2022 Vol.28 No.2 PP 177-190

https://doi.org/10.33451/florafauna.v28i2pp177-190

Isolation and bioactivity screening of Streptomyces spp. associated with Curcuma caesia (Yaimu) from Manipur, India

Khullakpam Shaheen, *Debananda S. Ningthoujam, Saikat Mukherjee and Shantirani Thokchom

Microbial Biotechnology Research Laboratory,
Department of Biochemistry,
Manipur University, CANCHIPUR (MANIPUR), INDIA
*Corresponding Author : E-mail: debananda.ningthoujam@gmail.com

ABSTRACT

Thirty four (34) endophytic bacteria were isolated from Curcuma caesia, locally known as Yaimu. The putative endophytic isolates were subjected to antibacterial screening against four (4) bacterial test organisms and antifungal assays against six (6) indicator rice fungal pathogens. The isolates were further screened for plant growth promoting (PGP) traits such as IAA, siderophore, ammonia production and phosphate solubilisation. Four (4) isolates (MBRL 750, MBRL 752, MBRL 755 and MBRL 757) were positive in all the PGP traits. MBRL 755, the most potent PGP strain and another promising strain MBRL 750 produced significant amounts of IAA (138 ìg/mL, 76 ìg/mL respectively) and ammonia (27.4 μg/ml, 23.2 ìg/mL respectively) as well as efficiently solubilised phosphate (50 μg/ml, 22 ìg/mL respectively). These bioactive isolates were subjected to rice seedling vigor assays (Variety: Jatra). The best isolate, MBRL 750, showed higher vigor index (199.8) over the control (181.5). The shortlisted bioactive strains (MBRL 755, MBRL 750) were characterised by 16S rDNA sequencing and designated as Streptomyces sp. MBRL 755 and Streptomyces sp. MBRL 750. The bioactive strains MBRL 755 and MBRL 750 hold promise for development as bioinoculants for rice cultivation.

KEY WORDS : Antimicrobial assays, Curcuma caesia, Endophytic bacteria, Isolates, Seed vigor index, streptomyces spp.