Lecanicillium saksenae (Kushwaha) Kurihara and Sukarno, a versatile endophytic entomopathogenic fungus for plant growth promotion in rice (Oryza sativa L.).

Beyond pest suppression, entomopathogenic fungi are recently recognized for their ability to colonize plants endophytically, enhancing resilience against various biotic and abiotic stresses. The present study aimed to investigate the potential of an indigenous entomopathogenic fungus, Lecanicillium saksenae, isolated from the soils of Kerala, India, not only as an endophyte but also as a plant growth promoter in rice. In vitro assays revealed its ability to synthesize phytohormones, solubilize phosphorus and zinc, and produce ammonia and siderophores. Following seed inoculation, L. saksenae persisted up to 90 days after inoculation, as confirmed by re-isolation. PCR and SEM observations confirmed its systemic colonization in plant parts. Growth and yield attributes of inoculated plants were analysed using Student’s t-test (P < 0.05). There was a significant increase in germination (6.38%), seedling vigour (51.46%), shoot and root lengths (30.30% and 55.58%), and leaf and root counts (35.29% and 26.58%) at the seedling stage. At the later growth stages, plant height (25.80%), number of tillers (36.90%), number of panicles (30.00%), number of filled grains (24.20%), grain yield (30.00%), and straw yield (28.40%) were enhanced significantly compared to the control. LC-MS analysis detected elevated levels of auxins, gibberellins, and cytokinins at the seedling and tillering stages. At the maximum tillering stage, spectrophotometric analysis revealed elevated levels of total sugars, proteins, and phenols, while GC-MS revealed carbohydrate predominance in inoculated plants. Notably, this is the first report confirming the endophytism of the entomopathogen L. saksenae in rice, demonstrating its potential for sustainable rice cultivation.