A Novel Partitivirus that Confers Hypovirulence on Plant Pathogenic Fungi

Members of the family Partitiviridae have bisegmented double-stranded RNA (dsRNA) genomes and are not generally known to cause obvious symptoms in their natural hosts. An unusual partitivirus, Sclerotinia sclerotiorum partitivirus 1 (SsPV1/WF-1), conferred hypovirulence on its natural plant-pathogenic fungal host, Sclerotinia sclerotiorum strain WF-1. Cellular organelles, including mitochondria, were severely damaged. Hypovirulence and associated traits of strain WF-1 and SsPV1/WF-1 were readily cotransmitted horizontally via hyphal contact to different vegetative compatibility groups of S. sclerotiorum and interspecifically to Sclerotinia nivalis and Sclerotinia minor. S. sclerotiorum strain 1980 transfected with purified SsPV1/WF-1 virions also exhibited hypovirulence and associated traits similar to those of strain WF-1. Moreover, introduction of purified SsPV1/WF-1 virions into strain KY-1 of Botrytis cinerea also resulted in reductions in virulence and mycelial growth and, unexpectedly, enhanced conidial production. However, virus infection suppressed hyphal growth of most germinating conidia of B. cinerea and was eventually lethal to infected hyphae, since very few new colonies could develop following germ tube formation. Taken together, our results support the conclusion that SsPV1/WF-1 causes hypovirulence in Sclerotinia spp. and B. cinerea. Cryo-EM (cryo-electron microscopy) reconstruction of the SsPV1 particle shows that it has a distinct structure with similarity to the closely related partitiviruses Fusarium poae virus 1 and Penicillium stoloniferum virus F. These findings provide new insights into partitivirus biological activities and clues about molecular interactions between partitiviruses and their hosts. IMPORTANCE: Members of the Partitiviridae are believed to occur commonly in their phytopathogenic fungal and plant hosts. However, most partitiviruses examined so far appear to be associated with latent infections. Here we report a partitivirus, SsPV1/WF-1, that was isolated from a hypovirulent strain of Sclerotinia sclerotiorum and describe its biological and molecular features. We have demonstrated that SsPV1 confers hypovirulence. Furthermore, SsPV1 can infect and cause hypovirulence in Botrytis cinerea. Our study also suggests that SsPV1 has a vigorous ability to proliferate and spread via hyphal contact. SsPV1 can overcome vegetative incompatibility barriers and can be transmitted horizontally among different vegetative compatibility groups of S. sclerotiorum, even interspecifically. Cryo-EM reconstruction of SsPV1 shows that it has a distinct structure with similarity to closely related partitiviruses. Our studies exploit a novel system, SsPV1 and its hosts, which can provide the means to explore the mechanisms by which partitiviruses interact with their hosts

Immunogenicity and therapeutic effects of a Mycobacterium tuberculosis rv2190c DNA vaccine in mice

The Excel data file [FOLT] Figshare, [DOI: 10.6084/m9.figshare.4668148 and https://figshare.com/s/bd46c22986c673579bb6 ] includes all datasets supporting the conclusions of this article: IFN-Îł in spleen lymphocyte culture supernatants, IL-4 in spleen lymphocyte culture supernatants, CD4+ T cell subsets expressing intracellular IFN-Îł or IL-4, CFU in the lungs and spleens.. (XLS 143 kb

Genome and transcriptome sequences reveal the specific parasitism of the nematophagous Purpureocillium lilacinum 36-1

Purpureocillium lilacinum is a promising nematophagous ascomycete able to adapt diverse environments and it is also an opportunistic fungus that infects humans. A microbial inoculant of P. lilacinum has been registered to control plant parasitic nematodes. However, the molecular mechanism of the toxicological processes is still unclear because of the relatively few reports on the subject. In this study, using Illumina paired-end sequencing, the draft genome sequence and the transcriptome of P. lilacinum strain 36-1 infecting nematode-eggs were determined. Whole genome alignment indicated that P. lilacinum 36-1 possessed a more dynamic genome in comparison with P. lilacinum India strain. Moreover, a phylogenetic analysis showed that the P. lilacinum 36-1 had a closer relation to entomophagous fungi. The protein-coding genes in P. lilacinum 36-1 occurred much more frequently than they did in other fungi, which was a result of the depletion of repeat-induced point mutations (RIP). Comparative genome and transcriptome analyses revealed the genes that were involved in pathogenicity, particularly in the recognition, adhesion of nematode-eggs, downstream signal transduction pathways and hydrolase genes. By contrast, certain numbers of cellulose and xylan degradation genes and a lack of polysaccharide lyase genes showed the potential of P. lilacinum 36-1 as an endophyte. Notably, the expression of appressorium-formation and antioxidants-related genes exhibited similar infection patterns in P. lilacinum strain 36-1 to those of the model entomophagous fungi Metarhizium spp. These results uncovered the specific parasitism of P. lilacinum and presented the genes responsible for the infection of nematode-eggs

Dihydroxyacetone of wheat root exudates serves as an attractant for Heterodera avenae.

