The presented study investigated the diversity and phenetic relationships of endophytic bacterial communities isolated from three patchouli (Pogostemon cablin Benth.) cultivars found in Aceh, Indonesia, viz., Tapaktuan, Sidikalang, and Lhokseumawe. The obtained isolates totaled 77, coming from roots, stems, and leaves of the patchouli cultivars and entailing characterization based on morphological features. These include colony shape, margin, elevation, appearance, optical property, pigmentation, Gram reaction, and cell shape. The results demonstrated considerable morphological diversity across cultivars and plant organs, with Lhokseumawe exhibiting the highest diversity of isolates. Most isolates were Gram-positive, distributed mainly in the stem tissues. Cluster analysis using the unweighted pair group method with arithmetic mean (UPGMA) and the Numerical Taxonomy System (NTSYS)-pc software revealed no distinct grouping of isolates by plant cultivar and its parts. However, organ-specific tendencies were evident. Cluster I consisted mostly of root-derived isolates (15 out of 27 isolates, 55.6%) (non-pigmented Gram-positive cocci), whereas cluster II comprised predominantly of stem- and leaf-associated bacteria (brighter-pigmented Gram-positive bacilli and Gram-negative bacilli, respectively). Although morphology-based traits provided useful preliminary insights, their limitations underscored the need for molecular approaches for accurate characterization. Overall, these findings offer a valuable basis for harnessing native endophytes in sustainable patchouli cultivation and disease management.
Patchouli (P. cablin Benth.), cultivars, endophytic bacteria, isolates, cluster analysis, morphological features, microbial diversity, organ-specific tendencies
The 77 endophytic bacterial isolates obtained from three patchouli (P. cablin Benth.) cultivars were morphologically diverse and did not cluster strictly by plant cultivar and plant parts. However, organ-specific tendencies were notable. The findings highlighted the limitations of morphological traits for bacterial classification and suggested that organ-specific microenvironments influence the diversity of bacterial endophytes.