Biological functions of endophytic bacteria in Robinia pseudoacacia ‘Hongsen’

Abstract

IntroductionEndophytes and their host plants have co-evolved for a very long time. This relationship has led to the general recognition of endophytes as a particular class of microbial resources.R. pseudoacacia‘Hongsen’ is drought- and barren-resistant species that can be grown in both the north and south of China, efficiently addresses the ecological issues caused by China’s ‘southern eucalyptus and northern poplar. Up to date, cultured-dependent studies are available for theR. pseudoacacianitrogen-fixing and other endophytes. Therefore, the present research studied theR. pseudoacacia‘Hongsen,’ microbiome in detail by high-throughput sequencing and culture dependant.MethodsThis study examined microbial species and functional diversity inRobinia pseudoacacia‘Hongsen’ using culture-dependent (isolation) and culture-independent techniques.ResultsA total of 210 isolates were isolated fromR. pseudoacacia‘Hongsen.’ These isolates were clustered into 16 groups by the In Situ PCR (IS-PCR) fingerprinting patterns. 16S rRNA gene sequence analysis of the representative strain of each group revealed that these groups belonged to 16 species of 8 genera, demonstrating the diversity of endophytes inR. pseudoacacia‘Hongsen’. ’Bacillusis the most prevalent genus among all the endophytic bacteria. High-throughput sequencing of endophytic bacteria fromR. pseudoacacia‘Hongsen’ of the plant and the rhizosphere soil bacteria showed that the bacterial populations of soil near the root, leaf, and rhizosphere differed significantly. The microbial abundance decreased in the endophytes as compared to the rhizosphere. We observed a similar community structure of roots and leaves. With and without root nodules,Mesorhizobiumsp. was significantly different inR. pseudoacacia‘Hongsen’ plant.DiscussionIt was predicted thatR. pseudoacacia‘Hongsen’ plant endophytic bacteria would play a significant role in the metabolic process, such as carbohydrate metabolism, amino acid metabolism, membrane transport, and energy metabolism.