http://hdl.handle.net/10366/4029 2026-05-01T16:41:30Z http://hdl.handle.net/10366/169986 [EN]Trichoderma gamsii T6085 has been investigated for many years as a beneficial isolate for use in the biocontrol of Fusarium head blight (FHB) of wheat caused primarily by Fusarium graminearum. Previous work focused on application of T6085 to wheat spikes at anthesis, whereas application to soil before or at sowing has received limited attention. In the present study, the competitive ability of T6085 on plant residues against F. graminearum was investigated. Results showed a significant reduction of wheat straw colonization by the pathogen and of the development of perithecia, not only when T6085 was applied alone but also in the presence of a F. oxysporum isolate (7121), well known as a natural competitor on wheat plant residues. T6085 was able to endophytically colonize wheat roots, resulting in internal colonization of the radical cortex area, without reaching the vascular system, as confirmed by confocal microscopy. This intimate interaction with the plant resulted in a significant increase of the expression of the plant defense-related genes PAL1 and PR1. Taken together, competitive ability, endophytic behavior, and host resistance induction represent three important traits that can be of great use in the application of T6085 against FHB not only on spikes at anthesis but potentially also in soil before or at sowing 2021-01-01T00:00:00Z http://hdl.handle.net/10366/169937 [EN]Colletotrichum is a fungal genus (Ascomycota, Sordariomycetes, Glomerellaceae) that includes many economically important plant pathogens that cause devastating diseases of a wide range of plants. In this work, using a combination of long- and short-read sequencing technologies, we sequenced the genome of Colletotrichum lupini RB221, isolated from white lupin (Lupinus albus) in France during a survey in 2014. The genome was assembled into 11 nuclear chromosomes and a mitochondrial genome with a total assembly size of 63.41 Mb and 36.55 kb, respectively. In total, 18,324 protein-encoding genes have been predicted, of which only 39 are specific to C. lupini. This resource will provide insight into pathogenicity factors and will help provide a better understanding of the evolution and genome structure of this important plant pathogen 2021-12-01T00:00:00Z http://hdl.handle.net/10366/169930 [EN]KP4 killer toxins are secreted proteins that inhibit cell growth and induce cell death in target organisms. In Fusarium graminearum, KP4-like (KP4L) proteins contribute to fungal virulence in wheat seedling rot and are expressed during Fusarium head blight development. However, fungal KP4L proteins are also hypothesized to support fungal antagonism by permeabilizing cell walls of competing fungi to enable penetration of toxic compounds. Here, we report the differential expression patterns of F. graminearum KP4L genes (Fgkp4l-1, -2, -3 and -4) in a competitive interaction, using Trichoderma gamsii as the antagonist. The results from dual cultures indicate that Fgkp4l-3 and Fgkp4l-4 could participate in the recognition at the distance of the antagonist, while all Fgkp4l genes were highly activated in the pathogen during the physical interaction of both fungi. Only Fgkp4l-4 was up-regulated during the interaction with T. gamsii in wheat spikes. This suggests the KP4L proteins could participate in supporting F. graminearum interspecific interactions, even in living plant tissues. The distribution of KP4L orthologous within the genus Fusarium revealed they are more represented in species with broad host-plant range than in host-specific species. Phylogeny inferred provides evidence that KP4L genes evolved through gene duplications, gene loss and sequence diversification in the genus Fusarium 2022-09-16T00:00:00Z http://hdl.handle.net/10366/169920 [EN]Species of fungal genus Trichoderma are characterized by a versatile lifestyle, high adaptability to the changing environmental conditions and the ability to establish sophisticated interactions with other organisms. Due to their ability to antagonize plant pathogens and to elicit the plant defence responses against biotic/abiotic stresses, Trichoderma spp. are commonly used as commercially biopesticides and biofertilizers. The Trichoderma success in the rhizosphere is supported by a wide arsenal of specialised metabolites (SMs) providing morphological and physiological autoregulation, self-protection and facilitating fungal communication. This review aims to explore the roles of SMs in the biology of fungi, with special emphasis on the genus Trichoderma and on how divergence in the SMs genetic structure determine Trichoderma lifestyles. Trichoderma genomes are endowed with a high number of SMs biosynthetic genes, and understanding the genetic basis of their biosynthesis is crucial for determining the role of these metabolites in Trichoderma ecophysiology and for expanding their application in crop protection. Recent advances on the characterization of the Trichoderma SMs genetic inventory driven by computational