Document Type : Research Paper

Authors

1 Department of Soil Science, Faculty of Agriculture, Shahid Bahonar University of Kerman, Kerman, Iran.

2 Department of Soil Science, Faculty of Agriculture, Vali-e-asr University of Rafsanjan, Kerman, Iran.

Abstract

Introduction: Plants are usually exposed to a wide variety of abiotic stresses which can seriously inhibit plant growth and development. To address this, numerous strategies have been proposed and used by researchers, including increased irrigation rounds, cultivation of salinity- and drought-resistant genetically modified crops (GMO crops), and application of plant-growth-promoting rhizobacteria (PGPRs). PGPRs can act as an efficacious, long-lasting, and crucial option to ameliorate the negative impacts of abiotic stresses in crops. Plant growth promoting rhizobacteria can serve as key in sustainable agriculture by improving soil fertility, plant tolerance, crop productivity, and maintaining a balanced nutrient cycling. Consequently, search for new strains of PGPR for biofertilizer and development of microbial diversity map for any region is helpful. Hence, the present study investigates the effect of native salinity-resistant PGPRs on the physiological and biochemical characteristics and productivity of alfalfa plants in soil under salinity stress.
Materials and methods: The present study was based on a completely randomized factorial design. The experiments were conducted on alfalfa plants (Bami variety) in four repetitions and under two levels of salinity (control and 200 mM sodium chloride and calcium chloride) with five strains of PGPRs from Sinorhizobium meliloti sp., two positive controls (i.e., 20 mg/kg of phosphorus and 70 mg/kg of nitrogen fertilizers), two negative controls (i.e., no fertilizer and no bacteria), and two treatments (including positive control and negative control). Growth parameters (dry weight of aerial parts, roots, and nodules), osmolytes (reducing sugars, soluble proteins, and proline), uptake of K+ and K+/Na+ ratio, and concentration of malondialdehyde (MDA) in alfalfa plants in non-saline and saline soils were measured at the end of 60-day experiments.
Results and discussion: The analysis of variance (ANOVA) results revealed a significant effect of salinity on the dry weight of aerial parts and roots, the weight and number of nodes in each pot, the K+/Na+ ratio in roots and aerial parts, and the concentration of reducing sugars, proline, MDA, and soluble proteins in the aerial parts. The effect of PGPRs was also found to be significant on all the above traits. Under no salinity stress and compared to negative control plants, the dry weight of aerial parts in plants inoculated with superior PGPRs (SM89, SM16, and SM65) was raised by 2.3, 1.9, and 1.8 folds, while this increase in plants inoculated with mild (SM73) and weak (SM21) PGPRs was 1.4 and 1.2 folds, respectively. Under salinity stress (200 mM NaCl and CaCl2) and compared to negative control plants, the increase in dry weight of aerial parts of plants inoculated with superior PGPRs (SM89, SM16, and SM65) was increased by 4.2, 4, and 2.1 folds, while this increase in plants inoculated with mild (SM73) and weak (SM21) PGPRs was raised by 1.7 and 1.2 folds, respectively. Despite a drop in the growth of aerial parts in plants under salinity, salinity-resistant PGPRs were able to significantly enhance the growth of aerial parts of plants in saline conditions compared to the controls (receiving no fertilizer and PGPRs). Salinity stress reduced other growth parameters, the rate of K+ uptake, and the K+/Na+ ratio, while it contrarily increased the concentration of reducing sugars, soluble proteins, proline, Na+, and MDA in plants. Inoculation of alfalfa plants with two superior PGPRs (SM89 and SM16) was found to significantly improve growth parameters, uptake of K+, osmolytes, and K+/Na+ ratio in alfalfa plants under non-saline conditions and salt stress, compared to control plants (not inoculated with PGPRs and receiving no fertilizer). Ultimately, each inoculation of plants with all three superior PGPRs reduced the concentration of MDA and Na+ in alfalfa plants.
Conclusion: Experiments on the biochemical and physiological plant–PGPR interactions revealed that plant responses to stresses are largely controlled by microbial communication. PGPRs can trigger systemic resistance in plants through their metabolites, which function as extracellular signals, thereby enabling plants to survive under abiotic stresses. In the present study, microbial inoculation was found to significantly improve the physiological functioning of the plants. The results revealed that adding native salinity-resistant PGPRs to the soil can diminish the negative effects of salinity stress on alfalfa plants. Likewise, inoculation and enrichment of the plant's rhizosphere with beneficial and resistant microbiomes were efficient for sustaining the growth of plants under abiotic stresses such as salinity.

