Effect of interaction between AMF Glomus bagyarajii and PGPR Methylobacterium radiotolerans on tomato seedlings raised in Pro Trays
Authors:   Department of Microbiology, St Joseph’s College (Autonomous), # 36, Lalbagh Road, Bengaluru - 560027 Email:ashwin.bengaluru@gmail.com, M.C RANJITHA , R. ASHWIN , D.J. BAGYARAJ 
Published: December 2024

Abstract
The present study evaluated the effect of dual inoculation with Glomus bagyarajii (AMF) and Methylobacterium radiotolerans (PGPR) on the growth and quality of tomato seedlings raised in pro trays under polyhouse conditions. Compared to uninoculated seedlings, those treated with the microbial consortium exhibited significantly enhanced shoot and root length, stem diameter, and seedling dry weight. Dual inoculation resulted in a 25 and 21 percent increase in shoot and root length, respectively, and a 49% improvement in the biovolume index (BI), which reflects seedling quality. Root colonization by AMF reached 100 per cent in dual-inoculated plants, compared to 90 per cent in AMF-only treatments, indicating superior compatibility and synergistic interaction between the fungus and bacteria. Additionally, dual inoculation significantly increased rhizosphere microbial populations, highlighting its role in promoting beneficial microbial activity. These results underline the potential of G. bagyarajii and M. radiotolerans as a microbial consortium for raising healthy, vigorous tomato seedlings.
References
Abhaya, D., Nikhil, N., Ashwin, R. and Bagyaraj, D.J., 2019. Influence of arbuscular mycorrhizal fungus (Funneliformis mosseae) and plant growth promoting rhizobacteria (PGPR) on growth of tomato seedlings raised in protrays. J. Soil Biol. Ecol., 39: 53-63.
Anuroopa, N., Bagyaraj, D.J., Bagela A. and Prakash Rao E.V.S., 2017. Inoculation with selected microbial consortia not only enhances growth and yield of Withania somnifera but also reduces fertilizer application by 25% under field conditions. Proc. Indian Nat. Sci. Acad., 83: 957–971.
Ashwin, R., Bagyaraj, D. J. and Mohan Raju, B., 2023. Ameliorating the drought stress tolerance of a susceptible soybean cultivar, MAUS 2 through dual inoculation with selected rhizobia and AM fungus. Fungal Biol. Biotechnol., 10:10. https://doi.org/10.1186/s40694-023-00157-y
Bagyaraj, D.J., 2011. Microbial Biotechnology for Sustainable Agriculture, Horticulture & Forestry; New India Publishing Agency, New Delhi, India.
Bagyaraj, D.J. and Sturmer, S.L., 2008. Arbuscular Mycorrhizal Fungi. In: A handbook of Tropical Soil Biology: Sampling and Characterization of Belowground Biodiversity (Eds. Moreira, F.M.S., Huising, J.E., Bignell, D.E.), Earthscan Pub., London, UK, pp. 131–147.
Barea, J.M., Azcon, R. and Azcon-Aguilar, C., 2002. Mycorrhizosphere interactions to improve plant fitness and soil quality. Antonie Van Leeuwenhoek, 81: 343–51.
Ben-David, A. and Davidson, C.E., 2014. Estimation method for serial dilution experiments. J. Microbiol. Methods, 107: 214–221.
Bhattacharyya, A., Pablo, C.H., Mavrodi, O.V., Weller, D.M., Thomashow, L.S. and Mavrodi, D.V. 2021. Rhizosphere plant-microbe interactions under water stress. Adv. Appl. Microbiol., 115: 65–113.
Buttar, D.S., Singh, N. and Singh, N., 2016. Impact of phosphorus amendments on colonization and spore population of Glomus bagyarajii (AM fungi) in chickpea. Plant Disease Res., 31: 40–44.
Chauhan, H. and Bagyaraj, D.J., 2015. Inoculation with selected microbial consortia not only enhances growth and yield of French bean but also reduces fertilizer application under field condition. Sci. Hortic., 197: 441–446.
de Andrade, L.A., Santos, C.H., Frezarin, E.T., Sales, L.R. and Rigobelo, E.C., 2023. Plant growth-promoting rhizobacteria for sustainable agricultural production. Microorganisms. 11(4):1088.
Desai, S., Bagyaraj, D. J. and Ashwin, R., 2020. Inoculation with microbial consortium promotes growth of tomato and capsicum seedlings raised in pro trays. Proc. Nat. Acad. Sci. India Sec B Biol. Sci., 90: 21-28.
Fasusi, O.A., Babalola, O.O. and Adejumo, T.O., 2023. Harnessing of plant growth-promoting rhizobacteria and arbuscular mycorrhizal fungi in agroecosystem sustainability. CABI Agric. Biosci., 4(1):26.
Giovannetti, M. and Mosse, B., 1980. An evaluation of techniques to measure vesicular arbuscular infection in roots. New Phytol. 84: 489–500.
Gracy, L.S. and Bagyaraj, D.J., 2006. Influence of Glomus bagyarajii and PGPRs on the growth, nutrition and forskolin concentration of Coleus forskohlii. Biol. Agric. Hort., 23: 371–381.
