Microbial cultures optimize rhizosphere bacterial community in Phyllostachys edulis forests

This study examined the impact of endophytic bacterial cultures, isolated from Phyllostachys edulis, on the bacterial communities within the P. edulis rhizome roots and rhizosphere, as well as on soil chemical properties. The mixed microbial cultures consisting of four strains was applied to experimental plots (low-yield forests). Seven rhizome roots samples were collected from P. edulis shoots at 0, 3, and 6 months: both treated and untreated samples were included at each time point. Similarly, seven rhizosphere soil samples were taken from P. edulis shoots at the same intervals, with treated and untreated samples at each time point. These samples were analyzed to assess changes in the rhizome roots endophytic and rhizosphere bacterial communities, as well as shifts in soil nutrient availability and chemical properties. The results indicated that after rarefaction to 93,259 sequences per sample, OTU-based (97% similarity) and Hellinger-transformed analyses revealed that treated samples showed increased bacterial richness (145-229) and Firmicutes abundance (1.9-11.1%) over six months, with directional shifts in community composition toward high-yield reference characteristics. However, Shannon diversity declined moderately (4.24 → 3.65) and remained below reference levels (p < 0.05). RDA identified EC, AP, TP, TK, AK, and AN as significant drivers (r² = 0.408-0.679, p < 0.05). The diversity of endophytic bacteria in P. edulis rhizome roots increased with the duration of microbial cultures application. The relative abundance of Firmicutes was notably influenced by the treatment. These findings demonstrate that microbial cultures positively influence the bacterial communities in both the rhizome roots and rhizosphere soil of P. edulis. Manipulating the bacterial community in P. edulis forest soils through the application of carefully selected beneficial strains appears to be a viable strategy.