Effect of the dark septate endophytic fungus Acrocalymma vagum on heavy metal content in tobacco leaves

Dark septate endophytic fungi are symbiotes that play an important role in plant resistance to biotic and abiotic stress. In this study, 65 strains of endophytic fungi were obtained from tobacco roots using a tissue isolation method. Strains NYN8C05 and NYN8G01 were identified as Acrocalymma vagum based on ITS rDNA sequence analysis and morphological characteristics. Co-culture experiments showed that strains NYN8C05 and NYN8G01 can promote the growth of tobacco seedlings. Observations of roots after trypan blue staining showed that strains NYN8C05 and NYN8G01 colonized the roots and formed dark septate hyphae and microsclerotia. These results confirmed that strains NYN8C05 and NYN8G01 were dark septate endophytic fungi. Pot experiments showed that NYN8C05 and NYN8G01 significantly decreased the heavy metal content in leaves of tobacco plants. A. vagum strains NYN8C05 and NYN8G01 are dark septate endophytic fungi that have application potential for decreasing heavy metal content in tobacco leaves.