RESUMEN
Endophytic bacteria, which are common in plant tissues, may help to control plant pathogens and enhance plant growth. Camellia oleifera, an oil-producing plant, is widely grown in warm, subtropical, hilly regions in China. However, C. oleifera is strongly negatively affected by C. oleifera anthracnose, which is caused by Colletetrichum fructicola. To find a suitable biocontrol agent for C. oleifera anthracnose, 41 endophytes were isolated from the stems, leaves, and roots of C. oleifera. Bacterial cultures were identified based on analyses of 16S rDNA sequences; most strains belonged to the genus Bacillus. The antagonistic effects of these strains on C. fructicola were tested in vitro. In total, 16 strains inhibited C. fructicola growth, with B. subtilis strain 1-L-29 being the most efficient. Strain 1-L-29 demonstrated antagonistic activity against C. siamense, C. asianum, Fusarium proliferatum, Agaricodochium camellia, and Pseudomonas syringae. In addition, this strain produced indole acetic acid, solubilized phosphate, grew on N-free media, and produced siderophores. To facilitate further microecological studies of this strain, a rifampicin-resistant, green fluorescent protein (GFP)-labeled strain, 1-L-29gfpr, was created using protoplast transformation. This plasmid had good segregational stability. Strain 1-L-29gfpr was re-introduced into C. oleifera and successfully colonized root, stem, and leaf tissues. This strain remained at a stable concentration in the root more than 20 d after inoculation. Fluorescence microscopic analysis showed that strain 1-L-29gfpr thoroughly colonized the root surfaces of C. fructicola as well as the root vascular tissues of Arabidopsis thaliana.
Asunto(s)
Antibacterianos/metabolismo , Bacillus subtilis/metabolismo , Camellia/crecimiento & desarrollo , Endófitos/metabolismo , Enfermedades de las Plantas/prevención & control , Raíces de Plantas/crecimiento & desarrollo , Bacillus subtilis/clasificación , Bacillus subtilis/crecimiento & desarrollo , Bacillus subtilis/aislamiento & purificación , Camellia/metabolismo , Camellia/microbiología , Endófitos/crecimiento & desarrollo , Endófitos/aislamiento & purificación , Control Biológico de Vectores , Desarrollo de la Planta , Enfermedades de las Plantas/microbiología , Raíces de Plantas/metabolismo , Raíces de Plantas/microbiologíaRESUMEN
OBJECTIVE: To explore the anti-angiogenic effects of genistein on synovium in a rat model of type II collagen-induced arthritis (CIA). METHODS: Forty SD rats were randomly divided into normal group, model group, genistein group, methotrexate (MTX) group and Gen plus MTX group with 8 rats in each group. Arthritis in rats was induced by subcutaneous injection of type II collagen combined with complete Freund's adjuvant (CFA). On the second day after the injection, 1 mL of suspension liquid of genistein (30 mg/kg body weight, once daily) and MTX (0.2 mg/kg body weight, once a week) were administered by oral gavage respectively. The rats in normal group and model group were administered with normal saline in the same volume. Synovium of knee joints and peripheral serum were collected from the CIA rats. Microvessel density in synovium (MVD) was detected by immunohistochemical method and serum vascular endothelial growth factor (VEGF) and matrix metallopeptidase (MMP)-1, 2 and 9 levels were detected by using Western blotting. RESULTS: Arthritis index score, paw volume of rats in the model group were significantly higher than those in the normal group (P<0.05), which suggested that a model of CIA induced by injection of type II collagen and CFA was successfully constructed. The arthritis index scores of rats in the treatment groups were decreased compared with the model group. The results of Western blotting showed that genistein obviously attenuate the levels of VEGF and MMP-1, 2 and 9 in serum (P<0.05). Immunohistochemical method showed that MVDs in the treatment groups were reduced as compared with the model group. CONCLUSION: The expressions of VEGF and MMP-1, 2 and 9 are related to the synovial pannus formation in CIA rats. The anti-angiogenic activity of genistein may correlate to its inhibitory effect on the expressions of VEGF and MMP-1, 2 and 9 in serum of CIA rats; genistein plus MTX are superior to single agents in treating rheumatoid arthritis.