Grossi, C.E., Fantino, E., Serral, F., Zawoznik, M.S., Fernandez Do Porto, D.A. and Ulloa, R.M., 2020. Methylobacterium sp. 2A is a plant growth-promoting rhizobacteria that has the potential to improve potato crop yield under adverse conditions. Front. Plant Sci., 11:71.
Hatchell, G.E., Berry, C.R. and Muse, H.D. 1985. Nondestructive indices related to aboveground biomass of young loblolly and sand pines on ectomycorrhizal and fertilizer plots. For. Sci. 31: 419–427.
Henkes, G.J., Kandeler, E., Marhan, S., Scheu, S. and Bonkowski, M., 2018. Interactions of mycorrhiza and protists in the rhizosphere systemically alter microbial community composition, plant shoot-to-root ratio and within-root system nitrogen allocation. Front. Environ. Sci. 6:117.
Jenifer Sheeba, J., Ranadev, P., Ashwin, R. and Bagyaraj, D.J., 2022. Influence of AM fungus Funneliformis mosseae and K solubilizing bacterium Bacillus mucilaginosus on the growth of tomato seedlings raised in pro trays. J. Microbes Res. 1(2): 1-6.
Kumar, R.R. and Jadeja, V.J., 2016. Isolation of actinomycetes: A complete approach. Int. J. Curr. Microbiol. App. Sci., 5(5): 606-618.
Madhaiyan, M., Alex, T.H., Ngoh, S.T. and Prithiviraj, B., Ji, L., 2015. Leaf-residing Methylobacterium species fix nitrogen and promote biomass and seed production in Jatropha curcas. Biotechnol. Biofuels, 8:1-4.
Maskina, M.S., Meelu, O.P. and Roberts, D.L., 1984. Effect of organic and inorganic manuring on rice nurseries. Int. Rice Res. Newsl., 9: 265–275.
Navdeep, S., Daljeet, S. and Narinder, S., 2017. Effect of Glomus bagyarajii inoculation and phosphorus amendments on Fusarial wilt of chickpea. Agric. Res. J. 54: 236–243.
Pan J., Huang C., Peng F., Zhang W., Luo J., Ma S. and Xue, X., 2020. Effect of arbuscular mycorrhizal fungi (AMF) and plant growth-promoting bacteria (PGPR) inoculations on Elaeagnus angustifolia L. in saline soil. Appl. Sci., 10: 945.
Philips, J.M. and Hayman, D.S., 1970. Improved procedures for clearing roots and staining parasitic and vesicular-arbuscular mycorrhizal fungi for rapid assessment of infection. Trans. Br. Mycol. Soc., 55: 158–161.
Praveen, R., Ashwin, R., Joanna, D. and Bagyaraj, D.J., 2023. Arbuscular mycorrhizal fungi as biofertilizers for sustainable agriculture. In: Biofertilizers: Agricultural Uses, Management and Environmental Effects (Ed. Bevis, P.L.), Nova Science Publishers, NY, USA. pp. 1-31.
Praveen, R., Anuroopa, N., Ashwin, R. and Bagyaraj, D.J., 2022. Symbiotic response of fodder cowpea (Vigna unguiculata L.) and field bean (Lablab purpureus L.) with different arbuscular mycorrhizal fungi. Kavaka, 58: 34–38.
Raghavendra Kumar, M., Ashwin, R. and Bagyaraj, D.J., 2018. Screening arbuscular mycorrhizal fungi in order to select the best for alleviating wilt disease complex of capsicum. Proc. Natl. Acad. Sci. Sec. B Biol. Sci., 88: 679–684.
Shakunthala, N., Nikhil, N., Ashwin, R. and Bagyaraj, D.J., 2019. Role of arbuscular mycorrhizal fungus (Funneliformis mosseae) on growth of tomato seedlings raised in protrays. J. Soil. Biol. Ecol., 39: 32-38.
Smith, G.S., Johnston, C.M. and Cornforth, I.S., 1983. Comparison of nutrient solutions for growth of plants in sand culture. New Phytol., 94: 537–548.
Sukeerthi, D., Nikhil, N., Ashwin, R. and Bagyaraj, D.J., 2020. Microbial consortium promotes growth of zinnia and balsam seedlings raised in pro trays. J. Floric. Landscap. 6: 04-08
Thilagar G., Bagyaraj D.J. and Rao M.S., 2016. Selected microbial consortia developed for chilly reduces application of chemical fertilizers by 50% under field conditions. Sci. Hortic. 198: 27–35.
Wahab, A., Muhammad, M., Munir, A., Abdi, G., Zaman, W., Ayaz, A., Khizar, C. and Reddy, S.P.P., 2023. Role of arbuscular mycorrhizal fungi in regulating growth, enhancing productivity, and potentially influencing ecosystems under abiotic and biotic stresses. Plants, 12:3102.
Yamuna, J, Bagyaraj, D. J. and Ashwin, R., 2018. Response of field bean to inoculation with PGPR Bacillus sonorensis and AM fungus Funneliformis mosseae. J Soil Biol. Ecol. 38: 104-111.
Zhang C, Wang MY, Khan N, Tan LL and Yang S., 2021. Potentials, utilization, and bioengineering of plant growth-promoting Methylobacterium for sustainable agriculture. Sustainability, 13:3941.