Functional characterisation of endophytic bacteria of Drynaria quercifolia L.(J.)Sm: production of hydrolytic enzymes and plant growth-promotion

Isolation, Molecular Identification and Plant Growth-Promoting Potential of Rhizome-Associated Endophytic Bacteria from Curcuma caesia Roxb.

Curcuma caesia Roxb. (black turmeric) is an important medicinal plant belonging to the family Zingiberaceae and is valued for its diverse therapeutic properties. In addition to its rich phytochemical composition, the plant harbours diverse endophytic microorganisms that colonise internal tissues without causing disease symptoms. Among these, bacterial endophytes contribute significantly to plant growth promotion, nutrient mobilisation, stress tolerance, biological control, and the production of bioactive compounds. However, limited information is available on the cultivable bacterial endophytes associated with C. caesia and their functional potential. Therefore, the present study aimed to isolate, molecularly identify, and evaluate the plant growth-promoting potential of rhizome-associated bacterial endophytes from C. caesia. Healthy rhizomes were surface-sterilised to eliminate epiphytic microorganisms and subjected to aseptic isolation procedures using nutrient agar medium. Three morphologically distinct bacterial isolates were obtained, purified, and characterised on the basis of their cultural and morphological features. Genomic DNA was extracted from the purified isolates, and molecular identification was performed through amplification and sequencing of the 16S rRNA gene, followed by comparative analysis using the NCBI GenBank database. The isolates were identified as Enterobacter hormaechei, Bacillus flexus, and Bacillus amyloliquefaciens, with high sequence similarity to their respective reference strains. The identified isolates were further evaluated for plant growth-promoting traits, including indole-3-acetic acid (IAA) production, phosphate solubilisation, ammonia production, and hydrogen cyanide (HCN) production. All isolates exhibited the assessed plant growth-promoting characteristics, indicating their potential as beneficial microbial resources. The findings demonstrate that C. caesia harbours diverse cultivable bacterial endophytes of ecological and biotechnological importance. These endophytic bacteria may serve as potential candidates for the development of microbial inoculants, sustainable agricultural practices, extracellular enzyme production, and bioactive metabolite exploration. The present study provides baseline information on the bacterial endophytic diversity of C. caesia and highlights its potential applications in agricultural biotechnology and plant–microbe interaction studies.

Klebsiella sp. IR6, an endophytic rhizobacteria with potential as a plant growth-promoting agent for Jalapeño pepper (Capsicum annum L.) production.

IR6 exhibited the most notable agronomic performance, increasing seedling leaf area, fruit production, and fruit size under field conditions and demonstrating antagonistic activity against Fusarium oxysporum, confirming its potential as a biocontrol agent and PGPR.

Functional Characterization of Wheat Seed Endophytic Bacteria Reveals Plant Growth-Promoting Traits and Potential Biocontrol Activity Against Fusarium Pathogens.

A functionally diverse seed endophytic community with complementary roles in plant growth and disease suppression is revealed and rational selection and combination of complementary strains, particularly N. cucumis WSSR17 (growth promotion), C. erzurumensis WSSR11 (biocontrol), and P. poae WSSR12 (multifunctional nutrient mobilization) could enable the development of targeted, multi-strain bioinoculant strategies for wheat.

Integrative functional profiling of rhizospheric and endophytic bacteria reveals Lelliottia aquatilis as a multifunctional PGPR in Himalayan ecosystems

This study introduces L. aquatilis strain MC3 as an emerging candidate for bioinoculant development and one of the first reports for identification of L. aquatilis as multifunctional PGPR from Himalayan ecosystems.

Plant growth promotion of rice (Oryza sativa L.) with root endophytic bacteria, isolated from wild Solanaceous medicinal plants Solanum nigrum L., Solanum sisymbriifolium Lam., and Solanum virginianum L.

Functional characterization of a plant growth-promoting endophytic fungus associated with Vanda tessellata

Endophytic fungi play an important role in promoting plant growth by producing phytohormones and enhancing nutrient availability; however, their functional roles in orchids remain poorly understood. This study aimed to isolate and functionally characterize plant growth-promoting (PGP) endophytic fungi associated with Vanda tessellata (Roxb.) Hook. ex G.Don. Six representative endophytic fungal isolates were evaluated for plant growth-promoting traits, among which isolate KU/BOT/VT004 exhibited the highest activity. Based on morphological characteristics and ITS rDNA sequence analysis, the isolate was identified as Colletotrichum cf. cobbittiense. The isolate produced high levels of indole-3-acetic acid (35.05 µg/mL), along with ammonia and siderophore activity, indicating strong nutrient-mobilizing potential. Application of the fungal culture filtrate to in vitro-grown protocorms resulted in a two- to three-fold increase in biomass and significantly enhanced chlorophyll content compared with untreated controls. Filtrate-treated protocorms also maintained sustained growth beyond 60 days, whereas nutrient-limited control protocorms exhibited reduced growth. These findings demonstrate the growth-promoting potential of metabolites produced by isolate KU/BOT/VT004 and suggest that this endophytic fungus is a promising candidate for future bioinoculant development and orchid propagation, pending further validation through fungal inoculation and colonization studies.