Main Article Content


Plant growth-promoting rhizobacteria (PGPR) contribute to an increase in crop yield through an environmentally friendly method, therefore eight rhizospheric bacteria, two of each genera Bacillus, Pseudomonas, Azotobacter and Azospirillum were examined for their efficacy to solubilize mineral nutrients using atomic absorption spectrophotometry and a flame photometer. Their potency to produce phytohormones, synthesis biocontrol components and their compatibility with pesticides using in vitro assays was studied. All of the chosen bacterial isolates proved positive for the above-mentioned Plant Growth Promoting traits. Among the eight bacterial isolates Pseudomonas isolate P69 showed the highest phosphorous solubilization efficiency of 190.91 % and another isolate P48 produced a maximum of 27.63µg mL-1 of gibberellic acid, Bacillus isolate B120 could solubilize maximum amount of ZnO and ZnCO3 accounting for 21.3ppm and 25.9ppm, respectively, not merely in terms of solubilization when compared to the other isolates, B120 produced the highest levels of HCN (77.33 ppm TCC) and siderophores (48.87psu). On day 9 after inoculation, Azotobacter isolate AZB17 performed effectively in potassium solubilization of 6.25g mL-1 with a pH drop to 3.83. The Azospirillum isolate ASP25 outperformed all other isolates in terms of IAA production (22.64g mL-1) and Bacillus isolate B365 was found to be more compatible with eight different pesticides used in the field at varying concentrations. All of these factors point to the possibility of using these bacterial isolates B120, P48, P69, AZB17, and ASP25 as biofertilizers in sustainable agriculture.


Atomic absorption spectrophotometry Flame photometer Pesticides Rhizobacteria Phytohormones

Article Details

How to Cite
Sanam, T., Triveni , S. ., Satyanaryana , J. ., Goud Nerella , S. ., Damodara Chari , K. ., & Desai , S. . (2021). Evaluation of diverse range microbes for their plant growth promoting abilities and their pesticide compatibility. Environment Conservation Journal, 22(3), 47–58.


