烟草赤星病菌嘧菌酯敏感与抗性菌株的代谢表型差异分析

 为了解烟草赤星病菌(Alternaria alternata)嘧菌酯抗性菌株与敏感菌株在代谢表型上的差异,采用Biolog代谢表型技术比较了抗性菌株(6-5和6-11)和敏感菌株(J6)的950种代谢表型。结果表明,抗性菌株和敏感菌株在代谢表型上基本一致,2个抗性菌株均不能代谢糖酵解中的氮源D-甘露糖胺,抗性菌株6-11还不能代谢尿素循环中的氮源L-鸟氨酸。烟草赤星病菌能代谢24.74%、85.26%、97.14%、89.83%的供试碳、氮、硫、磷源;具有广泛渗透压和pH适应能力;具有脱羧酶活性而无脱氨酶活性;能在高达10%氯化钠、6%氯化钾、5%硫酸钠、20%乙二醇、6%甲酸钠、6%尿素、12%乳酸钠、200 mmol·L^-1 磷酸钠、100 mmol·L^-1硫酸铵、100 mmol·L^-1硝酸钠和20 mmol·L^-1亚硝酸钠的渗透液中正常代谢,不能在20~200 mmol·L^-1的苯甲酸钠渗透液中代谢;其pH适应范围为3.5~10.0,最适约为6.0。研究结果有助于了解烟草赤星病菌的营养需求特性、渗透压和pH环境适应力,同时从代谢表型上揭示了赤星病菌对嘧菌酯抗性的潜在机理。

Difference analysis between azoxystrobin-sensitive and -resistant isolates of Alternaria alternata causing tobacco brown spot in metabolic phenotypic characterization

In order to assess the metabolic phenotype difference of azoxystrobin-sensitive and -resistant isolates of Alternaria alternata, the pathogen of tobacco brown spot, 950 metabolic phenotypes of both resistant isolates (6-5 and 6-11) and sensitive isolate (J6) were compared using Biolog phenotype microassay technology. Results showed that the metabolic fingerprints of the two resistant isolates were nearly the same as that of the sensitive isolate J6. However, the two resistant isolates could not metabolize nitrogen substrate D-mannosamine that metabolized in glycolysis, while isolate 6-11 could not metabolize nitrogen substrate L-ornithine that metabolized in urea cycle. A. alternata was able to metabolize 24.74%, 85.26%, 97.14% and 89.83% of the tested carbon, nitrogen, sulfur and phosphorus sources, respectively. It showed decarboxylase activity, while no deaminase activity. It could metabolize in various hyperosmolytic solutions, including up to 10% sodium chloride, 6% potassium chloride, 5% sodium sulfate, 20% ethylene glycol, 6% sodium formate, 6% urea, 12% sodium lactate, 200 mmol·L^-1 sodium phosphate, 100 mmol·L^-1 ammonium sulfate, 100 mmol·L^-1 sodium nitrate or 20 mmol·L^-1 sodium nitrite, but not metabolize in 20-200 mmol·L^-1 sodium benzoate osmolytic solution. It was able to grow in pH 3.5 to 10.0, with optimal pH around 6.0. These findings help to know the nutritional requirements of A. alternata, and its adaptabilities to different osmolytes and pH environments, and help to understand the potential resistance mechanism of A. alternata to azoxystrobin.