 impaired resistance to Fusarium head blight (FHB) and disrupted CEF. Overall, Fg03600 acts as a chloroplast-targeting effector to suppress plant CEF and increase photosynthesis-derived ROS for FHB development at the necrotrophic stage by promoting homo-dimeric TaPGRL1 or competing with TaFd for TaPGRL1 binding.

Horizontal transfers between fungal Fusarium species contributed to successive outbreaks of coffee wilt disease

Outbreaks of fungal diseases have devastated plants and animals throughout history. Over the past century, the repeated emergence of coffee wilt disease caused by the fungal pathogen Fusarium xylarioides severely impacted coffee production across sub-Saharan Africa. To improve the disease management of such pathogens, it is crucial to understand their genetic structure and evolutionary potential. We compared the genomes of 13 historic strains spanning 6 decades and multiple disease outbreaks to investigate population structure and host specialisation. We found that F. xylarioides comprised at least 4 distinct lineages: 1 host-specific to Coffea arabica, 1 to C. canephora var. robusta, and 2 historic lineages isolated from various Coffea species. The presence/absence of large genomic regions across populations, the higher genetic similarities of these regions between species than expected based on genome-wide divergence and their locations in different loci in genomes across populations showed that horizontal transfers of effector genes from members of the F. oxysporum species complex contributed to host specificity. Multiple transfers into F. xylarioides populations matched different parts of the F. oxysporum mobile pathogenicity chromosome and were enriched in effector genes and transposons. Effector genes in this region and other carbohydrate-active enzymes important in the breakdown of plant cell walls were shown by transcriptomics to be highly expressed during infection of C. arabica by the fungal arabica strains. Widespread sharing of specific transposons between F. xylarioides and F. oxysporum, and the correspondence of a putative horizontally transferred regions to a Starship (large mobile element involved in horizontal gene transfers in fungi), reinforce the inference of horizontal transfers and suggest that mobile elements were involved. Our results support the hypothesis that horizontal gene transfers contributed to the repeated emergence of coffee wilt disease.

Draft genome sequence data of Pythium cedri Chen 4, the causal pathogen of deodar cedar root rot

Pythium species are distributed globally, with certain members playing significant roles as plant and animal pathogens. Pythium cedri Chen 4 has been identified as a pathogenic isolate responsible for causing root rot on Cedrus deodara. Here, a comprehensive genome-wide sequence of P. cedri strain Chen 4 utilizing the Illumina NovaSeq sequencing platform and a Pacific Biosciences Sequel sequencing platform is presented. The genome of P. cedri strain Chen 4 was assembled into 150 contigs containing a combined size of 41.25 Mb, N50 value of 1,717,859 bp and N90 value of 431,829 bp. Genome annotation revealed 14,077 protein-encoding genes and 364 of the 1016 predicted proteins were putative effectors. The present work enriches the genetic resources of P. cedri for studying its evolution and can contribute to a better understanding of P. cedri-host interaction.

Comprehensive Genomic and Proteomic Analysis Identifies Effectors of Fusarium oxysporum f. sp. melongenae

Fusarium wilt in eggplant caused by F. oxysporum f. sp. melongenae is a major devastating soil-borne disease on a worldwide scale. Effectors play important roles in the interactions in pathogen-plant interactions. Identifying effectors is essential for elucidating the pathogenic mechanisms of phytopathogenic fungi. In this study, bioinformatic prediction approaches, including SignalP v5.0, TMHMM v2.0, WoLF PSORT, PredGPI, and EffectorP, were employed to screen for candidate secreted effector proteins (CSEPs) in F. oxysporum f. sp. melongenae. A total of 1019 proteins exhibiting characteristics typical of classical secretory proteins were identified, 301 of which demonstrated carbohydrate activity, and 194 CSEPs were identified. Furthermore, a total of 563 proteins from F. oxysporum f. sp. melongenae under induced conditions were identified using mass spectrometry-based label-free quantitative proteomics. These findings suggest a potential role of these CSEPs in the interaction between F. oxysporum f. sp. melongenae and eggplant, thereby contributing to a deeper understanding of the pathogenic mechanisms of F. oxysporum f. sp. melongenae and strategies for disease management.

Correlation Between Effector Gene Expression Targeted by lncRNAs in the Oomycete Fish Pathogen, Saprolegnia parasitica

Saprolegniasis caused by Saprolegnia parasitica leads to significant economic losses in the aquaculture industry worldwide. Effector proteins secreted by pathogens are key molecules involved in their pathogenicity and long non-coding lncRNAs (lncRNAs) act as regulators in these processes. However, little is known about the lncRNAs and effector proteins in S. parasitica. Here, we first identified 1027 lncRNAs during the developmental stages and infection process of S. parasitica. Compared with mRNAs, these lncRNAs had shorter sequences and exon lengths and lower expression levels. In addition, their sequence conservation among other oomycete species was also low. The S. parasitica lncRNAs were characterized according to developmental stage and infection time point. We also identified effector proteins using a computational pipeline. In total, 131 S. parasitica effector proteins were identified and classified into 34 families. The 47 genes encoding effector genes were neighbors of 39 lncRNAs, and there was a correlation between the transcription level of lncRNAs and their neighboring genes. Gain- and loss-of-function experiments revealed that lncRNA8375.2 promoted the expression of a neighboring effector gene, SpCAP. Our results provide new data on S. parasitica lncRNAs and effector proteins, and provide insights into the lncRNA-effector module involved in S. parasitica.

A Nanopore-sequenced high-quality genome of the Bipolaris oryzae strain Bo-1

Brown spot disease of rice caused by Bipolaris oryzae results in severe yield losses. A high-quality genome was assembled using Nanopore sequencing data, resulting in a 36-Mb nuclear genome with 19 contigs and a mitogenome. This assembly provides valuable genetic resources for investigations of rice-B. oryzae interactions.

Genomic insights into bamboo witches' broom disease: pathogenicity and phytohormone biosynthesis in Aciculosporium take

Bamboo witches' broom disease (WBD), caused by Aciculosporium take Miyake, devastates bamboo forests. Understanding the genome and pathogenic factors of pathogen is crucial for disease control. We employed single-molecule real-time sequencing, Illumina paired-end sequencing, and chromatin interaction mapping techniques to assemble the genome of A. take CCTCC-M2023413, analyze pathogenicity- and phytohormone-biosynthesis-related genes, and compare it to 12 other WBD pathogens. The genome of A. take is 59.24 Mb in size, with 54.32% repeats, 7 chromosomes, 7,105 protein-coding genes, 84 ribosomal RNAs, and 115 transfer RNAs. Predictive analysis of pathogenicity genes found 237 carbohydrate-active enzymes, 1,069 membrane transport proteins, 1,040 pathogen-host interaction genes, 315 virulence factors, and 70 effectors. Most of pathogenicity genes overlapped with repeat-rich regions. Additionally, 172 genes were linked to auxin biosynthesis, 53 to brassinosteroid biosynthesis, and 2 to cis-zeatin biosynthesis. Comparative genomic analysis identified 77 core orthogroups shared by 13 WBD pathogens, played roles in metabolites, genetic information processing, pathogenesis, cis-zeatin biosynthesis, lifespan, and quorum sensing. The miaA gene, crucial for cis-zeatin biosynthesis, is structurally conserved and sequence-diverse among 13 WBD pathogens, with upregulated expression during bamboo WBD pathogenesis. This highlights that cis-zeatin is significant contributor to host pathogenesis, and miaA is a new potential target for controlling WBD. This study provides important insights on preventing and controlling bamboo WBD.

Roadmap to Success: How Oomycete Plant Pathogens Invade Tissues and Deliver Effectors

Filamentous plant pathogens threaten global food security and ecosystem resilience. In recent decades, significant strides have been made in deciphering the molecular basis of plant-pathogen interactions, especially the interplay between pathogens' molecular weaponry and hosts' defense machinery. Stemming from interdisciplinary investigations into the infection cell biology of filamentous plant pathogens, recent breakthrough discoveries have provided a new impetus to the field. These advances include the biophysical characterization of a novel invasion mechanism (i.e., naifu invasion) and the unraveling of novel effector secretion routes. On the plant side, progress includes the identification of components of cellular networks involved in the uptake of intracellular effectors. This exciting body of research underscores the pivotal role of logistics management by the pathogen throughout the infection cycle, encompassing the precolonization stages up to tissue invasion. More insight into these logistics opens new avenues for developing environmentally friendly crop protection strategies in an era marked by an imperative to reduce the use of agrochemicals.

Transcriptomics reveal a mechanism of niche defense: two beneficial root endophytes deploy an antimicrobial GH18-CBM5 chitinase to protect their hosts

Effector secretion is crucial for root endophytes to establish and protect their ecological niche. We used time-resolved transcriptomics to monitor effector gene expression dynamics in two closely related Sebacinales, Serendipita indica and Serendipita vermifera, during symbiosis with three plant species, competition with the phytopathogenic fungus Bipolaris sorokiniana, and cooperation with root-associated bacteria. We observed increased effector gene expression in response to biotic interactions, particularly with plants, indicating their importance in host colonization. Some effectors responded to both plants and microbes, suggesting dual roles in intermicrobial competition and plant-microbe interactions. A subset of putative antimicrobial effectors, including a GH18-CBM5 chitinase, was induced exclusively by microbes. Functional analyses of this chitinase revealed its antimicrobial and plant-protective properties. We conclude that dynamic effector gene expression underpins the ability of Sebacinales to thrive in diverse ecological niches with a single fungal chitinase contributing substantially to niche defense.

Use of the Puccinia sorghi haustorial transcriptome to identify and characterize AvrRp1-D recognized by the maize Rp1-D resistance protein

The common rust disease of maize is caused by the obligate biotrophic fungus Puccinia sorghi. The maize Rp1-D allele imparts resistance against the P. sorghi IN2 isolate by initiating a defense response that includes a rapid localized programmed cell death process, the hypersensitive response (HR). In this study, to identify AvrRp1-D from P. sorghi IN2, we employed the isolation of haustoria, facilitated by a biotin-streptavidin interaction, as a powerful approach. This method proves particularly advantageous in cases where the genome information for the fungal pathogen is unavailable, enhancing our ability to explore and understand the molecular interactions between maize and P. sorghi. The haustorial transcriptome generated through this technique, in combination with bioinformatic analyses such as SignalP and TMHMM, enabled the identification of 251 candidate effectors. We ultimately identified two closely related genes, AvrRp1-D.1 and AvrRp1-D.2, which triggered an Rp1-D-dependent defense response in Nicotiana benthamiana. AvrRp1-D-induced Rp1-D-dependent HR was further confirmed in maize protoplasts. We demonstrated that AvrRp1-D.1 interacts directly and specifically with the leucine-rich repeat (LRR) domain of Rp1-D through yeast two-hybrid assay. We also provide evidence that, in the absence of Rp1-D, AvrRp1-D.1 plays a role in suppressing the plant immune response. Our research provides valuable insights into the molecular interactions driving resistance against common rust in maize.