A first characterization of the leaflet endophytic prokaryotic community in Dioon cycads

Abstract

Studies describing prokaryotic communities in cycad species have a long history. To date, interest in understanding the microbial community in cycad species continues, with a main focus on the coralloid root endosphere and rhizosphere microbiomes. In particular, studies have emphasized the predominant biotic interaction with cyanobacteria. However, the variation of the leaf endosphere microbiome composition among wild cycad species has not been extensively studied. In this study, we employed 16S rRNA amplicon analysis in six Dioon species to provide insight into the leaf endosphere microbial composition in cycads and its interspecific variation. We focused on the diversity of the microbiome among three Dioon species pairs: D. vovidesii–D. sonorense, D. caputoi–D. califanoi, and D. oaxacensis–D. merolae. Their prokaryotic alpha and beta diversities were also estimated. Although our report is based on a limited number of samples, we observed that, overall, gram-negative Delftia and Pseudomonas were abundant in most samples, except in the pair D. caputoi–D. califanoi. Also, the prokaryotic community in D. vovidesii (the northernmost species) was the most distinct among the six evaluated species. Within each species pair, species from xeric environments showed higher levels of microbiome diversity, suggesting the hypothesis that adaptation to aridity is favored by high microbiome diversity.