Mycologia最新文献

Bioherbicides are expected to be a supplement to integrated pest management, assisting in the control of problematic weed species. For instance, bioherbicides (Phoma and BioPhoma) were recently registered in Canada and the USA for the control of some perennial dicotyledonous weeds in lawns. These products are based on strains of the fungus Didymella macrostoma (syn. Phoma macrostoma) that causes white tip disease (WTD) in Canada thistle (Cirsium arvense). In this study, WTD was reported for the first time in the Russian Federation. Analysis of the internal transcribed spacer (ITS) region of nuc rDNA and secondary metabolite profiling confirmed the identity of Russian WTD isolates to Canadian biocontrol strains identified as D. macrostoma. Multilocus phylogenetic analysis based on sequencing of the ITS region, partial large subunit nuc rDNA region (28S), RNA polymerase II second largest subunit gene (rpb2), and partial β-tubulin gene (tub2) has differentiated the WTD isolates from C. arvense and D. macrostoma isolates from other plant hosts. Based on phylogenetic, morphological, and chemotaxonomic features, these WTD isolates were described as a new species named Didymella baileyae, sp. nov. This study also demonstrated the low pathogenicity of the ex-type D. baileyae isolate VIZR 1.53 to C. arvense seedlings and its asymptomatic development in the leaves of aboveground shoots. The organic extracts from mycelium and culture filtrate of D. baileyae, as well as macrocidin A and macrocidin Z, displayed phytotoxicity both to C. arvense leaves and seedlings. Macrocidin A was only detected in the naturally infected leaf tissues of C. arvense showing WTD symptoms. Macrocidins A and Z demonstrated low antimicrobial and cytotoxic activities, exhibiting no entomotoxic properties. The data obtained within this study on the pathogenicity and metabolites of D. baileyae may be important for the rational evaluation of its prospects as a biocontrol agent.

The study of myxomycete biogeography has a long-standing history and has consistently drawn scholarly interest. Nevertheless, studies focusing specifically on the spatial and temporal distribution patterns of myxomycete diversity are relatively limited, with even fewer investigating the mechanisms driving the generation and maintenance of myxomycete diversity. Therefore, this study selected two geographically distant sampling sites within northern Chinese forests to investigate myxomycete species composition, community structure, environmental drivers, and assembly patterns under geographic barriers. We established plots in the Altai Mountains (ALE) and the Greater Khingan Mountains (GKM), gathered bark and litter, and conducted 80-day moist chamber cultures of myxomycetes. Additionally, myxomycete specimens were collected in the field simultaneously to supplement the data set. This study collected 541 myxomycete specimens belonging to 73 species from 28 genera, spanning 12 families and eight orders. The ALE and the GKM had 20 identical species, accounting for 27% of the total species. Myxomycetes from both regions exhibited abundant occurrence 18 days after cultivation, with the quantity on bark substrates notably higher than on litter. Arcyria pomiformis and Comatricha elegans were the most common species in moist chamber cultures. Mantel test outcomes revealed that environmental factors had no significant impact on myxomycete community similarity between the two areas, aligning with findings from the neutral community model analysis, indicating a predominant influence of stochastic processes on myxomycete community structure in moist chamber cultures. This study represents the first application of a quantitative framework to analyze myxomycete community assembly cultivated in moist chambers.

Species in Alternaria sections Infectoriae and Pseudoalternaria are commonly isolated from agricultural crops and a variety of other plant hosts. With the increasing appreciation that species from these two sections are often the dominant taxa recovered from important cereal crops, the need for improved understanding of their biodiversity and taxonomy has grown. Given that morphological characteristics and existing molecular markers are not sufficient for distinguishing among species, we expanded the genomic resources for these sections to support research in biosystematics and species diagnostics. Whole genome assemblies for 22 strains were generated, including the first genomes from section Infectoriae or Pseudoalternaria strains sampled from Canada, which significantly increases the number of publicly released genomes, particularly for section Pseudoalternaria. We performed comprehensive phylogenomic analyses of all available genomes (n = 39) and present the first robust phylogeny for these taxa. The segregation of the two sections was strongly supported by genomewide data, and multiple lineages were detected within each section. We then provide an overview of the biosystematics of these groups by analyzing two standard molecular markers from the largest sample of section Infectoriae and Pseudoalternaria strains studied to date. The patterns of relative diversity suggest that, in many cases, multiple species described based on minor morphological differences may actually represent different strains of the same species. A list of candidate loci for development into new informative molecular markers, which are diagnostic for sections and lineages, was created from analyses of phylogenetic signals from individual genes across the entire genome.