Keywords

Main Subjects

  1. Abolhasani Zeraaatkar, M., and Tajabadi Pour, A. 2023. Isolation, Screening and Identification of Growth-Promoting Rhizobacteria Resistant to Abiotic Stresses from the Microbiome of Alfalfa (Medicago sativa) in Saline and Arid Soils in Kerman Province. Iranian Journal of Soil and Water Research, https://doi.22059/ijswr.2023.356810.669471.
  2. Alkowni, R., Jodeh, S., Hamed, R., Samhan, S., and Daraghmeh, H. 2019. The impact of Pseudomonas putida UW3 and UW4 strains on photosynthetic activities of selected field crops under saline conditions. International Journal of Phytoremediation, 21: 944–952.
  3. Annicchiarico, P., Barrett, B., Brummer, E.C., Julier, B., and Marshall, A.H. 2015. Achievements and challenges in improving temperate perennial forage legumes. Critical Reviews in Plant Sciences, 34: 327–380.
  4. Bates, L., Waldren, R.P., and Teare, J.D. 1973. Rapid determination of free proline for water stress studies. Plant and Soil, 39: 205–207.
  5. 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.
  6. Bhattacharyya, A., Pablo, C.H.D., Mavrodi, O.V., Weller, D.M., Thomashow, L.S., and Mavrodi, D.V. 2021. Rhizosphere plant-microbe interactions under water stress. Advances in Applied Microbiology, 115: 65–113.
  7. Bhise, K.K., Bhagwat, P.K., and Dandge, P.B. 2017. Plant growth-promoting characteristics of salt tolerant Enterobacter cloacae strain KBPD and its efficacy in amelioration of salt stress in Vigna radiata L. Journal of Plant Growth Regulation, 36: 215–226.
  8. Bradford, M.M. 1976. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein binding. Analytical Biochemistry, 72: 248–254.
  9. Chatterjee, P., Samaddar, S., Anandham, R., Kang, Y., Kim, K., Selvakumar, G., and Sa, T. 2017. Beneficial soil bacterium Pseudomonas frederiksbergensis OS261 augments salt tolerance and promotes red pepper plant growth. Frontiers in Plant Science, 8: 705.
  10. Cordovilla, M., Ocana, A., Ligero, F., and Lluch, C. 1995. Salinity effects on growth analysis and nutrient composition in four grain legumes-rhizobium symbiosis. Journal of Plant Nutrition, 18: 1595–1609.
  11. Cramer, G.R., Urano, K., Delrot, S., Pezzotti, M., and Shinozaki, K. 2011. Effects of abiotic stress on plants: a systems biology perspective. BMC Plant Biology, 11: 163.
  12. Dey, G., Banerjee, P., Sharma, R.K., Maity, J.P., Etesami, H., Shaw, A.K., Huang, Y.H., Huang, H.B., and Chen, C.Y. 2021. Management of phosphorus in salinity-stressed agriculture for sustainable crop production by salt-tolerant phosphate-solubilizing bacteria. Agronomy, 11: 1552.
  13. Djebaili, R., Pellegrini, M., Rossi, M., Forni, C., Smati, M., Del Gallo, M., and Kitouni, M. 2021. Characterization of Plant Growth-Promoting traits and inoculation effects on Triticum durum of Actinomycetes isolates under salt stress conditions. Soil Systems, 5: 26.
  14. Estevez, J., Dardanelli, M., Megias, M., and Rodriguez-Navarro, D. 2009. Symbiotic performance of common bean and soybean co-inoculated with rhizobia and Chryseobacterium balustinum Aur9 under moderate saline conditions. Symbiosis, 49: 29–36.
  15. FAO, 2007. http://www.fao.org/docrep/010/a1075e/a1075e00.htm
  16. Farrar, K., Bryant, D., and Cope-Selby, N. 2014. Understanding and engineering beneficial plant–microbe interactions: plant growth promotion in energy crops. Plant Biotechnology Journal, 12: 1193–1206.
  17. Fitzpatrick, C.R., Mustafa, Z., and Viliunas, J. 2019. Soil microbes alter plant fitness under competition and drought. Journal of Evolutionary Biology, 32: 438–450.
  18. Forni, C., Duca, D., and Glick, B.R. 2017. Mechanisms of plant response to salt and drought stress and their alteration by rhizobacteria. Plant and Soil, 410: 335–356.
  19. Gaete, A., Pulgar, R., Hodar, C., Maldonado, J., Pavez, L., and Zamorano, D. 2021. Tomato cultivars with variable tolerances to water deficit differentially modulate the composition and interaction patterns of their rhizosphere microbial communities. Frontiers in Plant Science, 12: 688533.