Heterodera avenae, as an obligate endoparasite, causes severe yield loss in wheat (Triticum aestivum). Investigation on the mechanisms how H. avenae perceives wheat roots is limited. Here, the attractiveness of root exudates from eight plant genotypes to H. avenae were evaluated on agar plates. Results showed that the attraction of H. avenae to the root exudates from the non-host Brachypodium distachyon variety Bd21-3 was the highest, approximately 50 infective second-stage juveniles (J2s) per plate, followed by that from three H. avenae-susceptible wheat varieties, Zhengmai9023, Yanmai84 and Xiangmai25, as well as the resistant one of Xinyuan958, whereas the lowest attractive activity was observed in the two H. avenae-resistant wheat varieties, Xianmai20 (approximately 12 J2s/plate) and Liangxing66 (approximately 11 J2s/plate). Then Bd21-3, Zhengmai9023 and Heng4399 were selected for further assays as their different attractiveness and resistance to H. avenae, and attractants for H. avenae in their root exudates were characterized to be heat-labile and low-molecular compounds (LM) by behavioral bioassay. Based on these properties of the attractants, a principle of identifying attractants for H. avenae was set up. Then LM of six root exudates from the three plants with and without heating were separated and analyzed by HPLC-MS. Finally, dihydroxyacetone (DHA), methylprednisolone succinate, embelin and diethylpropionin in the root exudates were identified to be putative attractants for H. avenae according to the principle, and the attraction of DHA to H. avenae was validated by behavioral bioassay on agar. Our study enhances the recognition to the orientation mechanism of H. avenae towards wheat roots

First-Principles Study of Gas Molecule Adsorption on C-doped Zigzag Phosphorene Nanoribbons

Phosphorene, due to its large surface-to-volume ratio and high chemical activity, shows potential application for gas sensing. In order to explore its sensing performance, we have performed the first-principles calculations based on density functional theory (DFT) to investigate the perfect and C-doped zigzag phosphorene nanoribbons (C-ZPNRs) with a series of small gas molecules (NH3, NO, NO2, H2, O2, CO, and CO2) adsorbed. The calculated results show that NH3, CO2, O2 gas molecules have relatively larger adsorption energies than other gas molecules, indicating that phosphorene is more sensitive to these gas molecules. For C-ZPNRs configuration, the adsorption energy of NO and NO2 increase and that of other gas molecules decrease. Interestingly, the adsorption energy of hydrogen is −0.229 eV, which may be suitable for hydrogen storage. It is hoped that ZPNRs may be a good sensor for (NH3, CO2 and O2) and C-ZPNRs may be useful for H2 storage

Transcriptome Analysis of Eggplant Root in Response to Root-Knot Nematode Infection

Eggplant (Solanum melongena L.), which belongs to the Solanaceae family, is an important vegetable crop. However, its production is severely threatened by root-knot nematodes (RKNs) in many countries. Solanum torvum, a wild relative of eggplant, is employed worldwide as rootstock for eggplant cultivation due to its resistance to soil-borne diseases such as RKNs. In this study, to identify the RKN defense mechanisms, the transcriptomic profiles of eggplant and Solanum torvum were compared. A total of 5360 differentially expressed genes (DEGs) were identified for the response to RKN infection. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis showed that these DEGs are mainly involved in the processes of response to stimulus, protein phosphorylation, hormone signal transduction, and plant-pathogen interaction pathways. Many phytohormone-related genes and transcription factors (MYB, WRKY, and NAC) were differentially expressed at the four time points (ck, 7, 14, and 28 days post-infection). The abscisic acid signaling pathway might be involved in plant-nematode interactions. qRT-PCR validated the expression levels of some of the DEGs in eggplant. These findings demonstrate the nematode-induced expression profiles and provide some insights into the nematode resistance mechanism in eggplant

The electronic and optical properties of InSe/ZnO van der Waals heterojunction:First principles study

The efficient, simple and low-cost photocatalysts has become a hot topic in the field of photocatalysis, ZnO has attracted the attention of researchers due to its high photocatalytic efficiency. Although, the broad band gap of around 3.4 eV in ZnO greatly limits its optical absorption efficiency. Based on this, two types of InSe/ZnO heterojunction models with different configurations are constructed, their electronic and optical properties are studied through first principles calculations. The results indicate that the II InSe/ZnO heterojunction has a band gap of 1.84 eV, which compensates for the shortcomings of ZnO monolayer broad band gap absorption of visible light and the difficulty of InSe monolayer in participating in water splitting oxidation reactions. The construction of heterojunctions using InSe and ZnO significantly improves the light absorption efficiency, especially in the visible spectral region, compared to ZnO monolayers, accelerating the generation and migration efficiency of photo generated electrons, thereby improving the catalytic efficiency of ZnO