Salinity is an abiotic factor limiting plant fitness and therefore forest crop productivity, and salt-affected areas have been expanding throughout the world. Ectomycorrhizal (ECM) fungi can improve the salt tolerance of woody plants, including Eucalyptus species To screen for salt-resistant Pisolithus albus (PA) isolates, 16 PA isolates were cultivated on modified Melin-Norkrans agar containing NaCl at concentrations of 0, 10, 20, and 30 dS m^-1. The P. albus isolate PA33 had the greatest salt resistance under 10 and 20 dS m^-1 NaCl, which are soil salinity levels in salt-affected areas of Thailand. We studied the effect of PA33 on Eucalyptus camaldulensis × E. pellita cuttings under salt stress (0 and 16 dS m^-1) for 1 month. PA enhanced the growth of the Eucalyptus seedlings, as indicated by higher relative growth rates in height and root collar diameter of inoculated seedlings compared with non-inoculated seedlings. Moreover, the inoculated seedlings had less cell damage from NaCl, as indicated by significantly lesser leaf thickness and electrolyte leakage than the controls. These findings could lead to practices conferring socioeconomic and environmental benefits, as abandoned salt-affected areas could be reclaimed using such Eucalyptus seedlings inoculated with salt-tolerant ECM fungi.

Fossils can unveil a long-vanished combination of character states that inform inferences about the timing and patterns of diversification of modern fungi. By examining the well-preserved stacked chained vesicular conidiophores developed in clusters from the basal stroma, we describe a new taxon of fossil Zygosporiaceae with a combination of characters unknown among extant taxa on compressed serrated-margined dicot leaf (cf. Fagaceae) recovered from the Siwalik sediments (Late Miocene; ca. 12-8 Ma) of Himachal Pradesh, western Himalaya. Based upon conidiophore morphology, our Siwalik fungal remains, similar to Zygosporium Mont. (Zygosporiaceae: Xylariales: Sordariomycetes), are recognized as a new fossil species, Z. stromaticum Kundu & Khan, sp. nov. Zygosporium stromaticum is the only known fossil anamorphic fungus that occurs on plant cuticles and has a cluster of stacked chained vesicular conidiophores arising from a poorly preserved basal stroma formed by irregular, thick-walled cells. Its combination of morphological characteristics is unknown in extant fungal taxa, so Z. stromaticum likely represents a new anamorphic foliicolous fungus that may now be extinct. This unique evidence may be essential for the calibration of divergence time estimations of fungal lineages.

Fusarium graminearum causes Fusarium head blight (FHB) disease in wheat worldwide. Although F. graminearum is reported to secrete several effectors, their role in virulence and pathogenicity is unknown. The study aimed at identifying candidate genes with a role in pathogenicity and virulence using two different host systems, Arabidopsis thaliana and wheat, challenged with F. graminearum TN01. Detached leaf assay and histological studies revealed the virulent nature of TN01. A genome-wide in silico search revealed several candidate genes, of which 23 genes were selected based on reproducibility. Gene expression studies by reverse transcriptase-polymerase chain reaction (RT-PCR) in leaf tissues of Arabidopsis and the two wheat genotypes, the susceptible (Sonalika) and the resistant (Nobeoka Bozu/Nobeoka), compared with mock-treated controls in a time-course study using fungal- and plant-specific genes as internal controls revealed that these genes were differentially regulated. Further, expression of these candidates in F. graminearum-inoculated Sonalika and Nobeoka spikes compared with mock-treated controls revealed their role in pathogenicity and virulence. Gene ontology studies revealed that some of these secretory proteins possessed a role in apoptosis and ceratoplatanin and KP4 killer toxin syntheses. A three-dimensional protein configuration was performed by homology modeling using trRosetta. Further, real-time quantitative PCR (RT-qPCR) studies in F. graminearum-inoculated Arabidopsis and wheat at early time points of inoculation revealed an increased expression of the majority of these genes in Sonalika, suggesting their possible role in pathogenicity, whereas low mRNA abundance was observed for 11 of these genes in the resistant genotype, Nobeoka, compared with Sonalika, indicating their role in virulence of F. graminearum.

Fungi occupy important environmental, cultural, and socioeconomic roles. However, biological research of this diverse kingdom has lagged behind that of other phylogenetic groups. This is partially the result of the notorious difficulty in culturing a diverse array of filamentous fungal species due to their (i) often unpredictable growth, (ii) unknown preferences for culturing conditions, and (iii) long incubation times compared with other microorganisms such as bacteria and yeasts. Given the complexity associated with concurrently culturing diverse fungal species, developing practical methods for preserving as many species as possible for future research is vital. The widely accepted best practice for preserving fungal tissue is the use of cryogenic biobanking at -165 C, allowing for the preservation and documentation of stable genetic lineages, thus enabling long-term diversity-centered research. Despite the extensive literature on fungal cryopreservation, substantial barriers remain for implementation of cryogenic biobanks in smaller mycological laboratories. In this work, we present practical considerations for the establishment of a fungal culture biobank, as well as provide evidence for the viability of 61 fungal genera in cryogenic storage. By providing a pragmatic methodology for cryogenically preserving and managing many filamentous fungi, we show that creating a biobank can be economical for independently owned and operated mycology laboratories, which can serve as a long-term resource for biodiversity, conservation, and strain maintenance.