biology are discussed 2022-01-01T00:00:00Z http://hdl.handle.net/10366/169919 [EN]Trichoderma is a fungal genus comprising species used as biocontrol agents in crop plant protection and with high value for industry. The beneficial efects of these species are supported by the secondary metabolites they produce. Terpenoid compounds are key players in the interaction of Trichoderma spp. with the environment and with their fungal and plant hosts; however, most of the terpene synthase (TS) genes involved in their biosynthesis have yet not been characterized. Here, we combined comparative genomics of TSs of 21 strains belonging to 17 Trichoderma spp., and gene expression studies on TSs using T. gamsii T6085 as a model. An overview of the diversity within the TS-gene family and the regulation of TS genes is provided. We identified 15 groups of TSs, and the presence of clade-specific enzymes revealed a variety of terpenoid chemotypes evolved to cover diferent ecological demands. We propose that functional diferentiation of gene family members is the driver for the high number of TS genes found in the genomes of Trichoderma. Expression studies provide a picture in which diferent TS genes are regulated in many ways, which is a strong indication of diferent biological functions. 2020-10-01T00:00:00Z http://hdl.handle.net/10366/169918 [EN]Fungal pathogens are the main factors responsible for the most severe diseases affecting plants, leading to significant reduction in yield and crop quality and causing enormous economic losses worldwide. It is estimated that around 30% of the emerging diseases are caused by fungi thus requiring new strategies to improve their management. Biological control approach, frequently referred to the use of non-pathogenic microbial antagonists or products derived from their metabolism, represents a valid and promising alternative under a more ecological perspective to reduce the activities and to control populations of target pathogens. However, although the use of antagonists belonging to species different from that of the pathogen has been successfully reported, the use of competitors belonging to the same species of the pathogen is not widespread. A biocontrol strategy based on competition for space and nutrients and/or the induction of plant defenses against virulent pathogens performed by attenuated or avirulent pathogens could, therefore, be considered a valid alternative. 2019-02-15T00:00:00Z http://hdl.handle.net/10366/169917 [EN]Fusarium graminearum está entre los principales agentes causales del tizón de la espiga por Fusarium (FHB) o escabiosis en trigo y otros cereales, enfermedad presente en todo el mundo y producida por un complejo de especies de Fusarium. Además de causar pérdidas económicas importantes en rendimiento y calidad de los cultivos, F. graminearum representa una amenaza grave para la salud animal y humana. En este trabajo presentamos la primera secuencia genómica preliminar (borrador) del genoma completo de la cepa micotoxigénica Fusarium graminearum ITEM 124, proporcionando además información útil para estudios de genómica comparativa. 2017-11-09T00:00:00Z http://hdl.handle.net/10366/169884 [EN]The gene Bcin04g03490 has been shown to control development and pathogenicity in the plant necrotroph Botrytis cinerea. We have identified the orthologous gene in two formae speciales of the Fusarium oxysporum species complex; it maps to chromosome 7 in the core genome of the lycopersici forma specialis. It encodes a protein with two distinct domains, a GAL4-like Zn(II)2Cys6 binuclear cluster DNA-binding domain and an acetyltransferase domain, as previously shown in B. cinerea. Null mutants were generated in both formae speciales (phaseoli and lycopersici), and the phenotypes exhibited during in culture growth and plant colonization were analyzed. The results obtained demonstrate that this virulence factor is required for complete colonization of the plant host stem vascular tissue and full virulence in F. oxysporum but not for the initial stages of root colonization. In addition, null mutants showed a severe alteration in the formation of aerial mycelia and a drastic reduction of sporulation. These observations are consistent with a master role of FoG4MAT in the gene regulation of different processes crucial for normal development and full disease induction in the plant host. 2025-07-01T00:00:00Z http://hdl.handle.net/10366/169874 [EN]Natural populations provide valuable information and resources for addressing the genetic characterization of biological systems. Botrytis cinerea is a necrotrophic fungus that exhibits complex responses to light. Physiological analysis of B. cinerea populations from vineyards in Castilla y León (Spain) allowed for the identification of isolate Bc116. This field isolate shows a reduced pathogenicity that is conditioned by the light regime. Light also delays germination and accentuates the negative effect it exerts on the vegetative growth of B. cinerea. Bc116 also displays a marked hyperconidiation phenotype and a characteristic