Core microflora and endophytic interaction network of Oxytropis glacialis in Qinghai-Tibet Plateau

Abstract:

[Background] Endophyte is beneficial to host plants for survival and diffusion, and the interaction network of flora provides a basic guarantee for the realization of ecological functions of endophyte. [Objective] To understand the main endophytic microbiota and their interaction network of Oxytropis glacialis that affects the development of animal husbandry in Tibet, so as to provide a reference for the scientific management and utilization of the poisonous plants of locoweed on the Qinghai-Tibet Plateau. [Methods] High-throughput sequencing was used to analyze the endophytic microbiota in the ecotone, to construct the endophytic microbiota correlation network, and to analyze the interaction model of ecotone with the endophytic microbiota related to the metabolism of swainsonine. [Results] A total of 175 791 valid sequences of endophytic bacteria were obtained by sequencing, which annotated to 428 bacterial OTU, belonging to 19 phyla and 267 genera. A total of 757 113 valid sequences of endophytic fungi were obtained, which annotated to 391 fungal OTU, belonging to 7 phylum and 149 genera, Venn diagram analysis showed that the number of endophytic bacteria genus in the core of root and leaf tissues (54, 62) was greater than that of the core endophytic fungi (22, 13), and the core endophytic bacteria species in root tissues were similar to that in leaf tissues (76, 75). Phylogenetic tree analysis showed that Alternaria and Brevundimonas, presenting in Oxytropis glacialis were endophyte that produced and degraded swainsonine. Network analysis showed that the correlation between endogenous bacteria flora was given priority to positive feedback interaction network relationship, the core flora may mainly through indirect interaction modes to affect the microbial community, including Alternaria and Brevundimonas as core species with indirect significant correlation (|r|>0.6, P<0.01) in bacteria interactions within networks. [Conclusion] Oxytropis glacialis core microbiota indirectly participates in the interaction network among endophytes, and the high degree of bacterial connectivity makes it possible to realize the function of endophytes.

Key words:Endophyte, Locoweed, Swainsonine, High-throughput sequencing (HTS), Microbial interaction