Molecular Phylogenetics of Microbial Endophytes Endowed with Plant Growth-promoting Traits from Populus tomentosa

ENDOPHYTIC microorganisms are used as substitutes for chemical fertilizers and pesticides for increasing plant growth and productivity. In this study, we isolated 90 bacterial and 64 endophytic fungal isolates from the roots, stems, and leaves of different genotypes of Chinese white poplar (Populus tomentosa Carr.). The isolated endophytes were screened for the production of plant growth-promoting parameters, such as indole-3-acetic acid, siderophores, and inorganic phosphate solubilization. Furthermore, the endophytes were assessed for their activities of hydrolytic enzymes, such as amylase, cellulase, and pectinase. In vitro tests were conducted to visualize root colonization for the most potent isolates. Furthermore, 16S rRNA sequence analysis indicated that strains 24RB, 33RB, 59SB, 85LB, and 88LB displayed similarities to Enterobacter tabaci, Bacillus velezensis, Bacillus megaterium, Pantoea eucrina, and Bacillus aryabhattai ; these strains are deposited in GenBank under accession numbers MN540932.1, MN559965.1, MN540915.1, MN541091.1, and MN540958.1, respectively. Based on nucleotide sequencing from the internal transcribed spacer of rDNA, fungal isolate codes 17RF, 37RF, 46SF, 48SF, 52SF, and 63LF were identified as Lasiosphaeriaceae sp., Chaetomium globosum, Aspergillus niger, Peyronellaea sp., Talaromyces amestolkiae, and Alternaria sp. and deposited in GenBank with accession numbers MN541090.1, MN541117.1, MN540962.1, MN540968.1, MN540956.1, and MN541096.1, respectively. In conclusion, these strains have the potential to be commercialized for agricultural purposes.