Bacterial infections of plants are widespread and highly virulent, causing serious economic losses in agricultural production worldwide. These infections become particularly prevalent during rainy weather, characterized by high humidity and low light intensity (about 2–10% of a sunny day). Here we identified a class of photosensitizers that were effective in inhibiting plant bacterial infections under rainy weather with dim light. One of these compounds, compound 1 , demonstrated exceptional efficacy by eliminating more than 4 logs (99.99%) of either Xanthomonas perforans or Xanthomonas citri subsp. citri (Xcc) strain at a concentration of 6.25 μM under rainy weather conditions with a light exposure of 28.51 J/cm 2 . For Clavibacter michiganensis ( Cm ), compound 1 demonstrated a comparable bactericidal effect at a lower concentration of 3.13 μM. Furthermore, compound 1 was effective in controlling plant leaf infections during rainy weather. Moreover, compound 1 exhibited a potent inhibitory effect on the biofilms pertinent to tomato spot disease and citrus canker under natural illumination on rainy days. Additionally, compound 1 displayed remarkable resilience to rain-wash on plant leaves, retaining 41.20% of its initial concentration following exposure to three simulated rain events. These findings provide a new strategy for plant pathogen disease management highlight its feasibility even during rainy weather.
Shihao Nan,Xinmiao Ren,Mengshi Xiao,Lin Zhu,Haijin Mou,Ningyang Li,Rong Li,Shaoping Nie,Xiaodan Fu
The deoxyhexose sugar l -fucose and fucosylated oligosaccharides (FCO) are essential for various biological processes in human body and associated gut microbiota. Bacterial exopolysaccharides offer a promising new source for preparing functional oligosaccharides. Here, FCO were obtained through acidolysis of fucose-containing exopolysaccharides with a molecular weight of 5.9 × 10 3 kDa, derived from Clavibacter michiganensis M2. Structural analysis revealed that the main disaccharide components of FCO exhibited a molecular weight of 326 Da and a monosaccharide composition of fucose, galactose, and glucose in a 3:1:2 ratio. Nuclear magnetic resonance indicated that the disaccharide fragments consisted of two backbones of α- Galp -(1 → 2)-α- Fucp and β- Glcp -(1 → 4)-β- Fucp , respectively. In vitro fermentation of FCO with human fecal cultures resulted in an increased abundance of Bifidobacterium and Bacteroides , and a reduction in Escherichia-Shigella and Fusobacterium . This research outlines a novel structural fucosylated oligosaccharide and its preparation method, suggesting its potential application as a promising new prebiotic.
Rhizobacterial volatile organic compounds (VOCs) play an important role in the suppression of soil-borne phytopathogens. In this study, the VOCs produced by a soil-isolate,Bacillus subtilisFA26, were evaluatedin vitrofor their antibacterial activity againstClavibacter michiganensisssp.sepedonicus(Cms), the causal agent of bacterial ring rot of potato. The VOCs emitted by FA26 inhibited the growth of Cms significantly compared with the control. Scanning and transmission electron microscopy analyses revealed distorted colony morphology and a wide range of abnormalities in Cms cells exposed to the VOCs of FA26. Varying the inoculation strategy and inoculum size showed that the production and activity of the antibacterial VOCs of FA26 were dependent on the culture conditions. Headspace solid-phase microextraction/gas chromatography–mass spectrometry analyses revealed that FA26 produced 11 VOCs. Four VOCs (benzaldehyde, nonanal, benzothiazole and acetophenone) were associated with the antibacterial activity against Cms. The results suggested that the VOCs produced by FA26 could control the causal agent of bacterial ring rot of potato. This information will increase our understanding of the microbial interactions mediated by VOCs in nature and aid the development of safer strategies for controlling plant disease.
危险品化学品经营许可证（带存储）