sclerotia production pattern. Genetic analysis demonstrates that the alternative phenotypes regarding pathogenicity, conidiation, and pattern of sclerotia production co-segregate in the progeny of crosses between isolate Bc116 and a wild-type field isolate, Bc448, showing that they are under the control of a single locus. By applying a strategy based on bulked segregant analysis, the mutation in Bc116 has been mapped to a 200 kb region on Chr14 and the analysis of this region identifies a 2 kb deletion affecting the bcltf1 gene, encoding the B. cinerea Light Responsive Transcription Factor 1 described in the reference isolate B05.10. Transformation of Bc116 with the B05.10 bcltf1 allele restored the wild-type phenotypes, providing functional evidence that the natural mutant Bc116 is altered in gene bcltf1. This study offers additional information, derived from the analysis of the genetic background of a natural mutant, on the physiological processes regulated by BcLTF1 and supports the key role of this TF in the pathogenicity and photobiology of B. cinerea. 2025-04-08T00:00:00Z http://hdl.handle.net/10366/169868 [EN]Botrytis cinerea, a necrotrophic fungus responsible for grey rot disease, causes substantial economic losses. However, recent studies have discovered distinct non-sporogenic and non-infective isolates of this species, such as the B459 field strain. Examination of these isolates is particularly intriguing in the context of the development of methodological applications that could be useful in the biocontrol of this phytopathogenic species. This investigation revealed that B459 exhibited a reduced growth rate yet displayed enhanced resilience to stressors like oxidative stress agents, SDS, ethanol, and PhITC. Notably, its ability to generate reactive oxygen species (ROS) and acidic compounds, crucial in plant–pathogen interactions, was impacted. Bio-targeted toxin identification assays and the metabolomic study of extracts obtained from fermentations at seven and fourteen days revealed that this strain does not biosynthesize botrydial and derivatives neither botcinin family toxins. Furthermore, its inability to infect tomato fruits, grape, and gerbera petals coincides with its lack of toxin production under culture conditions typically adapted for reference strain B05.10. 2024-01-01T00:00:00Z http://hdl.handle.net/10366/169865 [EN]Protoplast transformation for the introduction of recombinant DNA into Aspergillus nidulans is technically demanding and dependant on the availability and batch variability of commercial enzyme preparations. Given the success of Agrobacterium tumefaciens-mediated transformation (ATMT) in diverse pathogenic fungi, we have adapted this method to facilitate transformation of A. nidulans. Using suitably engineered binary vectors, gene-targeted ATMT of A. nidulans non-homologous end-joining (NHEJ) mutant conidia has been carried out for the first time by complementation of a nutritional requirement (uridine/uracil auxotrophy). Site-specific integration in the ΔnkuA host genome occurred at high efficiency. Unlike other transformation techniques, however, cross-feeding of certain nutritional requirements from the bacterium to the fungus was found to occur, thus limiting the choice of auxotrophies available for ATMT. In complementation tests and also for comparative purposes, integration of recombinant cassettes at a specific locus could provide a means to reduce the influence of position effects (chromatin structure) on transgene expression. In this regard, targeted disruption of the wA locus permitted visual identification of transformants carrying site-specific integration events by conidial colour (white), even when auxotrophy selection was compromised due to cross-feeding. The protocol described offers an attractive alternative to the protoplast procedure for obtaining locus-targeted A. nidulans transformants. 2021-11-12T00:00:00Z http://hdl.handle.net/10366/169492 [EN]In fission yeast, the septation initiation network (SIN) ensures temporal coordination between actomyosin ring (CAR) constriction with membrane ingression and septum synthesis. However, questions remain about CAR regulation under stress conditions. We show that Rgf1p (Rho1p GEF), participates in a delay of cytokinesis under cell wall stress (blankophor, BP). BP did not interfere with CAR assembly or the rate of CAR constriction, but did delay the onset of constriction in the wild type cells but not in the rgf1D cells. This delay was also abolished in the absence of Pmk1p, the MAPK of the cell integrity pathway (CIP), leading to premature abscission and a multi-septated phenotype. Moreover, cytokinesis delay correlates with maintained SIN signaling and depends on the SIN to be achieved. Thus, we propose that the CIP participates in a checkpoint, capable of triggering a CAR constriction delay through the SIN pathway to ensure that cytokinesis terminates successfully. 