  20. Ghosh, D., Sen, S., and Mohapatra, S. 2017. Modulation of proline metabolic gene expression in Arabidopsis thaliana under water-stressed conditions by a drought-mitigating Pseudomonas putida Annals of Microbiology, 67: 655–668.
  21. Glick, B.R. 2020. Beneficial Plant-Bacterial Interactions; Springer: Berlin/Heidelberg, Germany, 2020; 383p.
  22. Grattan, S., and Grieve, C. 1998. Salinity–mineral nutrient relations in horticultural crops. Scientia Horticulturae, 78: 127–157.
  23. Grayson, M. 2013. Agriculture and drought. Nature, 501: S1.
  24. Gupta, A., Bano, A., Rai, S., Kumar, M., Ali, J., Sharma, S., and Pathak, N. 2021. ACC deaminase producing plant growth promoting rhizobacteria enhance salinity stress tolerance in Pisum sativum. 3 Biotechnology, 11: 514.
  25. Heath, R.L. and Packer, L. 1968. Photoperoxidation in isolated chloroplasts. 1. Kinetics and stechiometry of fatty acid peroxidation. Archives in Biochemistry Biophysics, 125: 189-198.
  26. Hilker, M., Schwachtje, J., Baier, M., Balazadeh, S., Baurle, I., and Geiselhardt, S. 2016. Priming and memory of stress responses in organisms lacking a nervous system. Biological Reviews of the Cambridge Philosophical Society, 91: 1118–1133.
  27. Hone, H., Mann, R., Yang, G., Kaur, J., Tannenbaum, I., Li, T., Spangenberg, G., and Sawbridge, T. 2017. Profiling, isolation and characterization of beneficial microbes from the seed microbiomes of drought tolerant wheat. Scientific Reports, 7: 11916.
  28. Jebara, M., Drevon, J.J., and Aouani, M. 2001. Effects of hydroponic culture system and NaCl on interactions between common bean lines and native rhizobia from Tunisian soils. Agronomie, 21: 601–605.
  29. Kosova, K, Prasil, I.T., Vitamvas, P. 2013. Protein contribution to plant salinity response and tolerance acquisition. International Journal of Molecular Sciences, 14: 6757–6789.
  30. Kumar, M., Patel, M.K., Kumar, N., Bajpai, A.B., and Siddique, K.H.M. 2021. Metabolomics and molecular approaches reveal drought stress tolerance in plants. International Journal of Molecular Sciences, 22: 9108.
  31. Kumawat, K.C., Sharma, P., Nagpal, S., Gupta, R.K., Sirari, A., Nair, R.M., Bindumadhava, H., and Singh, S. 2021. Dual microbial inoculation, a game changer Bacterial biostimulants with multifunctional growth promoting traits to mitigate salinity stress in spring mungbean. Frontiers in Microbiology, 11: 600576.
  32. Lamaoui, M., Jemo, M., Datla, R., and Bekkaoui, F. 2018. Heat and drought stresses in crops and approaches for their mitigation. Frontiers in Chemistry, 6: 26.
  33. Latef, A.A.H., Abu Alhmad, M.F., Kordrostami, M., Abo-Baker, A.B.A.E., and Zakir, A. 2020. Inoculation with Azospirillum lipoferum or Azotobacter chroococcum reinforces maize growth by improving physiological activities under saline conditions. Journal of Plant Growth Regulation, 39: 1293–1306.
  34. Liu, C.H., Siew, W., Hung, Y.T., Jiang, Y.T., and Huang, C.H. 2021a. 1-Aminocyclopropane-1-carboxylate (ACC) deaminase gene in Pseudomonas azotoformans is associated with the amelioration of salinity stress in tomato. Journal of Agricultural and Food Chemistry, 69: 913–921.
  35. Liu, Q., Xie, S., Zhao, X., Liu, Y., Xing, Y., and Dao, J. 2021b. Drought sensitivity of sugarcane cultivars shapes rhizosphere bacterial community patterns in response to water stress. Frontiers in Microbiology, 12: 732989.
  36. Mavrodi, O.V., McWilliams, J.R., Peter, J.O., Berim, A., Hassan, K.A., and Elbourne, L.D.H. 2021. Root exudates alter the expression of diverse metabolic, transport, regulatory, and stress response genes in rhizosphere pseudomonas. Frontiers in Microbiology, 12: 651282.
  37. Miller, K.J., Wood, J.M. 1996. Osmoadaptation by rhizosphere bacteria. Annual Review of Microbiology, 50: 101–137.
  38. Munns, R., and Tester, M. 2008. Mechanisms of salinity tolerance. Annual Review of Plant Biology, 59: 651–681.
