Ralstonia solanacearum strain PRS-84 used in this study was isolated from diseased Pogostemon cablin plants in our previous study.The competent cells of R.solanacearum strain PRS-84 were transformed by electroporation with Tn5 transposon and then were plated on TTC agar plates containing kanamycin to select for kanamycin-resistant colonies.The detection of kanamycin-resistant gene in kanamycin-resistant colonies was performed by PCR.Further,the flanking fragments of Tn5 transposon insertion site in the mutants were amplified by inverse PCR,and the flanking fragments were sequenced and analyzed.The results indicated that the kanamycin-resistant colonies were obtained in the transformation experiment of R.solanacearum strain PRS-84 by electroporation with Tn5 transposon.A specific band of approximately 700 bp was amplified by PCR from kanamycin-resistant colonies.The flanking sequences of Tn5 transposon insertion site in the transformants were obtained by inverse PCR.After sequencing and sequence analysis of Tn5 transposon insertion site in mutants,we preliminarily speculated that the Tn5 transposon inserted in the typ A gene,rec O gene and gid A gene in three mutants,respectively.A random mutagenesis system of R.solanacearum strain PRS-84 by electroporation with Tn5 transposon has been established,and the Tn5 insertion mutants have been obtained.This study might facilitate the creation of mutant library and the discovery of the virulence gene of R.solanacearum isolated from P.cablin.
DNA Transposable Elements ; Electroporation ; Genes, Bacterial ; Mutagenesis, Insertional ; Pogostemon ; microbiology ; Ralstonia solanacearum ; genetics ; Virulence

The culture filtrate of Lentinula edodes shows potent antimicrobial activity against the plant pathogenic bacteria Ralstonia solanacearum. Bioassay-guided fractionation was conducted using Diaion HP-20 column chromatography, and the insoluble active compound was not adsorbed on the resin. Further fractionation by high-performance liquid chromatography (HPLC) suggested that the active compounds were organic acids. Nine organic acids were detected in the culture filtrate of L. edodes; oxalic acid was the major component and exhibited antibacterial activity against nine different phytopathogenic bacteria. Quantitative analysis by HPLC revealed that the content of oxalic acid was higher in the water extract from spent mushroom substrate than in liquid culture. This suggests that the water extract of spent L. edodes substrate is an eco-friendly control agent for plant diseases.
Agaricales ; Bacteria* ; Chromatography ; Chromatography, High Pressure Liquid ; Chromatography, Liquid ; Lentinula* ; Oxalic Acid* ; Plant Diseases ; Plants ; Ralstonia solanacearum ; Shiitake Mushrooms* ; Water

Culture filtrates of six different edible mushroom species were screened for antimicrobial activity against tomato wilt bacteria Ralstonia solanacearum B3. Hericium erinaceus, Lentinula edodes (Sanjo 701), Grifola frondosa, and Hypsizygus marmoreus showed antibacterial activity against the bacteria. Water, n-butanol, and ethyl acetate extracts of spent mushroom substrate (SMS) of H. erinaceus exhibited high antibacterial activity against different phytopathogenic bacteria: Pectobacterium carotovorum subsp. carotovorum, Agrobacterium tumefaciens, R. solanacearum, Xanthomonas oryzae pv. oryzae, X. campestris pv. campestris, X. axonopodis pv. vesicatoria, X. axonopodis pv. citiri, and X. axonopodis pv. glycine. Quantitative real-time PCR revealed that water extracts of SMS (WESMS) of H. erinaceus induced expressions of plant defense genes encoding beta-1,3-glucanase (GluA) and pathogenesis-related protein-1a (PR-1a), associated with systemic acquired resistance. Furthermore, WESMS also suppressed tomato wilt disease caused by R. solanacearum by 85% in seedlings and promoted growth (height, leaf number, and fresh weight of the root and shoot) of tomato plants. These findings suggest the WESMS of H. erinaceus has the potential to suppress bacterial wilt disease of tomato through multiple effects including antibacterial activity, plant growth promotion, and defense gene induction.
1-Butanol ; Agaricales* ; Agrobacterium tumefaciens ; Bacteria ; Glycine ; Grifola ; Lycopersicon esculentum* ; Oryza ; Pectobacterium carotovorum ; Plants ; Ralstonia solanacearum ; Real-Time Polymerase Chain Reaction ; Seedlings ; Shiitake Mushrooms ; Water* ; Xanthomonas

Fourteen compounds were isolated from Dalbergia odoriferae and purified by repeated column chromatography on silica and sephadex LH-20 gel and structurally identified by spectral analysis. These compounds were identified as 4, 9-dimethoxy-3-hydroxypterocarpan (1), medicarpin (2), 2', 4', 5-trihydroxy-7-methoxyisoflavone (3), 2', 3', 7-trihydroxy-4'-methoxyisoflavan (4), formononetin (5), 3, 8-dihydroxy-9-methoxypterocarpan (6), koparin (7), 3-hydroxy-9-methoxypterocarp-6a-ene (8), 2'-hydroxyformononetin (9), stevenin (10), 2', 7-dihydroxy-4', 5'-dimethoxyisoflavone (11), lyoniresinol (12), 2, 4-dihydroxy-5-methoxy-benzophenone (13) and neokhriol A (14). Compounds 1, 3, 4, 6, 8, 12 and 14 were isolated from this plant for the first time. Antibacterial activity assay showed that compound 4 had inhibitory effect on Ralstonia solanacearum.
Anisoles ; chemistry ; isolation & purification ; pharmacology ; Anti-Bacterial Agents ; chemistry ; isolation & purification ; pharmacology ; Benzophenones ; chemistry ; isolation & purification ; pharmacology ; Chromatography ; methods ; Dalbergia ; chemistry ; Dextrans ; Gels ; Isoflavones ; chemistry ; isolation & purification ; pharmacology ; Microbial Sensitivity Tests ; Naphthalenes ; chemistry ; isolation & purification ; pharmacology ; Plant Extracts ; chemistry ; isolation & purification ; pharmacology ; Pterocarpans ; chemistry ; isolation & purification ; pharmacology ; Ralstonia solanacearum ; drug effects ; growth & development ; Silica Gel