Frontiers in fungal biology最新文献

[This corrects the article DOI: 10.3389/ffunb.2024.1451455.].

The complex and dynamic interactions between fungi and plants constitute a critical arena in ecological science. In this comprehensive review paper, we explore the multifaceted relationships at the fungi-plant interface, encompassing both mutualistic and antagonistic interactions, and the environmental factors influencing these associations. Mutualistic associations, notably mycorrhizal relationships, play a pivotal role in enhancing plant health and ecological balance. On the contrary, fungal diseases pose a significant threat to plant health, agriculture, and natural ecosystems, such as rusts, smuts, powdery mildews, downy mildews, and wilts, which can cause extensive damage and lead to substantial economic losses. Environmental constraints encompassing abiotic and biotic factors are elucidated to understand their role in shaping the fungi-plant interface. Temperature, moisture, and soil conditions, along with the presence of other microbes, herbivores, and competing plants, significantly influence the outcome of these interactions. The interplay between mutualism and antagonism is emphasised as a key determinant of ecosystem health and stability. The implications of these interactions extend to overall ecosystem productivity, agriculture, and conservation efforts. The potential applications of this knowledge in bioremediation, biotechnology, and biocontrol strategies emphasise the importance of adapting to climate change. However, challenges and future directions in this field include the impacts of climate change, emerging fungal pathogens, genomic insights, and the role of the fungi-plant interface in restoration ecology. Hence, this review paper provides a comprehensive overview of fungi-plant interactions, their environmental influences, and their applications in agriculture, conservation, and ecological restoration.

Southwest Spain's Río Tinto is a stressful acidic microbial habitat with a noticeably high concentration of toxic heavy metals. Nevertheless, it has an unexpected degree of eukaryotic diversity in its basin, with a high diversity of fungal saprotrophs. Although some studies on the eukaryotic diversity in Rio Tinto have been published, none of them used molecular methodologies to describe the fungal diversity and taxonomic affiliations that emerge along the river in different seasons. The aim of the present study was to isolate and describe the seasonal diversity of the fungal community in the Río Tinto basin and its correlation with the physicochemical parameters existing along the river's course. The taxonomic affiliation of 359 fungal isolates, based on the complete internal transcribed spacer DNA sequences, revealed a high degree of diversity, identifying species belonging primarily to the phylum Ascomycota, but representatives of the Basidiomycota and Mucoromycota phyla were also present. In total, 40 representative isolates along the river were evaluated for their tolerance to toxic heavy metals. Some of the isolates were able to grow in the presence of 1000 mM of Cu²⁺, 750 mM of As⁵⁺ and Cd²⁺, and 100 mM of Co²⁺, Ni²⁺, and Pb²⁺.

Colletotrichum lindemuthianum is the etiological agent of anthracnose disease in common bean (Phaseolus vulgaris L.), noted for its ability to cause serious damage and significant pathogenic variability. This study reveals the features of the high-quality genome of C. lindemuthianum. Analysis showed improvements over the first assembly, with the refined genome having 119 scaffolds, ten times fewer than the first, and a 19% increase in gene number. The effector candidates increased by nearly 1.5 times. More than 40% of the amino acid sequences with homologs in the Pathogen-Host Interactions (PHI-base) database are linked to pathogenicity. Of 18 putative proteins identified as Chitinase-like Protein, six have a mutation in the enzyme catalytic motif, and three showed gene expression in the biotrophic phase, indicating they can act as effectors. Comparative genomic analyses with 30 other fungal species revealed that C. lindemuthianum is among the top three fungi encoding transport proteins. Seven Necrosis and Ethylene-Inducing Peptide 1 (Nep1)-Like Proteins (NLPs) are present in the C. lindemuthianum genome, but none had complete identity with the GHRHDWE conserved motif of NLPs; two were grouped with proteins that induce necrosis and may retain the capability to induce host necrosis. Colletotrichum species show a high number of secondary metabolite (SM) clusters, with C. lindemuthianum having 47 SM clusters. Approximately 60% of the C. lindemuthianum genome is composed of repetitive elements, a significantly higher proportion than in other fungi. These differences in transposable element (TE) numbers may explain why C. lindemuthianum has one of the largest genomes among the fungi analyzed. A significant portion of its genome comprises retroelements, particularly the Ty1/Copia superfamily, which accounts for 22% of the genome and represents 40% of the repetitive elements. The genomic profile features a remarkably high RIP-affected genomic proportion of 54.77%, indicating substantial RIP activity within this species. This high-quality genome of C. lindemuthianum, a significant pathogen in common bean cultivation, will support future research into this pathosystem, fostering a deeper understanding of the interaction between the fungus and its host.

Understanding the interactions between fungal plant pathogens and host roots is crucial for developing effective disease management strategies. This study investigates the molecular mechanisms underpinning the chemotropic responses of the maize anthracnose fungus Colletotrichum graminicola to maize root exudates. Combining the generation of a deletion mutant with monitoring of disease symptom development and detailed analysis of chemotropic growth using a 3D-printed device, we identify the 7-transmembrane G-protein coupled receptor (GPCR) CgSte3 as a key player in sensing both plant-derived class III peroxidases and diterpenoids. Activation of CgSte3 initiates signaling through CgSo, a homolog to the Cell Wall Integrity Mitogen-Activated Protein Kinase (CWI MAPK) pathway scaffold protein identified in other filamentous fungi, facilitating the pathogen's growth towards plant defense molecules. The NADPH oxidase CgNox2 is crucial for peroxidase sensing but not for diterpenoid detection. These findings reveal that CgSte3 and CWI MAPK pathways are central to C. graminicola's ability to hijack plant defense signals, highlighting potential targets for controlling maize anthracnose.

