Taxonomic and Functional Diversity of Leaves and Stem Endophytes of Eight Agave Species

More than 63% of Mexico’s territory is classified as arid or semiarid, where plants belonging to the genus Agave have evolved. Adaptation to drylands resulted from biochemical, physiological, and anatomical properties shared with other crassulacean plants; however, microbial symbionts also play critical roles in plants’ growth, health, and drought tolerance. To explore endophytic communities in Agave plants, we used a shotgun metagenomic approach. The taxonomic and functional diversity of endophytes were studied in the leaves and stem organs of Agave americana, A.angustifolia, A. fourcroydes, A. karwinskii, A. potatorum, A. tequilana, A. cupreata, and A. rodacantha. The microbial community structure did not differ significantly among species, regardless of geographic origin or local environmental conditions, whereas significant differences were observed between organs. We found 4058 genera shared among organs, of which 957 genera are exclusive to the stem and 492 to the leaves. The community analysis of stems and leaves identified bacterial genera, including Acinetobacter, Klebsiella, Escherichia, Corynebacterium, and Streptomyces. Significant differences were also observed between organs in the functional annotations. The dominant functional categories were associated with cell signaling and protein metabolism in both organs.