AiM  Vol.4 No.10 , August 2014
Testing of Bacterial Endophytes from Non-Host Sources as Potential Antagonistic Agents against Tomato Wilt Pathogen Ralstonia solanacearum
ABSTRACT

The study was taken up with the objective of testing whether the endophytic organisms isolated from crops that are normally non-hosts to the bacterial wilt pathogen Ralstonia solanacearum possessed pathogen-antagonistic activity and to evaluate the selected isolates for the alleviation of wilt disease in the target tomato crop through horizontal movement of promising organisms. Sixteen endophytic bacteria (EB) isolated from the micropropagated cultures of grape, watermelon and papaya were tested for potential antagonistic effects against R. solanacearum tomato isolate “NH-01” through agar-well diffusion assay. Enterobacter cloacae from papaya (EB-11) displayed the maximum antagonistic effect followed by Bacillus subtilis (EB-06) and B. flexus (EB-07) from watermelon and B. pumilus (EB-02) from grape. Testing the above organisms for crop protection through seed fortification of susceptible tomato cv. Arka Vikas at sowing in R. solanacearum inoculated (Ral+) organic cocopeat showed EB-02 and EB-11 promising (33% and 32% survival, respectively, four weeks after sowing against 15% in Ral+ control). A second trial showed 37%, 28%, 21% and 55% seedling survival 6 weeks after sowing for EB-02, EB-06, EB-07 and EB-11 respectively, compared to 2.5% in non-treated control. Assessing the four endophytes for crop protection in Ral+ sick-soil through seedling fortification at transplanting indicated less disease incidence in treated sets (40%, 40%, 20% and 20% survival, respectively, six weeks after transplanting) over non-fortified control (5%). Endophytic fortification of seedlings through hypocotyl inoculation showed some systemic resistance induction upon seedling transplanting to sick soil but not with petiole fortification. Seedling growth was enhanced by the isolates EB-06 and EB-07. The study thus identifies four endophytic organisms from crops unrelated to tomato possessing potential antagonistic activity against the wilt pathogen and prospects for exploitation as biocontrol agents coupled with seedling growth promotion effects.


Cite this paper
Thomas, P. and Upreti, R. (2014) Testing of Bacterial Endophytes from Non-Host Sources as Potential Antagonistic Agents against Tomato Wilt Pathogen Ralstonia solanacearum. Advances in Microbiology, 4, 656-666. doi: 10.4236/aim.2014.410071.
References
[1]   Hayward, A.C. (1991) Biology and Epidemiology of Bacterial Wilt Caused by Pseudomonas solanacearum. Annual Review of Phytopathology, 29, 65-87.
http://dx.doi.org/10.1146/annurev.py.29.090191.000433

[2]   Elphinstone, J. (2005) The Current Bacterial Wilt Situation: A Global View. In: Allen, C., Prior, P., Hayward, A.C., Eds., Bacterial Wilt Disease and the Ralstonia solanacearum Species Complex, APS Press, St. Paul, 9-28.

[3]   Genin, S. and Denny, T.P. (2012) Pathogenomics of the Ralstonia solanacearum Species Complex. Annual Review of Phytopathology, 50, 67-89. http://dx.doi.org/10.1146/annurev-phyto-081211-173000

[4]   Patil, V.U., Gopal, J. and Singh, B.P. (2012) Improvement or Bacterial Wilt Resistance in Potato by Conventional and Biotechnological Approaches. Agricultural Research, 1, 299-316.
http://dx.doi.org/10.1007/s40003-012-0034-6

[5]   Chellemi, D.O., Dankers, H.A., Olson, S.M., Hodge, N.C. and Scott, J.W. (1994) Evaluating Bacterial Wilt-Resistant Tomato Genotypes Using a Regional Approach. Journal of American Society of Horticultural Science, 119, 325-329.

