Lin Youjian, He Zhenli, Rosskopf Erin N, Conn Kenneth L, Powell Charles A, Lazarovits George
Indian River Research and Education Center, University of Florida, Fort Pierce 34945 and Plant Protection College, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China.
Indian River Research and Education Center, University of Florida.
Plant Dis. 2010 Feb;94(2):201-206. doi: 10.1094/PDIS-94-2-0201.
A new nylon membrane bag (NMB) assay was developed for studies to determine the effect of chemicals added to soil on survival of soilborne plant pathogens. The rapid and effective assay can be used to study organisms for which there are no selective media or for which a selective medium is expensive or difficult to prepare. This assay consists of placing pathogens inside a bag made of small-pore (0.22-μm) nylon filtration membrane, which is placed in soil and later retrieved to determine survival of the pathogens on nonselective media. Chemicals but not other microorganisms can enter the bag from the soil. Using this assay, Streptomyces scabies, Fusarium oxysporum f. sp. lycopersici race 3, and Ralstonia solanacearum were successfully recovered from soil after 72 h as demonstrated by growth on a semiselective Streptomyces medium (S. scabies) or nonselective potato dextrose agar medium (F. oxysporum f. sp. lycopersici race 3 and R. solanacearum) with minimal microbial contamination. Addition of acetic acid (200 mM) to soil killed 100% of S. scabies. SPK (a mixture of organic chemicals) at a concentration of 1,500 mg kg of soil killed 83.3% of F. oxysporum f. sp. lycopersici race 3 culture plugs, 100% of F. oxysporum f. sp. lycopersici race 3 spores, and 97.2% of R. solanacearum cells. SPK at 1,000 mg kg of soil killed 50% of F. oxysporum f. sp. lycopersici race 3 culture plugs, 68.2% of F. oxysporum f. sp. lycopersici race 3 spores, and 12% of R. solanacearum. Benlate (500 to 1,500 mg kg of soil) did not kill the culture plugs of F. oxysporum f. sp. lycopersici race 3 but reduced the growth rate of F. oxysporum f. sp. lycopersici race 3. Benlate (500, 1,000, and 1,500 mg kg of soil) reduced F. oxysporum f. sp. lycopersici race 3 spore germination by 39.4, 49.3, and 50.4%, respectively. Streptomycin sulfate (1,500, 800, 400, and 200 mg kg of soil) caused 75.3, 21, 11.9, and 0.9% mortality, respectively, of R. solanacearum.
开发了一种新的尼龙膜袋（NMB）测定法，用于研究添加到土壤中的化学物质对土传植物病原体存活的影响。这种快速有效的测定法可用于研究那些没有选择性培养基，或者选择性培养基昂贵或难以制备的生物体。该测定法包括将病原体置于由小孔径（0.22μm）尼龙过滤膜制成的袋子中，将袋子放置在土壤中，之后取回以确定病原体在非选择性培养基上的存活情况。化学物质而非其他微生物可以从土壤进入袋子。使用这种测定法，72小时后从土壤中成功回收了疮痂链霉菌、尖孢镰刀菌番茄专化型3号生理小种和青枯雷尔氏菌，通过在半选择性链霉菌培养基（用于疮痂链霉菌）或非选择性马铃薯葡萄糖琼脂培养基（用于尖孢镰刀菌番茄专化型3号生理小种和青枯雷尔氏菌）上生长，且微生物污染最小来证明这一点。向土壤中添加乙酸（200 mM）可杀死100% 的疮痂链霉菌。浓度为1500 mg/kg土壤的SPK（一种有机化学物质混合物）可杀死83.3% 的尖孢镰刀菌番茄专化型3号生理小种培养菌块、100% 的尖孢镰刀菌番茄专化型3号生理小种孢子和97.2% 的青枯雷尔氏菌细胞。浓度为1000 mg/kg土壤的SPK可杀死50% 的尖孢镰刀菌番茄专化型3号生理小种培养菌块、68.2% 的尖孢镰刀菌番茄专化型3号生理小种孢子和12% 的青枯雷尔氏菌。苯菌灵（500至1500 mg/kg土壤）不会杀死尖孢镰刀菌番茄专化型3号生理小种的培养菌块，但会降低尖孢镰刀菌番茄专化型3号生理小种的生长速率。苯菌灵（500、1000和1500 mg/kg土壤）分别使尖孢镰刀菌番茄专化型3号生理小种孢子萌发率降低39.4%、49.3% 和50.4%。硫酸链霉素（1500、800、400和200 mg/kg土壤）分别导致青枯雷尔氏菌死亡率为75.3%、21%、11.9% 和0.9%。
