Rhizosphere microbiome of Hopea celebica in Karst Forest

BACKGROUND AND OBJECTIVES: Hopea celebica is an endangered dipterocarp endemic to Sulawesi, restricted to fragile karst forests with shallow nutrient poor soils. Despite its high conservation value and increasing habitat threats, ecological knowledge, particularly of its belowground microbial associations, remains limited. The rhizosphere microbiome plays an important role in plant nutrition and stress tolerance, yet the microbial community associated with H. celebica has not been documented. This objective of this study were to document bacterial diversity and identify ecologically and functionally important dominant taxa in the rhizosphere of H. celebica in the Maros-Pangkep Karst region.METHODS: Rhizosphere soil samples were collected from four natural populations of Hopea celebica within the Maros Karst region, South Sulawesi, Indonesia. Total community deoxyribonucleic acid was extracted, and bacterial community composition was assessed using 16S ribosomal ribonucleic acid gene amplicon sequencing targeting the Variable regions 3 and 4 region on the deoxyribonucleic acid nanoball sequencing-G400 platform. Sequence data were processed using the quantitative Insights Into microbial ecology 2 pipeline, including quality filtering, amplicon sequence variant inference, and taxonomic classification against the systematic interactive labeled viewer of alignments 138.1 reference database. Alpha diversity indices were applied to evaluate bacterial richness and evenness among sampling sites.