桉树内生真菌二型伞霉的培养条件优化

Optimized Culture Conditions of the Endophytic Fungus Umbelopsis dimorpha from Eucalyptus Roots

明确桉树内生真菌二型伞霉的最适培养条件,为桉树内生真菌共生机制研究以及内生真菌的实际生产应用奠定基础。采用固体培养和液体培养,研究不同温度(20、25、30、35℃)、pH值(4.0、5.0、6.0、7.0、8.0)、碳源(葡萄糖、蔗糖、麦芽糖、甘露醇、果糖、乳糖和山梨醇)、氮源(磷酸氢二铵、草酸铵、硫酸铵、氯化铵、尿素、胰蛋白胨和蛋白胨)、转速(80、100、120 r/min和140 r/min)对二型伞霉生长的影响。同时回接巨桉,测量其株高与根长,探究接种二型伞霉对巨桉的影响。结果表明,二型伞霉在不同碳源和不同氮源的MMN培养基均能生长,但生长速度和生物量存在显著差异,最佳碳源为乳糖,其次是葡萄糖,最佳氮源为蛋白胨,其次是尿素。二型伞霉适宜生长温度为30℃,生长最快、长势最好,适宜生长pH为6.0~7.0,最佳转速为80 r/min。接种二型伞霉2个月后巨桉株高和根长分别比对照显著提高48.22%和75.78%。初步确定了桉树内生真菌二型伞霉的最佳培养条件,验证了其对桉树生长的促进作用,为桉树内生真菌的生理生化研究和资源的开发利用提供理论依据。

The objective of this research was to find the optimal culture conditions of Umbelopsis dimorpha,and to lay a foundation for the study on the endosymbiosis mechanism of Eucalyptus fungi and the actual production and application of endophytic fungi.Endophytic fungi from Eucalyptus roots were cultured in solid medium and liquid medium.Then,we investigated the effects of different carbon sources(glucose,sucrose,maltose,mannitol,fructose,lactose and sorbitol),nitrogen sources((NH 4)2HPO 4,(NH 4)2SO 4,NH 4Cl,ammonium oxalate,urea,tryptone and peptone),temperatures(15,20,25,30,and 35℃),pH(4.0,5.0,6.0,7.0,and 8.0)and rotational speed(80,100,120,and 140 r/min)on fungi growth.We measured the shoot and root lengths of Eucalyptus to explore the effect of the inoculation of U.dimorpha on Eucalyptus grandis at the same time.U.dimorpha could grow in MMN medium with different carbon and nitrogen sources,however,the growth rate and biomass of U.dimorpha were significantly different.The best carbon source was lactose,and sub.optimum carbon source was glucose,the best nitrogen source was peptone,followed by urea.U.dimorpha grew and performed well when the temperature was 30℃.The optimum pH for the growth of U.dimorpha was 6.0-7.0.The optimal rotational speed was 80 r/min.The shoot and root length of Eucalyptus increased significantly by 48.22%and 75.78%,respectively,after inoculating U.dimorpha for two months.We preliminarily determined the optimal culturing requirements of U.dimorpha under control conditions,and also confirmed the promotion effect of U.dimorpha on the growth of Eucalyptus,which would provide a theoretical basis for the physiological and biochemical researches of endophytic fungi in Eucalyptus and the development and utilization of endophytic fungi resources.