  39. Nguyen, D., Rieu, I., Mariani, C., and van Dam, N.M. 2016. How plants handle multiple stresses: hormonal interactions underlying responses to abiotic stress and insect herbivory. Plant Molecular Biology, 91: 727–740.
  40. Orozco-Mosqueda, M.C., Glick, B.R., and Santoyo, G. 2020. ACC deaminase in plant growth-promoting bacteria (PGPB): An efficient mechanism to counter salt in crops. Microbiological Research, 235: 126439.
  41. Pan, J., Peng, F., Xue, X., You, Q., Zhang, W., Wang. T., and Huang, C. 2019. The growth promotion of two salt-tolerant plant groups with PGPR inoculation: a meta-analysis. Sustainability, 11: 378.
  42. Pascale, A., Proietti, S., Pantelides, I.S., and Stringlis, I.A. 2019. Modulation of the root microbiome by plant molecules: the basis for targeted disease suppression and plant growth promotion. Frontiers in Plant Science, 10: 1741.
  43. Rabiei, Z., Hosseini, S.J., Pirdashti, H., and Hazrati, S. 2020. Physiological and biochemical traits in coriander affected by plant growth promoting rhizobacteria under salt stress. Heliyon, 6: e05321.
  44. Rady, M.M., El-Shewy, A.A., Seif El-Yazal, M., and Abdelaal, K.E. 2018. Response of salt-stressed common bean plant performances to foliar application of phosphorus (MAP). International Letters of Natural Science, 72.
  45. Santoyo, G., Gamalero, E., and Glick, B.R. 2021. Mycorrhizal-bacterial amelioration of plant abiotic and biotic stress. Front. Sustain. Food Systems, 5: 672881.
  46. Saraf, R., Saingar, S., Chaudhary, S., Chakraborty, D. 2018. Response of plants to salinity stress and the role of salicylic acid in modulating tolerance mechanisms: physiological and proteomic Approach. In: Vats S (ed) Biotic and abiotic stress tolerance in plants. Springer, Singapore, pp 103–136.
  47. Sessitsch, A., Hardoim, P., Doring, J., Weilharter, A., Krause, A., and Woyke, T. 2012. Functional characteristics of an endophyte community colonizing roots as revealed by metagenomic analysis. Molecular Plant Microbe Interactions, 25: 28–36.
  48. Silva, E.R., Zoz, J., Oliveira, C.E.S., Zuffo, A.M., Steiner, F., Zoz, T., and Vendruscolo, E.P. 2019. Can co-inoculation of Bradyrhizobium and Azospirillum alleviate adverse effects of drought stress on soybean (Glycine max L. Merrill.). Archives of Microbiology, 201: 325–335.
  49. Singh, R.P., and Jha, P.N. 2016. The Multifarious PGPR Serratia marcescens CDP-13 Augments induced systemic resistance and enhanced salinity tolerance of wheat (Triticum aestivum L.). PLOS ONE, 11: e0155026.
  50. Somogyi-Nelson, M. 1952. Notes on sugar determination. Journal of Biological Chemistry, 195: 19-23.
  51. Song, Y., Wilson, A.J., Zhang, X.C., Thoms, D., Sohrabi, R., and Song, S. 2021. FERONIA restricts pseudomonas in the rhizosphere microbiome via regulation of reactive oxygen species. Nature Plants, 7: 644–654.
  52. Soussi, M.; Santamaria, M.; Ocana, A.; Lluch, C. 2001. Effects of salinity on protein and lipopolysaccharide pattern in a salt-tolerant strain of Mesorhizobium ciceri. Journal of Applied Microbiology, 90: 476–481.
  53. Sun, H., Jiang, S., Jiang, C., Wu, C., Gao, M., and Wang, Q. 2021. A review of root exudates and rhizosphere microbiome for crop production. Environmental Science Pollution Research International, 28: 54497–54510.
  54. Turner, T.R., James, E.K., and Poole, P.S. 2013. The plant microbiome. Genome Biology, 14: 209.
  55. Ullah, A., Akbar, A., Luo, Q., Khan, A.H., Manghwar, H., and Shaban, M. 2019. Microbiome diversity in cotton rhizosphere under normal and drought conditions. Microbial Ecology, 77: 429–439.
  56. Upadhyay, S.K., and Singh, D.P. 2015. Effect of salt-tolerant plant growth-promoting rhizobacteria on wheat plants and soil health in a saline environment. Plant Biology, 17: 288–293.
  57. Wen, T., Zhao, M., Liu, T., Huang, Q., Yuan, J., and Shen, Q. 2020. High abundance of Ralstonia solanacearum changed tomato rhizosphere microbiome and metabolome. BMC Plant Biology, 20: 166.