Olive tree anthracnose is caused by infection with Colletotrichum fungi, which in Portugal are mostly C. nymphaeae, C. godetiae, and C. gloeosporioides s.s. Severe economic losses are caused by this disease that would benefit from a greener and more efficient alternative to the present agrochemical methods. Yeasts are serious candidates for pre-harvest/in field biocontrol of fungal infections. This work identified the yeast Wickerhamomyces anomalus as a strong antagonizer of the three fungi and studied in vitro this ability and its associated mechanisms. Antagonism was shown to not depend on the secretion of volatile compounds (VOCs), or siderophores or any other agar-diffusible compound, including hydrolytic enzymes. Rather, it occurred mostly in a cell-to-cell contact dependent manner. This was devised through detailed microscopic assessment of yeast-fungus cocultures. This showed that W. anomalus antagonism of the three Colletotrichum proceeded through (i) the adhesion of yeast cells to the phytopathogen hyphae, (ii) the secretion of a viscous extracellular matrix, and (iii) the emptying of the hyphae. Yeasts ultimately putatively feed on hyphal contents, which is supported by light microscopy observation of MB and PI co-culture-stained samples. Accordingly, numerous W. anomalus cells were observed packing inside C. godetiae emptied hyphae. This behaviour can be considered microbial predation and classified as necrotrophic mycoparasitism, more explicitly in the case of C. godetiae. The results support the prospect of future application of W. anomalus as a living biofungicide/BCA in the preharvest control of olive anthracnose.

The natural system at Great Salt Lake, Utah, USA was augmented by the construction of a rock-filled railroad causeway in 1960, creating two lakes at one site. The north arm is sequestered from the mountain snowmelt inputs and thus became saturated with salts (250-340 g/L). The south arm is a flourishing ecosystem with moderate salinity (90-190 g/L) and a significant body of water for ten million birds on the avian flyways of the western US who engorge themselves on the large biomass of brine flies and shrimp. The sediments around the lake shores include calcium carbonate oolitic sand and clay, and further away from the saltwater margins, a zone with less saline soil. Here a small number of plants can thrive, including Salicornia and Sueda species. At the north arm at Rozel Point, halite crystals precipitate in the salt-saturated lake water, calcium sulfate precipitates to form gypsum crystals embedded in the clay, and high molecular weight asphalt seeps from the ground. It is an ecosystem with gradients and extremes, and fungi are up to the challenge. We have collected data on Great Salt Lake fungi from a variety of studies and present them here in a spatial survey. Combining knowledge of cultivation studies as well as environmental DNA work, we discuss the genera prevalent in and around this unique ecosystem. A wide diversity of taxa were found in multiple microniches of the lake, suggesting significant roles for these genera: Acremonium, Alternaria, Aspergillus, Cladosporium, Clydae, Coniochaeta, Cryptococcus, Malassezia, Nectria, Penicillium, Powellomyces, Rhizophlyctis, and Wallemia. Considering the species present and the features of Great Salt Lake as a terminal basin, we discuss of the possible roles of the fungi. These include not only nutrient cycling, toxin mediation, and predation for the ecosystem, but also roles that would enable other life to thrive in the water and on the shore. Many genera that we discovered may help other organisms in alleviating salinity stress, promoting growth, or affording protection from dehydration. The diverse taxa of Great Salt Lake fungi provide important benefits for the ecosystem.

Carotenoids produced by bacteria, yeasts, algae and plants inactivate Free Radicals (FR). However, FR may inactivate carotenoids and even turn them into free radicals. Oxidative metabolism is a source of the highly motile Reactive Oxygen Species (ROS). To evaluate carotenoid interactions with ROS, the yeast Rhodotorula mucilaginosa was grown in dextrose (YPD), a fermentative substrate where low rates of oxygen consumption and low carotenoid expression were observed, or in lactate (YPLac), a mitochondrial oxidative-phosphorylation (OxPhos) substrate, which supports high respiratory activity and carotenoid production. ROS were high in YPLac-grown cells and these were unmasked by the carotenoid production-inhibitor diphenylamine (DPA). In contrast, in YPD-grown cells ROS were almost absent. It is proposed that YPLac cells are under oxidative stress. In addition, YPLac-grown cells were more sensitive than YPD-grown cells to menadione (MD), a FR-releasing agent. To test whether carotenoids from cells grown in YPLac had been modified by ROS, carotenoids from each, YPD- and YPLac-grown cells were isolated and added back to cells, evaluating protection from MD. Remarkably, carotenoids extracted from cells grown in YPLac medium inhibited growth, while in contrast extracts from YPD-grown cells were innocuous or mildly protective. Results suggest that carotenoid-synthesis in YPLac-cells is a response to OxPhos-produced ROS. However, upon reacting with FR, carotenoids themselves may be inactivated or even become prooxidant themselves.