Endophytic bacteria enhance the growth and salt tolerance of rice under saline conditions


  • Quang Trung DO Central Institute for Natural Resources and Environmental Studies, Vietnam National University Hanoi, Ha Noi, Vietnam
  • Anh The LUU Central Institute for Natural Resources and Environmental Studies, Vietnam National University Hanoi, Ha Noi, Vietnam
  • Tien Chuong NGO Central Institute for Natural Resources and Environmental Studies, Vietnam National University Hanoi, Ha Noi, Vietnam




endophytes, salt stress, plant growth-promoting bacteria, antioxidant enzymes, seed germination, rice (Oryza sativa)


Developing biostimulants from salt-tolerant plant growth-promoting (PGP) bacteria is an emerging strategy for sustainable agriculture in the context of increasing soil salinization. This study aimed to isolate endophytic bacteria (EB) capable of promoting rice seed germination and seedling growth at different NaCl concentrations. Nine salt-tolerant EB strains were isolated and two, ST.6 and ST.8, with the rice seed promoting effect 99.3 and 99.7 %, respectively, were selected and identified as Pantoea dispersa and Burkholderia cenocepacia, respectively. ST.6 showed a higher value of the activity of phosphatase (617 mg P ml-1), production of indole-3-acetic acid (19.7 µg IAA ml-1), the activity of 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase (13.5 µmol mg−1 protein h−1), and production of siderophore (76.3 %). Especially, rice seedlings inoculated with strain ST.6 showed a significant improvement in root length (58.95 %), shoot length (16.6 %), dry biomass (7.0 %), the content of chlorophyll (46.2 and 57.1 % for chlorophyll a and b, respectively), carotenoids (22.2%), and proline (19.0 %). A decrease in antioxidant enzyme activities was also observed in the rice seedlings inoculated with either ST.6 or ST.8 strain under salt stress. Furthermore, the salt stress condition enhanced the colonization of roots by both studied endophytic bacteria. More experiments should be done to develop endophytic bacteria ST.6 and ST.8 as efficient bio-inoculants.


Arora, N.K., Verma, M. (2017). Modified microplate method for rapid and efficient estimation of siderophore produced by bacteria. 3 Biotech, 7, 381. doi: 10.1007/s13205-017-1008-y

Abbas, R., Rasul, S., Aslam, K., Baber, M., Shahid, M., Mubeen, F., Naqqash, T. (2019).

Halotolerant PGPR: a hope for cultivation of saline soils. Journal of King Saud University – Science, 31(4), 1195-1201. doi: 10.1016/j.jksus.2019.02.019

Ben, J., Wolf, C., Rudiger, W. (1980). Chlorophyll biosynthesis: Hydrogenation of genanylgenaniol. Plant Science Letter, 19, 225-230. doi: 10.1016/0304-4211(80)90076-0

Bates, L.S., Waldren, R.P., Teare, I.D. (1973). Rapid determination of free proline for water-stress studies. Plant Soil, 39, 205–207. doi: 10.1007/BF00018060.

Bistgani, Z.E., Hashemi, M., DaCosta, M., Craker, L., Maggi, F., Morshedloo, M.R. (2019).

Effect of salinity stress on the physiological characteristics, phenolic compounds and antioxidant activity of Thymus vulgaris L. and Thymus daenensis Celak. Industrial Crops and Products, 135, 311-320. doi: 10.1016/j.indcrop.2019.04.055

Chu, C., Fan, M., Song, C., Li, N., Zhang, C., Fu, S., Wang, W., Yang, Z. (2021). Unveiling endophytic bacterial community structures of different rice cultivars grown in a cadmium-contaminated paddy field. Frontier in Microbiology, 12, 756327. doi: 10.3389/fmicb.2021.756327

Daliakopoulos, I.N., Tsanis, I.K., Koutroulis, A., Kourgialas, N.N., Varouchakis, A.E., Karatzas, G.P., Ritsema, C.J. (2016). The threat of soil salinity: a European scale review. Science of The Total Environment, 573, 727–739. doi: 10.1016/j.scitotenv.2016.08.177

