The possibility of employing antagonistic bacteria for the control of tobacco brown spot was studied. Approximately 136 strains of bacteria were isolated from phyllospheres of tobacco and 9 of these possessed high lev...The possibility of employing antagonistic bacteria for the control of tobacco brown spot was studied. Approximately 136 strains of bacteria were isolated from phyllospheres of tobacco and 9 of these possessed high levels of antagonistic properties, They significantly reduced brown spot in detached tobacco leaves when artificially inoculated with Alternaria alternata. Culture filtrate of the most effective bacterial isolate which designated as Tpb88 was shown to be very efficient in inhibiting mycelial growth of A alternata in dual cultures. Culture filtrate of Tpb88 inhibited germination and germ tube elongation of A alternata. The results showed that the culture filtrate directly inhibited spore germination of A alternata, especially during the first hours of the paired cultivation. The rate of antagonistic activity of culture filtrate of Tpb88 depended on its concentration in the mixture. The greatest inhibition of spore germination was ob served at the highest concentration of filtrate （filtrate to fungal spores inocula mixed in proportion 1 ： 50）. These suggest that the hypothetic mechanism of Tpb88 against tobacco brown spot is to produce antagonistic substances.展开更多
采用平板分离法从桑树枝条中分离获得一株产α-葡萄糖苷酶抑制剂的内生真菌SZ-2,对该菌株进行鉴定和α-葡萄糖苷酶抑制活性检测。根据SZ-2菌株的形态特征、培养特征和5.8S r DNA/ITS序列分析,将其鉴定为链格孢菌(Alternaria sp.)。采用...采用平板分离法从桑树枝条中分离获得一株产α-葡萄糖苷酶抑制剂的内生真菌SZ-2,对该菌株进行鉴定和α-葡萄糖苷酶抑制活性检测。根据SZ-2菌株的形态特征、培养特征和5.8S r DNA/ITS序列分析,将其鉴定为链格孢菌(Alternaria sp.)。采用水提醇沉法提取发酵培养SZ-2菌株的菌丝多糖,测定菌丝多糖对α-葡萄糖苷酶具有较明显的体外抑制活性,IC_(50)值为6.98 mg/m L,且抑制类型属于典型的竞争性抑制作用。初步认为有望利用该菌株开发出新型的α-葡萄糖苷酶抑制剂。展开更多
基金State Tobacco Monopoly Administration of China (110200201008)
文摘The possibility of employing antagonistic bacteria for the control of tobacco brown spot was studied. Approximately 136 strains of bacteria were isolated from phyllospheres of tobacco and 9 of these possessed high levels of antagonistic properties, They significantly reduced brown spot in detached tobacco leaves when artificially inoculated with Alternaria alternata. Culture filtrate of the most effective bacterial isolate which designated as Tpb88 was shown to be very efficient in inhibiting mycelial growth of A alternata in dual cultures. Culture filtrate of Tpb88 inhibited germination and germ tube elongation of A alternata. The results showed that the culture filtrate directly inhibited spore germination of A alternata, especially during the first hours of the paired cultivation. The rate of antagonistic activity of culture filtrate of Tpb88 depended on its concentration in the mixture. The greatest inhibition of spore germination was ob served at the highest concentration of filtrate （filtrate to fungal spores inocula mixed in proportion 1 ： 50）. These suggest that the hypothetic mechanism of Tpb88 against tobacco brown spot is to produce antagonistic substances.
