继代培养对链格孢菌生长及产毒的影响

Influences of subculture on the growth and Alternaria toxins production of Alternaria alternata

中文关键词:  链格孢菌  继代培养  角变  产孢  链格孢霉毒素

英文关键词:Alternaria alternata  subculture  sectorization  conidial production  Alternaria toxins

中文摘要:

      目的 探究连续继代培养对链格孢菌(Alternaria alternata)菌株的生长以及产毒的影响。方法 将10株链格孢菌在马铃薯葡萄糖琼脂培养基(potato dextrose agar, PDA)上连续继代培养, 分析菌株的生长、产孢情况; 利用超高效液相色谱-串联质谱法(ultra performance liquid chromatography-tandem mass spectrometry, UPLC-MS/MS)检测并分析主要链格孢霉毒素[包括交链孢酚(alternariol, AOH)、交链孢酚单甲醚(alternariol monomethyl ether, AME)、交链孢烯(altenuene, ALT)、细交链格孢菌酮酸(tenuazonic acid, TeA)]的含量变化。结果 在PDA培养基中, 连续继代培养链格孢菌极易出现角变、菌丝变白、菌丝生长速率加快等菌株退化现象。随着继代培养次数的增加, 菌株生长速度加快, 菌落直径变大, 角变率增大; 10株链格孢菌中有7株(MY-4、MY-12、MY-15、MY-73、MY-80、MY-103、MY-117)产孢量随着继代次数的增加先增加后降低, 3株(MY-65、MY-67和MY-108)产孢量随着继代次数的增加显著降低; 10株链格孢菌中有4株可以产生TeA毒素, 且TeA毒素的含量随着继代次数的增加先上升后下降, 第五代菌株(F5)产毒能力最强。继代培养对ALT毒素含量影响较大, 除MY-103以外, 随着继代次数的增加, ALT毒素的含量显著降低(达91.13%~99.85%)。AOH和AME毒素含量随着继代次数的增加呈下降或者呈先上升后下降的趋势。结论 连续继代培养5代对链格孢菌的生长、产孢、产毒等均会产生较大影响。在菌株的实际应用过程中, 应该避免菌株过多次的继代培养, 尽量使用5代以内的链格孢菌。

英文摘要:

      Objective To investigate the influences of successive subculture on the growth and Alternaria toxins production of Alternaria alternata. Methods The changes of the fungi growth and conidiation of 10 strains of A. alternata were studied during successive subculture on potato dextrose agar (PDA) medium. The content of main Alternaria toxins, including alternariol (AOH), alternariol monomethyl ether (AME), altenuene (ALT), tenuazonic acid (TeA) were detected and analyzed by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Results The successive subculture of A. alternata on the PDA medium was prone to the degradation of the strain, such as sectorization, colony bleaching and over growth of the hyphae. With the increase of subculture times, the growth speed, the colony diameter, and the sectorization rate increased. The conidial productions of 7 strains (MY-4, MY-12, MY-15, MY-73, MY-80, MY-103, MY-117) increased first and then decreased, while the conidial productions of the other 3 strains (MY-65, MY-67 and MY-108) declined significantly along with the increased subculture times. Among the 10 strains, 4 strains could produce TeA, and the content of TeA first increased and then decreased with the increased subculture times, of which, the toxigenic ability of the fifth generation (F5) was the highest. Subculture could cause a great effect on the content of ALT, except for MY-103. Along with the increased subculture times, the content of ALT declined significantly (up to 91.13%?99.85%). The content of AOH and AME decreased or increased first and then decreased with the increase of subculture times. Conclusion Successive subculture for 5 generations can lead to great influences on the fungi growth, conidial production and Alternaria toxins production of A. alternata. In the practical application process of the strains, it should avoid the subculture of the strainsmore than once, and use A. alternata within 5 generations as much as possible.