Etesami, H., Glick, B.R. (2020). Halotolerant plant growth–promoting bacteria: prospects

for alleviating salinity stress in plants. Environmental and Experimental Botany, 104124. doi: 0.1016/j.envexpbot.2020.104124

Hao, S., Wang, Y., Yan, Y., Liu, Y., Wang, J., Chen, S. (2021). A Review on plant responses to salt stress and their mechanisms of salt resistance Horticulturae, 7, 132. doi: 10.3390/horticulturae7060132

Ilangumaran, G., Smith, D.L. (2017). Plant growth promoting rhizobacteria in amelioration of salinity stress: a systems biology perspective. Frontiers in Plant Science, 8, 1768. doi: 10.3389/fpls.2017.01768

Kumar, S., Stecher, G., Tamura, K. (2016). MEGA7: molecular evolutionary genetics analysis version 7.0 for bigger datasets. Molecular Biology and Evolution, 33(7), 1870–1874. doi: 10.1093/molbev/msw054

Kumar, V., Kumar, P., Khan, A. (2020). Optimization of PGPR and silicon fertilization using response surface methodology for enhanced growth, yield and biochemical parameters of French bean (Phaseolus vulgaris L.) under saline stress. Biocatalysis and Agricultural Biotechnology, 23, 101463. doi: 10.1016/j.bcab.2019.101463

Kumar, A., Singh, S., Mukherjee, A., Rastogi, R.P., Verma, J.P. (2021). Salt-tolerant plant growth-promoting Bacillus pumilus strain JPVS11 to enhance plant growth attributes of rice and improve soil health under salinity stress. Microbiological Research, 242, 126616. doi: 10.1016/j.micres.2020.126616

Lu, L., Chang, M., Han, X., Wang, Q., Wang, J., Yang, H., Guan, Q., Dai, S. (2021). Beneficial effects of endophytic Pantoea ananatis with ability to promote rice growth under saline stress. Journal of Applied Microbiology, 131(4), 1919-1931. doi: 10.1111/jam.15082

Liang, W., Ma, X., Wan, P., Liu, L. (2018). Plant salt-tolerance mechanism: A review. Biochemical and Biophysical Research Communications, 495(1), 286–291. doi:10.1016/j.bbrc.2017.11.043

Murphy, J., Riley, J.P. (1962). A modified single solution method for the determination of phosphate in natural waters. Analytica Chimica Acta, 27, 31-36. https://doi.org/10.1016/S0003-2670(00)88444-5

Mohammadkhani, N., Heidari, R. (2008). Drought-induced accumulation of soluble sugars and proline in two maize varieties. World Applied Sciences Journal, 3, 448-453.

Otlewska, A., Migliore, M., Dybka-Stezpien, K., Manfredini, A., Struszczyk-Swita, K., Napoli, R., Białkowska, A., Canfora, L., Pinzari, F. (2020). When salt meddles between plant, soil, and microorganisms. Frontiers in Plant Science, 11, 553087.

Patten, C.L., Glick, B.R. (2002). Role of Pseudomonas putida indole acetic acid in development of the host plant root system. Applied and Environmental Microbiology, 68, 3795-3801. doi: 10.3389/fpls.2020.553087

Penrose, D.M., Glick, B.R. (2003). Methods for isolating and characterizing ACC deaminase-containing plant growth-promoting rhizobacteria. Physiologia Plantarum, 118, 10-15. https://doi.org/10.1034/j.1399-3054.2003.00086.x

Rfaki, A., Zennouhi, O., Aliyat, F.Z., Nassiri, L., Ibijbijen, J. (2019). Isolation, selection and characterization of root-associated rock phosphate solubilizing bacteria in Moroccan wheat (Triticum aestivum L.). Geomicrobiology Journal, 37, 230-241. doi: 10.1080/01490451.2019.1694106

Radhakrishnan, R., Baek, K.H. (2017). Physiological and biochemical perspectives of non-salt tolerant plants during bacterial interaction against soil salinity. Plant Physiology and Biochemistry, 116, 116-126. doi: 10.1016/j.plaphy.2017.05.009

