Isolation and Categorization of Plant Growth Promoting Endophytic Bacteria Isolated from Halophytic Suaeda nigra at Salt Stress Area of Srikakulam, Andhra Pradesh

Abstract

In search of novel endophytic bacteria capable of producing plant growth promoting phytohormones and providing tolerance against biotic and abiotic stress to the plant, present study was carried out during 2021-22. For this, endophytic bacteria were isolated from halophytic Suaeda nigra at salt stress areas of Srikakulam district, Andhra Pradesh. Total of sixteen endophytic bacteria were isolated from roots and aerial parts of Suaeda nigra. Isolates were enumerated, purified and preserved for subsequent studies. All isolates were analyzed for their phenotypic, biochemical, enzymatic assay and molecular characterization was carried out by 16S rRNA molecular method. Isolates were tested for their ability in producing plant growth promoting phytohormones, siderophores, exo enzymes and ability to solubilize the phosphate molecules. Among total isolates extracted, bacteria which was labeled as “SNA7” isolated from aerial parts of Suaeda nigra showed better characters in producing catalytic enzymes like catalase, amylase, protease, phosphate solubilization ability and Indole-3-acetic acid (IAA) production. Isolate SNA7 was gram negative, motile, aerobic, rod shaped, non-spore forming, and no pigmentation which grows best at 42°C, pH 8.3 with tolerate of 8% NaCl nutrient agar. Based on phenotypic, biochemical, nucleotide homology and phylogenetic analysis isolate SNA7showed higher relationship with Pseudomonas pseudoalcaligenes Pseudomonas spp. was characterized as an effective organism to explore its ability in various research fields. In this current study, isolate SNA7 showed higher potential in producing wide range of enzymes and bioactive secondary metabolites and was first of its kind reported and isolated from halophytic Suaeda nigra.