Background: Beauveria bassiana (B. bassiana) is a famous entomopathogenic fungus that could parasitize on hundreds of insect species, which are being used as an environmentally friendly mycoinsecticide. Nevertheless, the possible effect of genetic diversity of these B. bassiana isolates from different hosts on virulence has not been explored before. In order to explore that issue, we compared the genome sequences among seventeen B. bassiana isolates from 17 different insects using whole genome re-sequencing, with B. bassiana strain ARSEF 2860 as the reference genome. Results: There were a total of 10,098 missense mutated genes, 720 positively selected genes were identified in 17 strains of B. bassiana. Among these, two genes with high frequency mutations encode the toxin-producing non-ribosomal peptide synthase (NRPS) protein. Seven genes undergoing positive selection were enriched in the two-component signaling pathway that is known to regulate the fungal toxicity. In addition, the domain changes of three positively selected genes are also directly related to the virulence plasticity. Besides, the functional categorization of mutated genes showed that most of them involved in the biological functions of toxic proteins involved in. Conclusions: Based on our data, our results indicate that several mutated genes and positively selected genes may underpin virulence of B. bassiana towards hosts during infection process, which provide an insight into the potential effects of natural variation on the virulence of B. bassiana, which will be useful in screening out potential virulence factors in B. bassiana.

Rhizoctonia solani is an important soil-borne fungal pathogen that causes serious diseases on many agricultural crops and vegetables. Here, we report a complete genome assembly of R. solani AG4 (assembly: 45.47 Mb; contig N₅₀: 1.56 Mb), using a combination of Illumina paired-end and PacBio long-read sequencing data. A total of 267 noncoding RNAs and 11,592 genes were predicted, including 109 genes associated with carbohydrate-active enzymes and 2,488 genes involved in host-pathogen interactions. The complete genome of R. solani AG4 represents a valuable base for studying interactions between host plants and pathogenic fungi and to search for potential antimicrobial targets. [ ] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

The bacterial community of rhizosphere soil maintains soil properties, regulates the microbiome, improves productivity, and sustains agriculture. However, the structure and function of bacterial communities have been interrupted or destroyed by unreasonable agricultural practices, especially the excessive use of chemical fertilizers. Microbial inoculants, regarded as harmless, effective, and environmentally friendly amendments, are receiving more attention. Herein, the effects of three microbial inoculants, inoculant M and two commercial inoculants (A and S), on bacterial communities of maize rhizosphere soil under three nitrogen application rates were compared. Bacterial communities treated with the inoculants were different from those of the non-inoculant control. The OTU (operational taxonomic unit) numbers and alpha diversity indices were decreased by three inoculants, except for the application of inoculant M in CF group. Beta diversity showed the different structures of bacterial communities changed by three inoculants compared with control. Furthermore, key phylotypes analyses exhibited the differences of biomarkers between different treatments visually. Overall, inoculant M had shared and unique abilities of regulating bacterial communities compared with the other two inoculants by increasing potentially beneficial bacteria and decreasing the negative. This work provides a theoretical basis for the application of microbial inoculants in sustainable agriculture.

Mycoviruses can spread interspecifically and intraspecifically in plant pathogenic fungi, as well as spreading intraspecifically in entomogenous fungi, especially Beauveria bassiana. However, whether mycoviruses are common in Beauveria spp. and can spread interspecifically between Beauveria species are unclear. Herein, four Beauveria species, but not B. bassiana, were randomly selected for double stranded RNA (dsRNA) detection. Furthermore, two previously reported dsRNA mycoviruses from B. bassiana, BbCV-2 and BbPmV-4, were used to study the interspecific transmission among B. bassiana, B. amorpha, and B. aranearum, using hyphal anastomosis and a novel insect coinfection transmission method. The results showed that dsRNA mycoviruses exist universally in Beauveria spp. and could spread interspecifically between different Beauveria species. The transmission efficiency from B. bassiana to the other two Beauveria species was significantly higher than that of the reverse transmission. Both viruses could stably and vertically spread in B. amorpha and B. aranearum, which affected their growth rate and colony morphology.