ISSN: 0973-7510

E-ISSN: 2581-690X

Research Article | Open Access
T.K. Radha1,2 , D.L.N. Rao1, K.R. Sreeramulu3, P.U. Krishnaraj4 and T.K. Roopa5
1AINP on Soil Biodiversity-Biofertilizers, Indian Institute of Soil Science, Bhopal, Madhya Pradesh, India.
2Division of Natural Resources, Indian Institute of Horticulture Research, Bengaluru, Karnataka, India.
3Department of Agricultural Microbiology, University of Agricultural Sciences, GKVK, Bengaluru, Karnataka, India.
4Department of Agricultural Biotechnology, University of Agricultural Sciences, Dharwad, Karnataka, India.
5Department of Livestock Farm Complex, KVAFSU, Veterinary College, Karnataka, India.
Article Number: 10005 | © The Author(s). 2025
J Pure Appl Microbiol. 2025;19(2):1528-1540. https://doi.org/10.22207/JPAM.19.2.58
Received: 22 October 2024 | Accepted: 06 February 2025 | Published online: 04 June 2025
Issue online: June 2025
Abstract

Actinobacteria are mainly involved in decomposition of organic materials, promotion of plant growth, nutrient mineralization and antagonism against plant pathogens. In the present study forty one Actinobacterial isolates obtained from the different agro ecological (arid, semi arid and humid) regions of India were characterized. Thirty-five out of the 41 isolates produced indole acetic acid (IAA) and 16 isolates produced gibberellic acid (GA) in vitro; Thirty isolates were able to solubilize tri-calcium phosphate (TCP) and 15 were able to solubilize potassium from muscovite mica. Thirty-two isolates showed alkaline phosphatase activity. Glass house screening identified 9 isolates that were highly effective in promoting plant dry weight (>35%) when inoculated on maize and on chickpea (>30%). The principal component analysis showed that isolate A6 was found to be effective in increasing the plant growth parameters both in 30 and 45 DAS, followed by A1 in Maize and A10 was effective at 30 DAS and A17 in 60 DAS on Chick pea. Molecular confirmation using 16S rRNA gene sequence of the strain showed that A1 had 98% similarity with S. enissocaesilis (NCBI Accession no.: MF070481) A6 had only 84% similarity with S. djakartensis which may be a novel organism in terms of activity and A10 had 98% similarity with S. mutabilis (Accession no.: MF070483). A16 had 97% similarity with S. enissocaesilis (Accession no.: MH591469) and A25 had 97% similarity with S. rochei, (Accession no.: MH633722) A28 had 98% similarity with S. rochei (Accession no.: MH633727) and A36 had 97% similarity with Acinetobacter johnsonii (Accession no.: MH636837). The identified strains from our study have a good potential for use as bioinoculants for dryland crops to obtain enhanced crop growth and yield.

Keywords

Actinobacteria, PGPR, Arid, Semi-arid, Maize, Chickpea

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