Endophytic bacteria that promote the plant growth and development have been isolated from rice apoplastic fluid. The rice leaf apoplast is an intracellular compartment that exists outside the plasma membrane and contains the plant's cell wall. Nutrient transport, cell signalling, water absorption, export, and plant endophytic interactions are all the significant functions of the apoplast. Endophytic bacteria have the capacity to improve the plant development and nutrient acquisition by fixing atmospheric nitrogen, solubilizing phosphorus, potassium, zinc, and producing phytohormones such as IAA, gibberellic acid, and siderophore in subsistent quantities. Nine distinct endophytic bacterial isolates were isolated from varied selected locations, and examined based on morphological and biochemical methods. Among the nine isolates, RAF-2 is a distinct endophytic bacteria has been characterized at molecular level sequencing and identified as Leclercia adecarboxylata (OM169350), and the pioneering work reported on rice. It has been found as the significant phytohormone producer includes IAA (29.77 µg 25 mL-1), GA3 (6.02 µg 25 mL-1), and has an excellent ACC deaminase activity (19.33 µmol α-Kβ mg-1 protein-1 h-1) respectively. RAF-2 (Leclercia adecarboxylata) (OM169350) isolated from rice apoplastic fluid was performed as the best in producing phytohormones such as IAA, GA3, and has an excellent ACC deaminase activity, and this could be recommended as an effective phytohormone producer for the sustainable production of crops.

Apoplastic fluid, Endophytic bacteria, Plant growth promoting endophytes, Leclercia adecarboxylata, ACC deaminase activity

Plant growth promoting endophytic bacterial isolates viz., Azospirillium, Bacillus, Pseudomonas, Leclercia, Paenibacillus, Methylobacterium were isolated from rice leaves and examined through Morphological and biochemical characterizing methods. in vitro plant growth promoting activity were assessed for its efficiency to produce IAA, GA3, and analysis of ACC deaminase activity, From the following studies, it could be concluded that among the different bacterial endophytes, RAF-2 (Leclercia adecarboxylata) (OM169350) isolated from rice apoplastic fluid was performed as the best in producing phytohormones such as IAA, GA3, and has an excellent ACC deaminase activity, and this could be recommended as an effective phytohormone producer for the sustainable production of crops.

Nismal Aswin A. and K. Sharan (2022). Leclercia adecarboxylata - A Putative PGP Phytohormone Producing Endophytic Bacterial Isolate Molecular characterization of Leclercia adecarboxylata. Biological Forum – An International Journal, 14(4a): 410-417.