[6]   Ji, P., Momol, M.T., Rich, J.R., Olson, S.M. and Jones, J.B. (2007) Development of an Integrated Approach for Managing Bacterial Wilt and Root-Knot on Tomato under Field Conditions. Plant Disease, 91, 1321-1326. http://dx.doi.org/10.1094/PDIS-91-10-1321

[7]   Compant, S., Duffy, B., Nowak, J., Clément, C. and Barka, E.A. (2005) Use of Plant Growth-Promoting Bacteria for Biocontrol of Plant Diseases: Principles, Mechanisms of Action, and Future Prospects. Applied and Environmental Microbiology, 71, 4951-4959. http://dx.doi.org/10.1128/AEM.71.9.4951-4959.2005

[8]   Backman, P.A. and Sikora, R.A. (2008) Endophytes: An Emerging Tool for Biological Control. Biological Control, 46, 1-3. http://dx.doi.org/10.1016/j.biocontrol.2008.03.009

[9]   Tan, H., Zhou, S., Deng, Z., He, M. and Cao, L. (2011) Ribosomal-Sequence-Directed Selection for Endophytic Streptomycete Strains Antagonistic to Ralstonia Solanacearum to Control Tomato Bacterial Wilt. Biological Control, 59, 245-254. http://dx.doi.org/10.1016/j.biocontrol.2011.07.018

[10]   Guo, J.H., Qi, H.Y., Guo, Y.H., Ge, H.L., Gong, L.Y., Zhang, L.X. and Sun, P.H. (2004) Biocontrol of Tomato Wilt by Plant Growth-Promoting Rhizobacteria. Biological Control, 29, 66-72.
http://dx.doi.org/10.1016/S1049-9644(03)00124-5

[11]   Nguyen, M.T. and Ranamukhaarachchi, S.L. (2010) Soil-Borne Antagonists for Biological Control of Bacterial Wilt Disease Caused by Ralstonia solanacearum in Tomato and Pepper. Journal of Plant Pathology, 92, 395-406.

[12]   Maji, S. and Chakrabartty, P.K. (2014) Biocontrol of Bacterial Wilt of Tomato Caused by Ralstonia solanacearum by Isolates of Plant Growth Promoting Rhizobacteria. Australian Journal of Crop Science, 8, 208-214.

[13]   Vanitha, S.C., Niranjana, S.R., Mortensen, C.N. and Umesha, S. (2009) Bacterial Wilt of Tomato in Karnataka and Its Management by Pseudomonas fluorescens. BioControl, 54, 685-695.
http://dx.doi.org/10.1007/s10526-009-9217-x

[14]   Ramesh, R. and Phadke, G.S. (2012) Rhizosphere and Endophytic Bacteria for the Suppression of Eggplant Wilt Caused by Ralstonia solanacearum. Crop Protection, 37, 35-41.
http://dx.doi.org/10.1016/j.cropro.2012.02.008

[15]   Achari, G.A. and Ramesh, R. (2014) Diversity, Biocontrol, and Plant Growth Promoting Abilities of Xylem Residing Bacteria from Solanaceous Crops. International Journal of Microbiology, 2014, Article ID: 296521. http://dx.doi.org/10.1155/2014/296521

[16]   Rosenblueth, M. and Martinez-Romero, E. (2006) Bacterial Endophytes and Their Interactions with Hosts. Molecular Plant-Microbe Interactions, 19, 827-837. http://dx.doi.org/10.1094/MPMI-19-0827

[17]   Thomas, P. (2011) Intense Association of Non-Culturable Endophytic Bacteria with Antibiotic-Cleansed in Vitro Watermelon and Their Activation in Degenerating Cultures. Plant Cell Reports, 30, 2313-2325. http://dx.doi.org/10.1007/s00299-011-1158-z

[18]   Hallmann, J., Quadt-Hallmann, A., Mahaffee, W.F. and Kloepper, J.W. (1997) Bacterial Endophytes in Agricultural Crops. Canadian Journal of Microbiology, 43, 895-914. http://dx.doi.org/10.1139/m97-131

[19]   Tans-Kersten, J., Huang, H. and Allen, C. (2001) Ralstonia solanacearum Needs Motility for Invasive Virulence on Tomato. Journal of Bacteriology, 183, 3597-3605.
http://dx.doi.org/10.1128/JB.183.12.3597-3605.2001

[20]   White, J.F., Torres, M.A., Somu, M.P., Johnson, H., Irizarry, I., Chen Q., Zhang, N., Walsh, E., Tadych, M. and Bergen, M. (2014) Hydrogen Peroxide Staining to Visualize Intracellular Bacterial Infections of Seedling Root Cells. Microscopy Research and Technique, 77, 566-573.
http://dx.doi.org/10.1002/jemt.22375

[21]   Thomas, P. and Sekhar, A.C. (2014) Live Cell Imaging Reveals Extensive Intracellular Cytoplasmic Colonization of Banana Genotypes by Normally Non-Cultivable Endophytic Bacteria. AoB PLANTS, 6, plu002. http://dx.doi.org/10.1093/aobpla/plu002

[22]   Thomas, P. (2004) Isolation of Bacillus Pumilus from in Vitro Grapes as a Long-Term Alcohol-Surviving and Rhizogenesis Inducing Covert Endophyte. Journal of Applied Microbiology, 97, 114-123.