  1. Kumar, A., Shukla, U. K., Singh, A., Poonam, A. K., Prasad, S., Singh, S. K., & Kumar, D. (2014). Evaluation of Pseudomonas isolates from wheat for some important plant growth promoting traits. African Journal of Microbiology Research, 8(27), 2604-2608. DOI:
  2. Ahmad, F., Ahmad, I., & Khan, M. S. (2008). Screening of free-living rhizospheric bacteria for their multiple plant growth promoting activities. Microbiological research, 163(2), 173-181. DOI:
  3. Bhattacharyya, P. N., & Jha, D. K. (2012). Plant growth-promoting rhizobacteria (PGPR): emergence in agriculture. World Journal of Microbiology and Biotechnology, 28(4), 1327-1350. DOI:
  4. Beneduzi, A., Ambrosini, A., & Passaglia, L. M. (2012). Plant growth-promoting rhizobacteria (PGPR): their potential as antagonists and biocontrol agents. Genetics and molecular biology, 35, 1044-1051. DOI:
  5. Borrow, A., Brian, P. W., Chester, V. E., Curtis, P. J., Hemming, H. G., Henehan, C., ... & Radley, M. (1955). Gibberellic acid, a metabolic product of the fungus Gibberella fujikuroi: some observations on its production and isolation. Journal of the Science of Food and Agriculture, 6(6), 340-348. DOI:
  6. Bric, J. M., Bostock, R. M., & Silverstone, S. E. (1991). Rapid in situ assay for indoleacetic acid production by bacteria immobilized on a nitrocellulose membrane. Applied and environmental Microbiology, 57(2), 535-538. DOI:
  7. Castric, K. F., & Castric, P. A. (1983). Method for rapid detection of cyanogenic bacteria. Applied and Environmental Microbiology, 45(2), 701-702. DOI:
  8. Chang, H. B., Lin, C. W., & Huang, H. J. (2005). Zinc-induced cell death in rice (Oryza sativa L.) roots. Plant growth regulation, 46(3), 261-266. DOI:
  9. Cho, S. T., Chang, H. H., Egamberdieva, D., Kamilova, F., Lugtenberg, B., & Kuo, C. H. (2015). Genome analysis of Pseudomonas fluorescens PCL1751: a rhizobacterium that controls root diseases and alleviates salt stress for its plant host. PLoS One, 10(10), e0140231. DOI:
  10. Das, K., Prasanna, R., & Saxena, A. K. (2017). Rhizobia: a potential biocontrol agent for soilborne fungal pathogens. Folia microbiologica, 62(5), 425-435. DOI:
  11. Deka, H., Deka, S., & Baruah, C. K. (2015). Plant growth promoting rhizobacteria for value addition: mechanism of action. In Plant-Growth-Promoting Rhizobacteria (PGPR) and Medicinal Plants (pp. 305-321). Springer, Cham. DOI:
  12. Dobereiner, J., Marriel, I. E., & Nery, M. (1976). Ecological distribution of Spirillum lipoferum Beijerinck. Canadian Journal of Microbiology, 22(10), 1464-1473. DOI:
  13. Dodd, I. C., Zinovkina, N. Y., Safronova, V. I., & Belimov, A. A. (2010). Rhizobacterial mediation of plant hormone status. Annals of Applied Biology, 157(3), 361-379. DOI:
  14. Fasim, F., Ahmed, N., Parsons, R., & Gadd, G. M. (2002). Solubilization of zinc salts by a bacterium isolated from the air environment of a tannery. FEMS microbiology letters, 213(1), 1-6. DOI:
  15. Gou, J., Ma, C., Kadmiel, M., Gai, Y., Strauss, S., Jiang, X., & Busov, V. (2011). Tissue?specific expression of Populus C19 GA 2?oxidases differentially regulate above?and below?ground biomass growth through control of bioactive GA concentrations. New Phytologist, 192(3), 626-639. DOI:
  16. Hayat, R., Ali, S., Amara, U., Khalid, R., & Ahmed, I. (2010). Soil beneficial bacteria and their role in plant growth promotion: a review. Annals of microbiology, 60(4), 579-598. DOI:
  17. Hinsinger, P., Betencourt, E., Bernard, L., Brauman, A., Plassard, C., Shen, J., ... & Zhang, F. (2011). P for two, sharing a scarce resource: soil phosphorus acquisition in the rhizosphere of intercropped species. Plant physiology, 156(3), 1078-1086. DOI:
  18. Janzen, R. A., Rood, S. B., Dormaar, J. F., & McGill, W. B. (1992). Azospirillum brasilense produces gibberellin in pure culture on chemically-defined medium and in co-culture on straw. Soil Biology and Biochemistry, 24(10), 1061-1064. DOI:
  19. Jensen, H. L. (1940). Nitrogen fixation and cellulose decomposition by soil microorganisms. I. Aerobic cellulose-decomposers in association with azotobacter. In Proceedings of the Linnean Society of New South Wales (Vol. 65, pp. 543-556).
  20. Jorquera, M. A., Hernández, M. T., Rengel, Z., Marschner, P., & de la Luz Mora, M. (2008). Isolation of culturable phosphobacteria with both phytate-mineralization and phosphate-solubilization activity from the rhizosphere of plants grown in a volcanic soil. Biology and Fertility of Soils, 44(8), 1025-1034. DOI:
  21. Kamilova, F., Okon, Y., de Weert, S., & Hora, K. (2015). Commercialization of microbes: manufacturing, inoculation, best practice for objective field testing, and registration. In Principles of plant-microbe interactions (pp. 319-327). Springer, Cham. DOI:
  22. Kapoor, R., Soni, R., & Kaur, M. (2016). Gibberellins production by fluorescent Pseudomonas isolated from Rhizospheric soil of Malus and Pyrus. International journal of agriculture, environment and biotechnology, 9(2), 193-199. DOI:
  23. King, E. O., Ward, M. K., & Raney, D. E. (1954). Two simple media for the demonstration of pyocyanin and fluorescin. The Journal of laboratory and clinical medicine, 44(2), 301-307.
