Nick Talbot

• Managing Director at Sainsbury Laboratory

The rice blast fungus Magnaporthe oryzae secretes a battery of effector proteins to facilitate host infection. Among these effectors, Pathogenicity toward Weeping Lovegrass 2 (Pwl2) was originally identified as a host specificity determinant for the infection of weeping lovegrass (Eragrostis curvula) and is also recognized by the barley (Hordeum vu...

Lichens are symbiotic assemblies consisting of multiple organisms, chiefly a fungus and a photosynthetic microorganism or the photobiont. Among diverse photobionts, the most prevalent is the chlorophyte alga Trebouxia. We produced a chromosome-level assembly of Trebouxia sp. 'A48', a photobiont of Xanthoria parietina. The genome was assembled into...

Magnaporthe oryzae is the causal agent of rice blast, one of the most serious diseases affecting rice cultivation around the world. During plant infection, M. oryzae forms a specialised infection structure called an appressorium. The appressorium forms in response to the hydrophobic leaf surface and relies on multiple signalling pathways, including...

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 experimenta...

Plants and animals respond to pathogen attack by mounting innate immune responses that require intracellular nucleotide binding leucine-rich repeat (NLR) proteins. These immune receptors detect pathogen infection by sensing virulence effector proteins. However, the mechanisms by which receptors evolve new recognition specificities remain poorly und...

Filamentous plant pathogens deliver effector proteins into host cells to suppress host defence responses and manipulate metabolic processes to support colonization. Understanding the evolution and molecular function of these effectors provides knowledge about pathogenesis and can suggest novel strategies to reduce damage caused by pathogens. Howeve...

Oomycete protists share phenotypic similarities with fungi, including the ability to cause plant diseases, but branch in a distant region of the tree of life. It has been suggested that multiple horizontal gene transfers (HGTs) from fungi-to-oomycetes contributed to the evolution of plant-pathogenic traits. These HGTs are predicted to include secre...

Septin GTPases are morphogenetic proteins that are widely conserved in eukaryotic organisms fulfilling diverse roles in cell division, differentiation and development. In the filamentous fungal pathogen Magnaporthe oryzae , the causal agent of the devastating blast diseases of rice and wheat, septins have been shown to be essential for plant infect...

The rice blast fungus Magnaporthe oryzae secretes a battery of effector proteins during host infection to suppress plant immunity and promote disease. Among these effectors, the MAX effector-Pwl2 was first identified as a host specificity determinant for infection of weeping lovegrass ( Eragrostis curvula ). However, its biological activity has rem...

Bioengineering of plant immune receptors has emerged as a key strategy for generating novel disease resistance traits to counteract the expanding threat of plant pathogens to global food security. However, current approaches are limited by rapid evolution of plant pathogens in the field and may lack durability when deployed. Here, we show that the...

Rice blast, the most destructive disease of cultivated rice world‐wide, is caused by the filamentous fungus Magnaporthe oryzae. To cause disease in plants, M. oryzae secretes a diverse range of effector proteins to suppress plant defense responses, modulate cellular processes, and support pathogen growth. Some effectors can be secreted by appressor...

Lichen symbiosis is centered around a relationship between a fungus and a photosynthetic microbe, usually a green alga. In addition to their main photosynthetic partner (the photobiont), lichen symbioses can contain additional algae present in low abundance. The biology of these algae and the way they interact with the rest of lichen symbionts rema...

Filamentous plant pathogens deliver effector proteins into host cells to suppress host defence responses and manipulate metabolic processes to support colonization. Understanding the evolution and molecular function of these effectors provides knowledge about pathogenesis and can suggest novel strategies to reduce damage caused by pathogens. Howeve...

Plant nucleotide-binding leucine-rich repeat immune receptors (NLRs) directly or indirectly recognize pathogen-secreted effector molecules to initiate plant defense. Recognition of multiple pathogens by a single NLR is rare and usually occurs via monitoring for changes to host proteins; few characterized NLRs have been shown to recognize multiple e...

Oomycetes are heterotrophic protists that share phenotypic similarities with fungi, including the ability to cause plant diseases, but branch in a separate and distant region of the eukaryotic tree of life. It has been suggested that multiple horizontal gene transfers (HGTs) from fungi-to-oomycetes contributed to the evolution of plant-pathogenic t...

Lichen symbiosis is centered around a relationship between a fungus and a photosynthetic microbe, usually a green alga. In addition to their main photosynthetic partner (the photobiont), lichen symbioses can contain additional algae present in low abundance. The biology of these algae and the way they interact with the rest of lichen symbionts rema...

Fungal cell walls undergo continual remodeling that generates β-1,3-glucan fragments as products of endo-glycosyl hydrolases (GHs), which can be recognized as pathogen-associated molecular patterns (PAMPs) and trigger plant immune responses. How fungal pathogens suppress those responses is often poorly understood. Here, we study mechanisms underlyi...

Many of the world's most devastating crop diseases are caused by fungal pathogens which elaborate specialized infection structures to invade plant tissue. Here we present a quantitative mass spectrometry-based phosphoproteomic analysis of infection-related development by the rice blast fungus Magnaporthe oryzae, which threatens global food security...

Recent findings demonstrate that cytoplasmic effectors from fungal and oomycete pathogens enter plant cells via clathrin-mediated endocytosis (CME). This raises several questions: Does effector secretion pathway facilitate host uptake? How is CME triggered in host cells? How are the effectors released from endosomal compartments to reach diverse su...

The rice blast fungus Magnaporthe oryzae uses a pressurized infection cell called an appressorium to drive a rigid penetration peg through the leaf cuticle. The vast internal pressure of an appressorium is very challenging to investigate, leaving our understanding of the cellular mechanics of plant infection incomplete. Here, using fluorescence lif...

[This corrects the article DOI: 10.1371/journal.pbio.3002052.].

Fungal pathogens undergo specific morphogenetic transitions in order to breach the outer surfaces of plants and invade the underlying host tissue. The ability to change cell shape and switch between non‐polarised and polarised growth habits is therefore critical to the lifestyle of plant pathogens. Infection‐related development involves remodelling...

A cornerstone of classical virulence evolution theories is the assumption that pathogen growth rate is positively correlated with virulence, the amount of damage pathogens inflict on their hosts. Such theories are key for incorporating evolutionary principles into sustainable disease management strategies. Yet, empirical evidence raises doubts over...

Wheat, one of the most important food crops, is threatened by a blast disease pandemic. Here, we show that a clonal lineage of the wheat blast fungus recently spread to Asia and Africa following two independent introductions from South America. Through a combination of genome analyses and laboratory experiments, we show that the decade-old blast pa...

Fungi and oomycetes deliver effectors into living plant cells to suppress defenses and control plant processes needed for infection. Little is known about the mechanism by which these pathogens translocate effector proteins across the plasma membrane into the plant cytoplasm. The blast fungus Magnaporthe oryzae secretes cytoplasmic effectors into a...

To cause rice blast disease, the filamentous fungus Magnaporthe oryzae secretes a battery of effector proteins into host plant tissue to facilitate infection. Effector-encoding genes are expressed only during plant infection and show very low expression during other developmental stages. How effector gene expression is regulated in such a precise m...

The rice blast fungus Magnaporthe oryzae causes a devastating disease that threatens global rice (Oryza sativa) production. Despite intense study, the biology of plant tissue invasion during blast disease remains poorly understood. Here we report a high resolution, transcriptional profiling study of the entire plant-associated development of the bl...

Blast disease in cereal plants is caused by the fungus Magnaporthe oryzae and accounts for a significant loss in food crops. At the outset of infection, expression of a putative polysaccharide monooxygenase (MoPMO9A) is increased. MoPMO9A contains a catalytic domain predicted to act on cellulose and a carbohydrate-binding domain that binds chitin....

Rice blast disease is a major threat to global food security and remains challenging to control in all rice-growing regions of the world. The rice blast fungus Magnaporthe oryzae infects plants with a specialised single-celled infection structure called an appressorium, which develops enormous intracellular turgor to forcibly drive a rigid penetrat...

Plant nucleotide-binding leucine-rich repeat immune receptors (NLRs) directly or indirectly recognize pathogen-secreted effector molecules to initiate plant defense. Recognition of multiple pathogens by a single NLR is rare and usually occurs via monitoring for changes to host proteins; few characterized NLRs have been shown to recognize multiple e...

To cause rice blast disease the filamentous fungus Magnaporthe oryzae secretes a battery of effector proteins into host plant tissue to facilitate infection. Effector-encoding genes are expressed only during plant infection and show very low expression during other developmental stages. How effector gene expression is regulated in such a precise ma...

Many plant pathogenic fungi forcibly enter their hosts to cause disease. The rice blast fungus Magnaporthe oryzae, for example, infects plants using a specialised infection cell called an appressorium, which generates enormous turgor to drive a rigid penetration peg through the rice leaf cuticle. While these vast internal pressures are a critical w...

The blast fungus, Magnaporthe oryzae , is a devastating plant pathogen that threatens global food security. The social and economic importance of blast disease has contributed to this filamentous fungus becoming a model organism for the study of host‐pathogen interactions. Availability of the complete genome sequences of many strains of the pathoge...

The rice blast fungus Magnaporthe oryzae causes a devastating disease which threatens global rice production. In spite of intense study, the biology of plant tissue invasion during blast disease remains poorly understood. Here we report a high resolution, transcriptional profiling study of the entire plant-associated development of the blast fungus...

Many plant pathogenic fungi have the capacity to infect their plant hosts using specialised cells called appressoria. These structures act as a gateway between the fungus and host, allowing entry to internal tissues. Appressoria apply enormous physical force to rupture the plant surface, or use a battery of enzymes to digest the cuticle and plant c...

Wheat, the most important food crop, is threatened by a blast disease pandemic. Here, we show that a clonal lineage of the wheat blast fungus recently spread to Asia and Africa following two independent introductions from South America. Through a combination of genome analyses and laboratory experiments, we show that the decade-old blast pandemic l...

We conducted a survey to assess the occurrence and severity of rice blast and brown spot diseases on popular cultivars grown in the Busia, Kirinyaga, and Kisumu counties of Kenya in 2019. Working with agricultural extension workers within rice production areas, we interviewed farmers (n = 89) regarding their preferred cultivars and their awareness...

Many filamentous eukaryotic plant pathogens, such as fungi and oomycetes, deliver effectors into living plant cells to suppress defenses and control plant processes needed for infection. To date, little is known about the mechanism by which these pathogens translocate effector proteins across the plasma membrane into the plant cytoplasm. The blast...

Rice blast is a devastating disease caused by the fungal pathogen Magnaporthe oryzae that threatens rice production around the world. The fungus produces a specialized infection cell, called the appressorium, that enables penetration through the plant cell wall in response to surface signals from the rice leaf. The underlying biology of plant infec...

There are important biological process involved in rice blast disease that are now well-studied during the early events in plant infection which include: the cell biology of appressorium formation, the biology of invasive growth and effector secretion, the two distinct mechanisms of effector secretion, the nature of the plant-pathogen interface, PA...

To cause disease, many fungal pathogens develop specialised structures to rupture the tough outer layers of their plant or animal hosts. These infection cells, called appressoria, have been extensively studied in many fungal species [1]. However, once inside host tissue, pathogens must also invade new cells and traverse host cell junctions. How the...

Rice is a key food security crop in Africa. The importance of rice has led to increasing country-specific, regional and multinational efforts to develop germplasm and policy initiatives to boost production for a more food secure continent. Currently, this critically important cereal crop is predominantly cultivated by small-scale farmers under sub-...

This introductory chapter describes the life cycle of Magnaporthe oryzae, the causal agent of rice blast disease. During plant infection, M. oryzae forms a specialized infection structure called an appressorium, which generates enormous turgor, applied as a mechanical force to breach the rice cuticle. Appressoria form in response to physical cues f...

In the rice blast fungus Magnaporthe oryzae, the cAMP signalling pathway plays a critical role in regulating leaf surface recognition and the initiation of appressorium development. Direct downstream targets of the cAMP signalling pathway are, however, not well-characterised. The MoSom1 protein functions downstream of the cAMP dependent protein kin...

Magnaporthe oryzae is the causal agent of rice blast disease, the most widespread and serious disease of cultivated rice. Live cell imaging and quantitative 4D image analysis have provided new insight into the mechanisms by which the fungus infects host cells and spreads rapidly in plant tissue. In this video review article, we apply live cell imag...

Chitosan is a partially deacetylated linear polysaccharide composed of β‐1,4‐linked units of d‐glucosamine and N‐acetyl glucosamine. As well as a structural component of fungal cell walls, chitosan is a potent antifungal agent. However, the mode of action of chitosan is poorly understood. Here, we report that chitosan is effective for control of ri...

Glycosylation is a conserved set of post‐translational modifications that exists in all eukaryotic cells. During the last decade, the role of glycosylation in plant pathogenic fungi has received significant attention and considerable progress has been made especially in Ustilago maydis and Magnaporthe oryzae. Here, we review recent advances in our...

Many pathogenic fungi depend on the development of specialized infection structures called appressoria to invade their hosts and cause disease. Impairing the function of fungal infection structures therefore provides a potential means by which diseases could be prevented. In spite of this extraordinary potential, however, relatively few anti-penetr...

Spermine is essential for adhesion to the hydrophobic rice leaf surface by the blast fungus Magnaporthe oryzae during infection.

Many of the world’s most serious crop diseases are caused by hemibiotrophic fungi. These pathogens have evolved the ability to colonize living plant cells, suppressing plant immunity responses, before switching to necrotrophic growth, in which host cells die, providing the energy to fuel sporulation and spread of the fungus. How hemibiotrophic path...

Chitosan is a partially deacetylated linear polysaccharide composed of β-1,4-linked units of D-glucosamine and N-acetyl glucosamine. As well as acting as a structural component of fungal cell walls, chitosan can be applied as a potent antifungal agent. However, the mode-of-action of chitosan in fungal pathogens is poorly understood. Here, we report...

The sorting nexin Atg20/Snx42 plays an important role in autophagy. The wheat head blight pathogen Fusarium graminearum contains an FgAtg20 protein orthologous to S. cerevisiae Atg20/Snx42, but its function remains largely unknown. Here, we report a role for FgAtg20 in regulating morphogenesis and fungal pathogenicity. Cytological observation and W...

Rice blast is a pervasive and devastating disease that threatens rice production across the world. In spite of its importance to global food security, however, the underlying biology of plant infection by the blast fungus Magnaporthe oryzae remains poorly understood. In particular, it is unclear how the fungus elaborates a specialised infection cel...

The rice blast fungus Magnaporthe oryzae causes one of the most devastating crop diseases world-wide and new control strategies for blast disease are urgently required. We have used insertional mutagenesis in M. oryzae to define biological processes that are critical for blast disease. Here, we report the identification of LEU2A by T-DNA mutagenesi...

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

The corn smut fungus uses two different mechanisms to control its cell cycle when it is infecting plants.

The blast fungus Magnaporthe oryzae gains entry to its host plant by means of a specialized pressure-generating infection cell called an appressorium, which physically ruptures the leaf cuticle1,2. Turgor is applied as an enormous invasive force by septin-mediated reorganization of the cytoskeleton and actin-dependent protrusion of a rigid penetrat...

Background: Lichens, encompassing 20,000 known species, are symbioses between specialized fungi (mycobionts), mostly ascomycetes, and unicellular green algae or cyanobacteria (photobionts). Here we describe the first parallel genomic analysis of the mycobiont Cladonia grayi and of its green algal photobiont Asterochloris glomerata. We focus on gen...

Libraries of protein-encoding sequences can be generated by identification of open reading frames (ORFs) from a genome of choice that are then assembled into collections of plasmids termed ORFeome libraries. These represent powerful resources to facilitate functional genomic characterization of genes and their encoded products. Here, we report the...

Outbreaks of emerging plant diseases and insect pests are increasing at an alarming rate threatening the food security needs of a booming world population. The role of plant pathologists in addressing these threats to plant health is critical. Here, we share our personal experience with the appearance in Bangladesh of a destructive new fungal disea...

Outbreaks of fungal diseases have been increased in frequency and are a recurrent risk to global food security. Wheat is the second most important food crop in Bangladesh. In February 2016, wheat blast disease was spotted in Bangladesh for the first time in a country outside of South America. In the first epidemic, 8 districts viz, Pabna, Kushtia,...

Libraries of protein-encoding sequences can be generated by identification of open reading frames (ORFs) from a genome of choice that are then assembled into collections of plasmids termed ORFeome libraries. These represent powerful resources to facilitate functional genomic characterization of genes and their encoded products. Here, we report the...

Significance Horizontal gene transfer (HGT) is the transfer of genetic information between genomes by a route other than from parent to offspring. Of particular interest here are the transfers of transporter-encoding genes, which can allow an organism to utilize a new metabolite, often via the acquisition of a single foreign gene. Here we have iden...

Appressoria are specialised infection structures used by many disease-causing microorganisms to breach the outer surface of a host. Nick Talbot tells us about these small but incredibly powerful structures.

In a review article published in this issue of Molecular Plant Pathology, Ceresini et al. (2019) wrongly treat the wheat blast fungus as a new species, Pyricularia graminis‐tritici (Pygt), following the proposal of Castroagudin et al. (2016). Despite the host specificity implied by the name Pygt, the proposed species concept includes isolates that...

