Seasonal Diversity of Endophytic Bacteria Associated with Cinnamomum camphora (L.) Presl.

Abstract

Investigations on the density, diversity, and distribution of endophytic bacterial community associated with leaves of Cinnamomum camphora (L.) Presl. were carried out during three seasons using 16s rDNA high-throughput sequencing technology. Samples were collected from five species in Nanping (A, B, C, D, and E) and one from Fuqin (F) in the Fujian province, China in the months of April, July, and October (represented by 1, 2 and 3), indicating spring, summer, and early winter, respectively. Results from 16s rDNA sequences revealed 10,844,124 effective sequences. The highest OTUs (Operational taxonomic units) was highest in the A1 sample (1086), while the lowest was in C2 (509). Our observations showed that samples taken in October had the highest diversity of endophytes as indicated by the Shannon index (B3 = 5.3337), Chao1 (E3 = 1233.10), abundance-based coverage estimator (ACE) (A3 = 1764.72), and the Simpson indices of diversity (C3 = 0.1655) irrespective of the species. The order of the endophytes richness in the samples was April > July > October. The Ribosomal Database Project (RDP) classifier showed that the obtained sequences belonged to nine major phyla: Proteobacteria, Firmicutes, Bacteroidetes, Actinobacteria, Gemmatimonadetes, Acidobacteria, Planctomycetes, Chloroflexi, and Fusobacteria. Proteobacteria accounted for the highest proportion in each sample, ranging from 35.15% to 89.72%. These sequences belonged mainly to 10 orders: Rhizobiales, Clostridiales, Peseudomonadales, Burkholderiales, Bacteroidales, Enterobacteriales, Rhodocyclales, Sphingomonadales, Lactobacillales, and Bacillales. Also, other taxa with possible taxonomic statuses, which were unclassified, were present.