铜尾矿库白羊草内生真菌的分布及rDNA-ITS系统发育

Distribution and rDNA-ITS sequence analysis of endophyte symbionts of Bothriochloa ischaemum at a copper tailings site

对北方铜业铜矿峪矿十八河尾矿库的优势植被白羊草内生真菌染菌率进行调查,采集活体植株进行叶鞘内生真菌分离,并对白羊草内生真菌的形态特征及孢子形态进行描述,同时,选取其中16株进行5.8S-ITS扩增、测序和系统发育分析。结果表明,从生长在4个不同恢复年限子坝的白羊草中分离出形态不同的内生真菌,其中以白色菌落居多,生长速度位于5.515~12.548 mm/d之间。孢子形态以球型和椭圆型为主,大小介于2.085~7.072μm之间。分子鉴定结果显示16种内生真菌属于3个属,为赤霉属(Gibberella)、镰刀菌属(Fusarium)、青霉属(Penicillium),恢复30年与5年的子坝白羊草内生真菌遗传距离最小,亲缘关系最近,恢复45年与15年的子坝白羊草内生真菌亲缘关系最远。铜矿库不同恢复年限的土壤环境可能导致白羊草感染内生真菌的多样性,这为进一步丰富铜尾矿库内生真菌资源,揭示生活在铜尾矿的白羊草内生真菌的生态功能提供理论依据。

Tailing ponds are special growth environment for plants.Soils at such sites contain high concentrations of heavy metals,which affect the physiology and ecology of plants.The aim of this study was to evaluate the endophytic fungi resources at a copper mine tailings site,and to explore whether different endophytic fungi can restore diversity by altering the physical and chemical properties of soil.Therefore,we studied endophytic fungi of Bothriochloa ischaemum growing in the Shibahe tailings pools at the Tongkuangyu Mine,a copper tailings site.B.ischaemumis the dominant species growing at this site,and it grows in several sub-dams with different recovery times.To investigate the endophytic fungi infection rate of B.ischaemum,we collected live plants and separated the endophyte from the sheath,and observed and described the characteristics and spore morphology of each fungus.We also selected 16 strains and amplified the 5.8S-ITS region for sequencing and phylogenetic analysis.Based on their phenotypes,the endophytes fromB.ischaemumgrowing in four different sub-dams with different recovery times were separated into different groups.Most endophyte colonies were white,and the growth rate ranged from 5.515 and 12.548mm/d.The endophytes produced spherical or oval/near oval spores,with sizes ranging from 2.085μm to 7.072μm.Sequence analyses showed that there were three different sequences among the 16 kinds of colonies,belonging to the genera Gibberella,Fusarium,and Penicillium.The smallest genetic distance was between the sub-dam with 30-years recovery and that with 5-years recovery.The largest genetic distance was between the sub-dam with 45-years recovery and that with 15-years recovery.At copper tailings sites,different soil environments at different stages of restoration might lead to a wide diversity of endophytes infecting B.ischaemum.The results of this study provide a theoretical basis for enriching endophyte resources,and reveal some of the ecological functions of endophytes associated with B.ischaemumat a copper tailings site.