Rundlöf, M., Smith, H., Birkhofer, K. (2016). Effects of Organic Farming on Biodiversity, p.1-7. https://doi.org/10.1002/9780470015902.a0026342

Schulz, B., Boyle, C. (2007). What are Endophytes? In Soil Biology. Springer: Berlin/Heidelberg, Germany; p. 1–13. https://doi.org/10.1007/3-540-33526-9_1

Shultana, R., Zuan, A.T.K., Yusop, M.R., Saud, H.M. (2020). Characterization of salt-tolerant plant growth-promoting rhizobacteria and the effect on growth and yield of saline-affected rice. PLoS One, 15, e0238537. doi: 10.1371/journal.pone.0238537

Sun, L., Lei, P., Wang, Q., Ma, J., Zhan, Y., Jiang, K., Xu, Z., Xu, H. (2020). The endophyte Pantoea alhagi NX-11 alleviates salt stress damage to rice seedlings by secreting exopolysaccharides. Frontier in Microbiology, 10, 3112. doi: 10.3389/fmicb.2019.03112

Sarkar, A., Pramanik, K., Mitra, S., Soren, T., Maiti, T.K. (2018). Enhancement of growth and salt tolerance of rice seedlings by ACC deaminase-producing Burkholderia sp. MTCC 12259. Journal of Plant Physiology, 231, 434–442. doi: 10.1016/j.jplph.2018.10.010

Spaepen, S., Vanderleyden, J. (2011). Auxin and plant-microbe interactions. Cold Spring Harbor Perspectives in Biology, 3, a001438. doi: 10.1101/cshperspect.a001438

Tara, N., Arslan, M., Hussain, Z., Iqbal, M., Khan, Q.M., Afzal, M. (2019). On-site performance of floating treatment wetland macrocosms augmented with dye-degrading bacteria for the remediation of textile industry wastewater. Journal of Cleaner Production, 217, 541–548. doi: 10.1016/j.jclepro.2019.01.258

Trung, D.Q., Hang, N.T.T., Van, D.M., Ngoc, P.B., Anh, L.T. (2022). Screening of endophytic bacteria isolated from weed plant to biocontrol stem rot disease on pitaya (Hylocereus undatus). Brazilian Archives of Biology and Technology, 65, e22200749. doi: 10.1590/1678-4324-2022200749

Vaishnav, A., Shukla, A.K., Sharma, A., Kumar, R., Choudhary, D.K. (2019). Endophytic bacteria in plant salt stress tolerance: current and future prospects. Journal of Plant Growth Regulation, 38, 650-668. doi: 10.1007/s00344-018-9880-1

Wang, Q., Kanga, L., Lin, C., Song, Z., Tao, C., Liu, W., Yan, J. (2019a). Transcriptomic evaluation of Miscanthus photosynthetic traits to salinity stress. Biomass Bioenergy, 125, 123–130. doi: 10.1016/j.biombioe.2019.03.005

Wang, Z., Li, C., White, J. (2019b). Effects of Epichloë endophyte infection on growth, physiological properties and seed germination of wild barley under saline conditions. Journal of Agronomy and Crop Science, 206(1), 43-51. doi: 10.1111/jac.12366

Zhang, Z., Liu, T., Zhang, X., Xie, J., Wang, Y., Yan, R., Jiang, Y., Zhu, D. (2021). Cultivable endophytic bacteria in seeds of Dongxiang wild rice and their role in plant-growth promotion. Diversity, 13, 665. doi: 10.3390/d13120665



28. 04. 2023



Original Scientific Article

How to Cite

DO, Q. T., LUU, A. T., & NGO, T. C. (2023). Endophytic bacteria enhance the growth and salt tolerance of rice under saline conditions. Acta Agriculturae Slovenica, 119(1), 1–11. https://doi.org/10.14720/aas.2023.119.1.2899

Similar Articles

1-10 of 852

You may also start an advanced similarity search for this article.