2020-01-01T00:00:00Z http://hdl.handle.net/10366/169181 [EN]Antimicrobial resistance (AMR) poses a global threat to human, animal and environmental health. Among the multidisciplinary tasks aimed at collectively tackling the AMR crisis, surveillance, research and education stand as major priorities. Based on a crowdsourcing research strategy, the MicroMundo project, a partner of the Tiny Earth initiative in Spain and Portugal, has been developed and consolidated with success in the academic environment. The objectives are focused on promoting research and, especially, on bringing knowledge of One Health and microbiology concepts, as well as AMR awareness to the community. Following a service-learning approach, MicroMundo integrates university and secondary/high school students in a citizen science-based research project to collectively isolate microorganisms with the potential to produce new antibiotics from soil environments. Over the last 7 years, 32 MicroMundo hubs operating across 31 different Portuguese and Spanish universities have recruited thousands of teenagers in this quest. Here we review the outcome of this unprecedented effort from a scientific and an educational perspective. 2025-01-01T00:00:00Z http://hdl.handle.net/10366/169007 [EN]Microtubules (MTs) are hollow cylinders made of tubulin, a GTPase responsible for essential functions during cell growth and division, and thus, key target for anti-tumor drugs. In MTs, GTP hydrolysis triggers structural changes in the lattice, which are responsible for interaction with regulatory factors. The stabilizing GTP-cap is a hallmark of MTs and the mechanism of the chemical-structural link between the GTP hydrolysis site and the MT lattice is a matter of debate. We have analyzed the structure of tubulin and MTs assembled in the presence of fluoride salts that mimic the GTP-bound and GDP•Pi transition states. Our results challenge current models because tubulin does not change axial length upon GTP hydrolysis. Moreover, analysis of the structure of MTs assembled in the presence of several nucleotide analogues and of taxol allows us to propose that previously described lattice expansion could be a post-hydrolysis stage involved in Pi release. 2020-03-10T00:00:00Z http://hdl.handle.net/10366/169005 [EN]We report the in vivo regulation of Inosine-5´-monophosphate dehydrogenase 1 (IMPDH1) in the retina. IMPDH1 catalyzes the rate-limiting step in the de novo synthesis of guanine nucleotides, impacting the cellular pools of GMP, GDP and GTP. Guanine nucleotide homeostasis is central to photoreceptor cells, where cGMP is the signal transducing molecule in the light response. Mutations in IMPDH1 lead to inherited blindness. We unveil a light-dependent phosphorylation of retinal IMPDH1 at Thr159/Ser160 in the Bateman domain that desensitizes the enzyme to allosteric inhibition by GDP/GTP. When exposed to bright light, living mice increase the rate of GTP and ATP synthesis in their retinas; concomitant with IMPDH1 aggregate formation at the outer segment layer. Inhibiting IMPDH activity in living mice delays rod mass recovery. We unveil a novel mechanism of regulation of IMPDH1 in vivo, important for understanding GTP homeostasis in the retina and the pathogenesis of adRP10 IMPDH1 mutations. 2020-04-07T00:00:00Z http://hdl.handle.net/10366/169003 [EN]Thioredoxin reductases control the redox state of thioredoxins (Trxs)—ubiquitous proteins that regulate a spectrum of enzymes by dithiol–disulfide exchange reactions. In most organisms, Trx is reduced by NADPH via a thioredoxin reductase flavoenzyme (NTR), but in oxygenic photosynthetic organisms, this function can also be performed by an iron-sulfur ferre- doxin (Fdx)-dependent thioredoxin reductase (FTR) that links light to metabolic regulation. We have recently found that some cyanobacteria, such as the thylakoid-less Gloeobacter and the ocean-dwelling green oxyphotobacterium Prochlorococcus, lack NTR and FTR but contain a thioredoxin reductase flavoenzyme (formerly tentatively called deeply- rooted thioredoxin reductase or DTR), whose electron donor remained undefined. Here, we demonstrate that Fdx func- tions in this capacity and report the crystallographic structure of the transient complex between the plant-type Fdx1 and the thioredoxin reductase flavoenzyme from Gloeobacter violaceus. Thereby, our data demonstrate that this cyanobacterial enzyme belongs to the Fdx flavin-thioredoxin reductase (FFTR) family, originally described in the anaerobic bacterium Clostridium pasteurianum. Accordingly, the enzyme hitherto termed DTR is renamed FFTR. Our experiments further show that the redox-sensitive peptide CP12 is modulated in vitro by the FFTR/Trx system, demonstrating that FFTR functionally substitutes for FTR in light-linked enzyme regulation in Gloeobacter. Altogether, we demonstrate the FFTR is spread within the cyanobacteria phylum and propose that, by substituting for FTR, it connects the reduction of target proteins to photo- synthesis. Besides, the results indicate that FFTR acquisition constitutes a mechanism of evolutionary adaptation in marine phytoplankton such as Prochlorococcus that live in low-iron environments. 2021-02-18T00:00:00Z