Investigating the growth-promoting effects of entophytic fungi isolated from Camellia luteflora on tomato seedlings

<i>Camellia luteflora</i>, an endangered plant species native to China, faces significant conservation challenges due to its limited habitat and vulnerability to pathogens. Investigating the entophytic fungal communities within <i>C. luteflora</i>, particularly those that promote plant growth and stress resilience, is crucial. Through systematic evaluation, the growth-promoting ability of entophytic fungi from <i>C. luteflora</i> and the effects of inoculation on the growth of tomato seedlings were investigated. Among the 35 isolated entophytic fungi, 7 strains exhibited the ability to synthesize indole-3-acetic acid (IAA), 24 strains showed nitrogen-fixing abilities, 27 strains were capable of producing protease, and 15 entophytic strains had a siderophore utilization (SU) value exceeding 10.00%. Furthermore, five strains were identified as capable of potassium solubilization, and seven strains as phosphorus solubilizers. Three strains demonstrated a dual ability for phosphorus and potassium solubilization. The entophytic fungal inocula derived from entophytic fungi CG-II-1, CJ-V-1, and DJ-I-4 resulted in significant enhancement of chlorophyll content in tomato seedlings, as well as promoting root development and biomass accumulation. This study found that CJ-V-1 (<i>Colletotrichum siamense</i>) and CG-II-1 (<i>Helotiales</i> sp.) have significant potential for promoting plant growth, creating opportunities for utilizing these strains as innovative resources for entophytic fungal inocula development.