Endophytic Bacterial Community Diversity in Pulp of Different Litchi Varieties Based on High-throughput Sequencing Analysis

Abstract

【Objective】Endophytic bacteria exert an important role in plant growth and development. The study aims to analyze the community structure and diversity of endophytic bacteria in pulp of different litchi varieties, and screen and utilize the potential endophytic bacteria resources, which would provide references for further research on the interaction between litchi and endophytic bacteria.【Method】The pulp tissues of 6 different litchi varieties were used as materials. MiSeq high-throughput sequencing technology was used to compare and analyze the community composition and dominant flora of endophytic bacteria at phylum, family, genus and species classification levels in pulp tissues after the V3~V4 region of 16S rDNA was amplified by PCR. The diversity of endophytic bacteria was evaluated combined with Alpha diversity analysis.【Result】A total of 2 139 086 sequences of endophytic bacteria 16S rDNA were obtained in the V3~V4 region of 6 litchi varieties, and the average length of amplified sequences was 376 bp. There was no significant difference in the abundance and diversity of endophytic bacteria in different litchi varieties. At the phylum classification level, Proteobacteria was the main dominant bacterial group in litchi pulp tissue, followed by Actinomyces. At the levels of family, genus and species classification, the endophytic bacterial community structure of different litchi varieties was similar, but the bacterial abundance proportion was different. Differential bacterial community analysis showed that the Pseudomonas, Pectobacterium, Ochrobactrum and Dickeya were significantly enriched in the high-quality varieties of 'Edanli', 'Nuomici' and 'Guanyinlv'. In addition, Bradyrhizobium and Snodgrassella were only enriched in the 'Edanli'. The clustering analysis of relative abundance of bacteria showed that 'Guanyinlv', 'Nuomici' and 'Edanli', had higher similarity. Alpha diversity analysis showed that there were differences in the abundance and diversity of endophytic flora in pulps of 6 litchi varieties, but the differences were not significant.【Conclusion】In this study, the community structure of endophytic bacteria in the pulp of six different litchi varieties was analyzed, and some unique microbial genera were enriched in the high-quality litchi varieties. The results could provide a theoretical basis and important references for the development and utilization of endophytic bacteria to improve litchi quality.

Keywords

• litchi pulp
• endophytic bacteria, community structure
• microbial diversity
• dominant bacterial community
• high-throughput sequencing