Ampelomyces strains isolated from diverse powdery mildew hosts in Japan: Their phylogeny and mycoparasitic activity, including timing and quantifying mycoparasitism of Pseudoidium neolycopersici on tomato

Analysis of structural and metabolic changes in surface microorganisms following powdery mildew infection in wheat and assessment of their potential function in biological control

Powdery mildew is a highly destructive disease that greatly reduces both the yield and quality of wheat. As there is limited research on changes in microorganism community caused by powdery mildew infection in different tissue parts, especially after spike infection, this study aimed to examine surface microorganisms in infected and healthy wheat plants. Samples were collected from the leaves and spikes, and the number of operational taxonomic units (OTUs), diversity index, abundance, and metabolic changes of the surface microbial community were analysed using 16S rRNA amplicon sequencing technology. Through the identification of surface microbial community in different tissues, 24 phyla were identified in the leaves, and 20 phyla were identified in the spikes. The dominant bacterial phyla observed were Proteobacteria and Bacteroidetes. At the genus level, 19 genera were detected in the leaves, and 11 genera were detected in the spikes. Notably, the total number of genera in the leaves exceeded that in the spikes. The dominant genera were Pseudomonas, Sphingomonas, and Pantoea. At the species level, there were 37 types identified in leaves and 35 types in spikes. The dominant bacterial species identified included Pedobacterium panaciterrae, Pseudomonas baetica, Pseudomonas rhizophaerae, and Sphingomonas aerolata. The analysis conducted in this study revealed that the incidence of powdery mildew was greater in plots situated closer to obstacles than in other plots. Notably, when wheat was infected with powdery mildew, the results indicated that surface microorganisms on both leaves and spikes were significantly impacted, with the response of surface microorganisms on the spikes being more pronounced than that on the leaves. Different from the response of microorganisms on the leaf surface, after infection with powdery mildew, the pathway changes of microorganisms on the spike surface are mainly metabolic regulation. These research results provide theoretical support for the prevention and control of powdery mildew in wheat crops.

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

Mangrove endophytic fungi: Biocontrol potential against Rhizoctonia solani and biofertilizers for fragrant rice cultivation

The mangrove ecosystem has emerged as a fascinating source for exploring novel bioresources which have multiple applications in modern agriculture. This study evaluates the potential applications of mangrove endophytic fungi (MEF), such as biocontrol agents against Rhizoctonia solani and as biofertilizers for improving the yield of fragrant rice variety Malaysian Rice Quality 76 (MRQ76). Through the antagonism assays, it is observed that among the 14 MEF studied, 4 fungal isolates (Colletotrichum sp. MEFN02, Aspergillus sp. MEFN06, Annulohypoxylon sp. MEFX02 and Aspergillus sp. MEFX10) exhibited promising antagonistic effect against the pathogen R. solani compared to the chemical fungicide (Benomyl). These isolates also revealed significant production of enzymes, phytochemicals, indoleacetic acid (40.96 mg/mL) and ammonia (32.54 mg/mL) and displayed tolerance to salt and temperature stress up to 2000 mM and >40 °C respectively. Furthermore, employing the germination and pathogenicity test, inoculation of these endophytes showed lower percentage of disease severity index (DSI%) against R. solani, ranging from (24 %-46 %) in MRQ76 rice seedlings. The in-vivo experiments of soil and seed inoculation methods conducted under greenhouse conditions revealed that these endophytes enhanced plant growth (8-15 % increase) and increased crop yield (≥50 %) in comparison to control treatments. The current findings provide valuable insights into eco-friendly, cost-effective and sustainable alternatives for addressing R. solani infection and improving the agronomic performance of the fragrant rice cultivar MRQ76, contributing to food security.

What is the role of the nitrate reductase (euknr) gene in fungi that live in nitrate-free environments? A targeted gene knock-out study in Ampelomyces mycoparasites

Mycoparasitic fungi can be utilized as biocontrol agents (BCAs) of many plant pathogens. Deciphering the molecular mechanisms of mycoparasitism may improve biocontrol efficiency. This work reports the first functional genetic studies in Ampelomyces, widespread mycoparasites and BCAs of powdery mildew fungi, and a molecular genetic toolbox for future works. The nitrate reductase (euknr) gene was targeted to reveal the biological function of nitrate assimilation in Ampelomyces. These mycoparasites live in an apparently nitrate-free environment, i.e. inside the hyphae of powdery mildew fungi that lack any nitrate uptake and assimilation system. Homologous recombination-based gene knock-out (KO) was applied to eliminate the euknr gene using Agrobacterium tumefaciens-mediated transformation. Efficient KO of euknr was confirmed by PCR, and visible phenotype caused by loss of euknr was detected on media with different nitrogen sources. Mycoparasitic ability was not affected by knocking out euknr as a tested transformant readily parasitized Blumeria graminis and Podosphaera xanthii colonies on barley and cucumber, respectively, and the rate of mycoparasitism did not differ from the wild type. These results indicate that euknr is not involved in mycoparasitism. Dissimilatory processes, involvement in nitric oxide metabolism, or other, yet undiscovered processes may explain why a functional euknr is maintained in Ampelomyces.

The "Bipartite" Structure of the First Genome of Ampelomyces quisqualis, a Common Hyperparasite and Biocontrol Agent of Powdery Mildews, May Point to Its Evolutionary Origin from Plant Pathogenic Fungi

Powdery mildews are among the most important plant pathogens worldwide, which are often attacked in the field by mycoparasitic fungi belonging to the genus Ampelomyces. The taxonomy of the genus Ampelomyces is unresolved, but well-supported molecular operational taxonomic units were repeatedly defined suggesting that the genus may include at least four to seven species. Some Ampelomyces strains were commercialized as biocontrol agents of crop pathogenic powdery mildews. However, the genomic mechanisms underlying their mycoparasitism are still poorly understood. To date, the draft genome of a single Ampelomyces strain, designated as HMLAC 05119, has been released. We report a high-quality, annotated hybrid draft genome assembly of A. quisqualis strain BRIP 72107, which, based on phylogenetic analyses, is not conspecific with HMLAC 05119. The constructed genome is 40.38 Mb in size, consisting of 24 scaffolds with an N50 of 2.99 Mb and 96.2% completeness. Our analyses revealed "bipartite" structure of Ampelomyces genomes, where GC-balanced genomic regions are interspersed by longer or shorter stretches of AT-rich regions. This is also a hallmark of many plant pathogenic fungi and provides further evidence for evolutionary affinity of Ampelomyces species to plant pathogenic fungi. The high-quality genome and annotation produced here provide an important resource for future genomic studies of mycoparasitisim to decipher molecular mechanisms underlying biocontrol processes and natural tritrophic interactions.