一株来源于土壤的耐盐酵母菌鉴定及其与植物互作研究

目的]鉴定一株来源于土壤的耐盐酵母菌并探讨其与植物的互作关系。方法]对分离自恩施市龙洞河附近的马尾松根部土壤的一株真菌YSTEn005进行鉴定,并研究盐胁迫下其与植物的互作关系。结果]条件生长试验表明,YSTEn005对Na Cl的最高耐受水平可达10%,而对高浓度的K+不敏感。YSTEn005最适生长温度为28℃,在含4%盐的液体培养基中生长最快;其对p H耐受范围较宽,可在p H 4.0~9.0条件下生长。显微镜下观察YSTEn005是单细胞形态,菌体呈椭球型,并能够行类似酵母的出芽生殖。克隆其18S r DNA,序列分析表明该真菌与高耐盐酵母——汉逊德巴利酵母(Debaryomyces hansenii)的亲缘关系最近,推测YSTEn005很可能是汉逊德巴利酵母的一株变异种。该菌和拟南芥幼苗共培养显示,YSTEn005的增殖可显著降低植株在盐胁迫下的存活率。结论]试验得到一株耐盐酵母菌YSTEn005,该菌不能改善植物对盐分的耐受性能。

Identification of A Strain of Salt-tolerance Halophilic Yeast from Soil and Its Interaction with Plant

Objective] The aim was to identify a strain of salt-tolerance halophilic yeast from soil and study its interaction with plant.Method] A halophilic yeast YSTEn005 was isolated from the Pinus massoniana rhizosphere soil in Enshi,and it interaction with plant was explored under salt stress.Result] YSTEn005 could grow on the medium supplemented with up to 10% NaCl,and it appeared in sensitive to K+;the optimum growth temperature of YSTEn005 was 28 ℃,and growth rate was higher in medium with 4% NaCl than other series of degrees;YSTEn005 was tolerant to wide pH relatively,which ranged from 4.0 to 9.0.YSTEn005 was single cell pattern under microscope,and displayed budding similar to that of yeast.Cloning its 18S rDNA and analysis the sequence indicated that the YSTEn005 was evolutionally close to Debaryomyces hansenii,which is a halophilic yeast,suggesting that YSTEn005 was from this genus.When co-cultured with plants,YSTEn005 growth promoted Arabidopsis seedlings dying significantly under salt stress conditions.Conclusion] A strain of halophilic yeast YSTEn005 is obtained from soil,and the YSTEn005 growth is not helpful to plants tolerant to salt stress.