  24. Knowles, C. J., & Bunch, A. W. (1986). Microbial cyanide metabolism. Advances in microbial physiology, 27, 73-111. DOI:
  25. Kumar, G. P., Desai, S., Amalraj, L., & Reddy, G. (2015). Isolation of fluorescent Pseudomonas spp. from diverse agro-ecosystems of India and characterization of their PGPR traits. Bacteriology Journal, 5(1), 13-24. DOI:
  26. Kundu, B. S., & Gaur, A. C. (1984). Rice response to inoculation with N 2-fixing and P-solubilizing microorganisms. Plant and Soil, 79(2), 227-234. DOI:
  27. Loper, J. E., & Schroth, M. N. (1986). Influence of bacterial sources of indole-3-acetic acid on root elongation of sugar beet. Phytopathology, 76(4), 386-389. DOI:
  28. Mhlongo, M. I., Piater, L. A., Madala, N. E., Labuschagne, N., & Dubery, I. A. (2018). The chemistry of plant–microbe interactions in the rhizosphere and the potential for metabolomics to reveal signaling related to defense priming and induced systemic resistance. Frontiers in Plant Science, 9, 112. DOI:
  29. Mukherjee, P., Roychowdhury, R., & Roy, M. (2017). Phytoremediation potential of rhizobacterial isolates from Kans grass (Saccharum spontaneum) of fly ash ponds. Clean Technologies and Environmental Policy, 19(5), 1373-1385. DOI:
  30. Mustafa, A., Naveed, M., Saeed, Q., Ashraf, M. N., Hussain, A., Abbas, T., ... & Minggang, X. (2019). Application potentials of plant growth promoting rhizobacteria and fungi as an alternative to conventional weed control methods. Sustainable Crop Production. DOI:
  31. Naqqash, T., Hameed, S., Imran, A., Hanif, M. K., Majeed, A., & van Elsas, J. D. (2016). Differential response of potato toward inoculation with taxonomically diverse plant growth promoting rhizobacteria. Frontiers in plant science, 7, 144. DOI:
  32. Nirmal Kumar, J. I., Bora, A., & Amb, M. K. (2010). Chronic toxicity of the triazole fungicide tebuconazole on a heterocystous, nitrogen-fixing rice paddy field cyanobacterium, Westiellopsis prolifica Janet. Journal of microbiology and biotechnology, 20(7), 1134-1139. DOI:
  33. Payne, S. M. (1993). Iron acquisition in microbial pathogenesis. Trends in microbiology, 1(2), 66-69. DOI:
  34. Reeves, M. W., Pine, L., Neilands, J. B., & Balows, A. (1983). Absence of siderophore activity in Legionella species grown in iron-deficient media. Journal of Bacteriology, 154(1), 324-329. DOI:
  35. Sarwar, S., Khaliq, A., Yousra, M., Sultan, T., Ahmad, N., & Khan, M. Z. (2020). Screening of Siderophore-Producing PGPRs Isolated from Groundnut (Arachis hypogaea L.) Rhizosphere and Their Influence on Iron Release in Soil. Communications in Soil Science and Plant Analysis, 51(12), 1680-1692. DOI:
  36. Schwyn, B., & Neilands, J. B. (1987). Universal chemical assay for the detection and determination of siderophores. Analytical biochemistry, 160(1), 47-56. DOI:
  37. Siddiqui, I. A., Shaukat, S. S., Sheikh, I. H., & Khan, A. (2006). Role of cyanide production by Pseudomonas fluorescens CHA0 in the suppression of root-knot nematode, Meloidogyne javanica in tomato. World Journal of Microbiology and Biotechnology, 22(6), 641-650. DOI:
  38. Somers, E., Vanderleyden, J., & Srinivasan, M. (2004). Rhizosphere bacterial signalling: a love parade beneath our feet. Critical reviews in microbiology, 30(4), 205-240. DOI:
  39. Stefan, M., Munteanu, N., Stoleru, V., Mihasan, M. and Hritcu, L., 2013. Seed inoculation with plant growth promoting rhizobacteria enhances photosynthesis and yield of runner bean (Phaseolus coccineus L.). Scientia Horticulturae, 151: 22–29. DOI:
  40. Suja, G., John, K. S., Sreekumar, J., & Srinivas, T. (2010). Short?duration cassava genotypes for crop diversification in the humid tropics: growth dynamics, biomass, yield and quality. Journal of the Science of Food and Agriculture, 90(2), 188-198. DOI:
  41. Trolldenier, G. (1987). Curl, EA and B. Truelove: The Rhizosphere.(Advanced Series in Agricultural Sciences, Vol. 15) Springer?Verlag, Berlin?Heidelberg?New York?Tokyo, 1986. 288 p, 57 figs., Hardcover DM 228.00, ISBN 3–540–15803–0. DOI:
  42. Verma, P., Yadav, A. N., Khannam, K. S., Saxena, A. K., & Suman, A. (2017). Potassium-solubilizing microbes: diversity, distribution, and role in plant growth promotion. In Microorganisms for green revolution (pp. 125-149). Springer, Singapore. DOI:
  43. Vyas, P., & Gulati, A. (2009). Organic acid production in vitro and plant growth promotion in maize under controlled environment by phosphate-solubilizing fluorescent Pseudomonas. BMC microbiology, 9(1), 1-15. DOI:
  44. Zachow, C., Müller, H., Monk, J., & Berg, G. (2017). Complete genome sequence of Pseudomonas brassicacearum strain L13-6-12, a biological control agent from the rhizosphere of potato. Standards in genomic sciences, 12(1), 1-7. DOI:
  45. Zhang, X., Zhang, R., Gao, J., Wang, X., Fan, F., Ma, X., ... & Deng, Y. (2017). Thirty-one years of rice-rice-green manure rotations shape the rhizosphere microbial community and enrich beneficial bacteria. Soil Biology and Biochemistry, 104, 208-217. DOI: