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The roots of the medicinal plant Codonopsis pilosula (Franch.) Nannf (C. pilosula) possess most medicinal supplements. In current research on C. pilosula root endophytes were isolated, identified, and evaluated for their antimicrobial activity against human pathogens such as Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Salmonella typhi , and Pseudomonas aeruginosa and the fungi Candida albicans and Aspergillus niger. Endophytes C.P-8 and C.P-20 exhibited very significant antimicrobial activity, the secondary metabolite of C.P-8 registered at retention time 24.075 by HPLC analysis. Significant minimum inhibitory concentration (MIC) of C.P-8 was exhibited at 250 µg/ml against S. aureus and 500 µg/ml against B. subtilis. Qualitative, quantitative analyses, and partial purification of enzymes and purity was analysed by molecular weight determined by SDS‒PAGE of enzymes produced by C.P-20, amylase—64 kDa, protease—64 kDa, chitinase—30 kDa, and cellulase—54 kDa. Optimum pH and temperature of the partially purified enzymes, was carried out. The partially purified enzymes from C.P-20 displayed maximum activity at pH 6–7 and temperatures of 40°C–45°C. Moreover, the above endophytes will be useful tools for producing active enzymes and active bioantimicrobial agents against human pathogens. [ABSTRACT FROM AUTHOR]

Model of 2′-deoxyguanosine involvement in plant immune response. Endophytic fungus-derived 2-dG directly activates ET signaling, EIT and PTI. Moreover, pathogen invasion induces the expression of the plant 2-dG biosynthesis gene VEN4 and promotes 2-dG accumulation in plant leaves. However, 2-dG-mediated plant resistance against Pst DC3000 is conferred in an ET-, NPR1 -, PRR/coreceptor- and P2K1 -dependent manner. [Display omitted] • We identified for the first time that nucleoside 2′-deoxyguanosine from endophytic fungal metabolites can effectively stimulate classical immune responses in plants. • We demonstrated that 2-dG-induced plant resistance depends on salicylic acid (SA) receptor NPR1 (but not SA), ethylene (ET) signaling, pattern-recognition receptors/coreceptors (PRRs/coreceptors) and the ATP receptor P2K1. • We provide the first demonstration that VEN4 is 2-dG biosynthesis gene and involved in pathogen-induced 2-dG accumulation, VEN4 also plays an essential role for plant immunity. Beneficial microorganisms play essential roles in plant growth and induced systemic resistance (ISR) by releasing signaling molecules. Our previous study obtained the crude extract from beneficial endophyte Paecilomyces variotii , termed ZNC (ZhiNengCong), which significantly enhanced plant resistance to pathogen even at 100 ng/ml. However, the immunoreactive components of ZNC remain unclear. Here, we further identified one of the immunoreactive components of ZNC is a nucleoside 2′-deoxyguanosine (2-dG). This paper intends to reveal the molecular mechanism of microbial-derived 2′-deoxyguanosine (2-dG) in activating plant immunity, and the role of plant-derived 2-dG in plant immunity. The components of ZNC were separated using a high-performance liquid chromatography (HPLC), and 2-dG is identified using a HPLC–mass spectrometry system (LC-MS). Transcriptome analysis and genetic experiments were used to reveal the immune signaling pathway dependent on 2-dG activation of plant immunity. This study identified 2′-deoxyguanosine (2-dG) as one of the immunoreactive components from ZNC. And 2-dG significantly enhanced plant pathogen resistance even at 10 ng/ml (37.42 nM). Furthermore, 2-dG-induced resistance depends on NPR1, pattern-recognition receptors/coreceptors, ATP receptor P2K1 (DORN1), ethylene signaling but not salicylic acid accumulation. In addition, we identified Arabidopsis VENOSA4 (VEN4) was involved in 2-dG biosynthesis and could convert dGTP to 2-dG, and vne4 mutant plants were more susceptible to pathogens. In summary, microbial-derived 2-dG may act as a novel immune signaling molecule involved in plant-microorganism interactions, and VEN4 is 2-dG biosynthesis gene and plays a key role in plant immunity. [ABSTRACT FROM AUTHOR]

Background: Plant viruses cause severe economic losses in agricultural production. An ultrahigh activity plant immune inducer (i.e., ZhiNengCong, ZNC) was extracted from endophytic fungi, and it could promote plant growth and enhance resistance to bacteria. However, the antiviral function has not been studied. Our study aims to evaluate the antiviral molecular mechanisms of ZNC in tobacco. Results: Here, we used Potato X virus (PVX), wild-type tobacco and NahG transgenic tobacco as materials to study the resistance of ZNC to virus. ZNC exhibited a high activity in enhancing resistance to viruses and showed optimal use concentration at 100–150 ng/mL. ZNC also induced reactive oxygen species accumulation, increased salicylic acid (SA) content by upregulating the expression of phenylalanine ammonia lyase (PAL) gene and activated SA signaling pathway. We generated transcriptome profiles from ZNC-treated seedlings using RNA sequencing. The first GO term in biological process was positive regulation of post-transcriptional gene silencing, and the subsequent results showed that ZNC promoted RNA silencing. ZNC-sprayed wild-type leaves showed decreased infection areas, whereas ZNC failed to induce a protective effect against PVX in NahG leaves. Conclusion: All results indicate that ZNC is an ultrahigh-activity immune inducer, and it could enhance tobacco resistance to PVX at low concentration by positively regulating the RNA silencing via SA pathway. The antiviral mechanism of ZNC was first revealed in this study, and this study provides a new antiviral bioagent. [ABSTRACT FROM AUTHOR]