[23]   Thomas, P. (2006) Isolation of an Ethanol-Tolerant Endospore-Forming Gram-Negative Brevibacillus sp. as a Covert Contaminant in Grape Tissue Cultures. Journal of Applied Microbiology, 101, 764-774. http://dx.doi.org/10.1111/j.1365-2672.2006.02993.x

[24]   Thomas, P. (2007) Isolation and Identification of Five Alcohol Defying Bacillus spp. Covertly Associated with in Vitro Culture of Seedless Watermelon. Current Science, 92, 983-987.

[25]   Thomas, P., Kumari, S., Swarna, G.K. and Gowda, T.K.S. (2007) Papaya Shoot Tip Associated Endophytic Bacteria Isolated from in Vitro Cultures and Host-Endophyte Interaction in Vitro and in Vivo. Canadian Journal of Microbiology, 53, 380-390. http://dx.doi.org/10.1139/W06-141

[26]   Seshadri, K., Usman, K.M., Kandaswamy, T.K. and Seetharaman, K. (1977) Bacterial Wilt of Papaya Caused by Pseudomonas solanacearum. Madras Agricultural Journal, 64, 181-182.

[27]   Thomas, P., Sadashiva, A.T., Upreti, R. and Mujawar, M.M. (2014) Direct Delivery of Inoculum to Shoot Tissue Interferes with Genotypic Resistance to Ralstonia Solanacearum in Tomato Seedlings. Journal of Phytopathology, Early View. http://dx.doi.org/10.1111/jph.12281

[28]   Kelman, A. (1954) The Relationship of Pathogenicity of Pseudomonas solanacearum to Colony Appearance in a Tetrazolium Medium. Phytopathology, 44, 693-695.

[29]   Thomas, P. and Upreti, R. (2014) Influence of Seedling Age on Susceptibility of Tomato Plants to Ralstonia Solanacearum during Potray Screening and at Transplanting. American Journal of Plant Sciences, 5, 1755-1762. http://dx.doi.org/10.4236/ajps.2014.512190

[30]   Xue, Q.Y., Chen, Y., Li S.M., Chen L.F., Ding, G.C., Guo, D.W. and Guo, J.H. (2009) Evaluation of the Strains of Acinetobacter and Enterobacter as Potential Biocontrol Agents against Ralstonia Wilt of Tomato. Biological Control, 48, 252-258. http://dx.doi.org/10.1016/j.biocontrol.2008.11.004

[31]   Almoneafy, A.A., Xie, G.L., Tian, W.X., Xu, L.H. and Zhang, G.H. (2012) Characterization and Evaluation of Bacillus Isolates for their Potential Plant Growth and Biocontrol Activities against Tomato Bacterial Wilt. African Journal of Biotechnology, 11, 7193-7201.

[32]   Yang, Y., Xu, Q., Liu, H.X., Wang, Y.P., Wang W.M., Yang, H.T. and Gou, J.H. (2012) Evaluation of Biological Control Agents against Ralstonia Wilt on Ginger. Biological Control, 62, 144-151. http://dx.doi.org/10.1016/j.biocontrol.2012.05.001

[33]   Feng, H., Li, Y. and Liu, Q. (2013) Endophytic Bacterial Communities in Tomato Plants with Differential Resistance to Ralstonia solanacearum. African Journal of Microbiology Research, 7, 1311-1318.

[34]   Setlow, P. (2014) Germination of Spores of Bacillus Species: What We Know and Do Not Know. Journal of Bacteriology, 196, 1297-1305. http://dx.doi.org/10.1128/JB.01455-13

[35]   Lugtenberg, B. and Kamilova, F. (2009) Plant-Growth-Promoting Rhizobacteria. Annual Review of Microbiology, 63, 541-556. http://dx.doi.org/10.1146/annurev.micro.62.081307.162918

 
 
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