In conclusion, based on the strong evidence, Pygt cannot be considered as a distinct species. Because all strains within Pygt form a subset of the strains in P. oryzae, we formally treat Pygt as a synonym of P. oryzae according to the code of nomenclature of plants, fungi and algae (see below). Resulting from this formal synonymization, P. oryzae,...

The pathogenic life cycle of the rice blast fungus Magnaporthe oryzae involves a series of morphogenetic changes, essential for its ability to cause disease. The smo mutation was identified > 25 years ago, and affects the shape and development of diverse cell types in M. oryzae, including conidia, appressoria, and asci. All attempts to clone the SM...

What do you do when your food is too big to chew, or worse, when you don't have a stomach at all? Richards and Talbot explain how osmotrophs get around the problem by digesting on the outside.

Abstract The rice blast fungus Magnaporthe oryzae is the most serious pathogen of cultivated rice and a significant threat to global food security. To accelerate targeted mutation and specific genome editing in this species, we have developed a rapid plasmid-free CRISPR-Cas9-based genome editing method. We show that stable expression of Cas9 is hig...

The blast fungus Magnaporthe oryzae is comprised of lineages that exhibit varying degrees of specificity on about 50 grass hosts, including rice, wheat and barley. Reliable diagnostic tools are essential given that the pathogen has a propensity to jump to new hosts and spread to new geographic regions. Of particular concern is wheat blast, which ha...

The fungal phytopathogen Magnaporthe oryzae causes blast disease in cereals such as rice and finger millet worldwide. In this study, we assessed genetic diversity of 160 isolates from nine sub-Saharan Africa (SSA) and other principal rice producing countries and conducted a genome-wide association study (GWAS) to identify the genomic regions associ...

The pathogenic life cycle of the rice blast fungus Magnaporthe oryzae involves a series of morphogenetic changes, essential for its ability to cause disease. The smo mutation was identified more than twenty-five years ago and affects the shape and development of diverse cell types in M. oryzae, including conidia, appressoria and asci. All attempts...

Video S1. Rotation of CWA Surrounded by Plasma Membrane Labeled with FORMIN4-GFP, Related to Figure 1

Video S2. Rotation of CWA- (Red) and MAP4-GFP-Labeled Microtubules (Green), Related to Figure S4

Data S1. Exported Output from Genevestigator Showing that FORMIN4 Is the Most Frequently Upregulated Gene from 93 A. thaliana Genes Encoding Core Actin-Binding Proteins among Publicly Available Affymetrix ATH1 Pathogen Exposure Experiments, Related to STAR Methods Experiments are listed in the order of FORMIN4 transcription increase. The third tab...

Autophagy is essential for appressorium-mediated plant infection by Magnaporthe oryzae, the causal agent of rice blast disease and a major threat to global food security. The regulatory mechanism of pathogenicity-associated autophagy, however, remains largely unknown. Here, we report the identification and functional characterization of a plausible...

The rice blast fungus Magnaporthe oryzae is the most serious pathogen of cultivated rice and a significant threat to global food security. To accelerate targeted mutation and specific gene editing in this species, we have developed a rapid plasmid-free CRISPR-Cas9-based gene editing method. It has previously been reported in M. oryzae that transfor...

The blast fungus Magnaporthe oryzae is comprised of lineages that exhibit varying degrees of specificity on about 50 grass hosts, including rice, wheat and barley. Reliable diagnostic tools are essential given that the pathogen has a propensity to jump to new hosts and spread to new geographic regions. Of particular concern is wheat blast, which ha...

Cell wall appositions (CWAs) are produced reactively by the plant immune system to arrest microbial invasion through the local inversion of plant cell growth. This process requires the controlled invagination of the plasma membrane (PM) in coordination with the export of barrier material to the volume between the plant PM and cell wall. Plant actin...

The sections in this article are Introduction Breaching the Host Cuticle Invading Host Tissue Subverting Host Metabolism and Defence Perception of Pathogens Genome‐Level Analysis of Pathogens The Future

The sections in this article are Introduction The Rice Blast Fungus, Magnaporthe Grisea The Onset of Infection: Infection Court Preparation and Appressorium Differentiation Appressorium‐Mediated Plant Infection The Plant Response to Infection: Resistance and Susceptibility Signal Transduction Pathways Mediating Plant Infection Future Explora...

Keeping the channels open When the rice blast fungus enters a rice cell, the plasma membrane stays intact, so the rice cell remains viable. The fungus then moves to adjacent cells via plasmodesmata, the plant's intercellular channels. Sakulkoo et al. used a chemical genetic approach to selectively inhibit a single MAP (mitogen-activated protein) ki...