Effect of Essential Oil Plant Extracts on in vitro Growth of Ralstonia solanacearum

Henry Oboo, Anastacia W. Muia, Z. M. Kinyua

Abstract


Ralstonia solanacearum is a soil-borne plant bacterial pathogen that causes wilting of affected plants. The disease is a major menace to many plants especially those from Solanaceae family that include potatoes and tomatoes which are major food crops. Control of bacterial wilt disease is generally very difficult as there are no effective curative chemicals. Furthermore the pathogen can survive as a latent infection in some non-host plants thus compounding control strategies. This study is aimed at investigating the potential roles of plant essential oils in managing this pathogen. Effects of each extract on growth of R. solanacearum was determined using a modified Kirby-Bauer disc diffusion method by impregnating filter discs with the extract and then placing them on an inoculated medium followed by incubation at different growth temperatures. The sizes of inhibition zones were measured and statistical analysis performed with the GenStat 12.1 (PC/Windows XP). Fisher’s protected least significant difference test was used to separate the means. Results demonstrated that essential oils extracted from Ocimum suave , Lippie javanica and Tarchonanthus camphorates possess antibacterial activity that is effective in control of R. solanacearum
at 24oC, 28oC and 32oC. Activity by O. suave was significantly higher
(P<0.05) compared to the other plants by producing largest inhibition zone of 5.78 ± 0.08mm at 24oC. In general the best activity at all incubation temperatures was in plates kept for 24 hours. An important finding is that essential oils activity against R. solanacearum did not indicate tendancy for disease resistance as was the case with chloramphenicol an antibiotic that was used as a positive control. This study shows that essential oil plants represent a rich potential source of alternative and perhaps environmentally acceptable disease management compound (s) that is active against R. solanacearum.

Key words: Antibacterial, Essential oils, Inhibition zone, Ralstonia
solanacearum, Wilting


Full Text:

PDF

References


Ajalie, A.N. and Okigbo, R.N. (2005). Inhibition of some human pathogens with tropical plants extracts Chromolaena odorata, Citrus aurantifolia and some antibiotics. Int. J. Mol, Med. Adv. Sci. 1:34-40

Ajanga, S. (1993). Status of bacterial wilt of potato in Kenya. In: G.L. Hartman and A.C.Hayward (Eds). Bacterial wilt. Aciar, Canberra, Australia, 338 –340.

Awuah, R.T. (1989). Fungi toxic effects of extracts from some West African plants. J. Applied Biology. 115,451- 453.

Baker, C.N., Thornsberry, C. and Hawkinson, R.W. (1983). Inoculum standardization in microbial susceptibility testing, evaluation of overnight agar cultures and the rapid inoculum standardization system. J. Clin. Microbiol. 17:450-457.

Birhanetensay, M., Eyasu, M., and Asfaw, D. (2012). In vivo anti-inflammatory activities of Ocimum Suave in mice. J. Sci. Ethnopharmacology. 142, 201-205.

Burt, S. (2004). Essential oils: their antibacterial properties and potential applications in food. J. Int. Food Microbiol, 94: 223-253

Cowan, M.M. (1999). Plant products as antimicrobial agents. J. Clin. Microbiol, 12, 564–582.

Deans, S.G. and Ritchie, G. (1987). Antibacterial properties of plant essential oils. J. Int. Food Microbiol. 5:165-180.

Elphinstone, J. G. (2005). The current bacterial wilt situation: a global overview. In: C. Allen, P. Prior and A. C. Hayward, (Eds.) Bacterial Wilt: The Disease and the Ralstonia solanacearum Species Complex. American Phytopathological Society, New York, USA, pp 9-28.

Janse, J.D. (1996). Potato brown rot in Western Europe history, present occurrence and some remarks on possible origin, epidemiology and control strategies. Bulletin OEPP/EPPO Bulletin 26, 679-695

Lopez, M.M. and Biosca, E.G. (2004).Potato bacterial wilt management: new prospects for an old problem. In: Allen C, Prior, P and Hayward, AC (Eds.). Bacterial Wilt Disease and Ralstonia species complex. APS press, St. Paul, Minnesota, USA, pp. 205-224

Momol, M.T., Olson, S.M., Pradhanang, P.M. and Jones, J.B. (2005). Evaluation of thymolasbiofumigant for control of bacterial wilt of tomato under field conditions. J. Plant Disease. 89: 497-500.

Ntezurubanza, L.I., Scheffer, J.C., A, Looman, A. and Sevendsen, A.B. (1988). Composition essential oil of Ocimum kilimandcharicum grown in Rwanda. J. Planta. Med. 50:385-388.

Nyangeri, J.B., Gathuru, E.M. and Mukunya, D.M. (1984). Effect of latent infection on the spread of bacterial wilt of potatoes in Kenya. J. Tropical Pest Management. 30, 163-165.

Ozcan, M.M., Sagdic, L. and Ozkan, O. (2006). Inhibitory effects of spice essential oils on the growth of Bacillus species. J. Med. Food. 9: 418-421

Palombo, E.A. and Semple, S.J. (2001). Antibacterial activity of traditional Australian medicinal plants. J. Ethnopharmacology. 77: 151-157.

Pradhanang, P.M., Momol, M.T., Olson, S.M. and Jones, J.B. (2003). Effects of plant essential oils on Ralstonia solanacearum population density and bacterial wilt incidence in tomato. J. Plant disease. 87:423-427.

Reiner, R., (1982). Combination of antibiotic, bactericidal and bacteriostatic antibiotics.

Roche sci. services, 8:86-87.

Sandra C. (2006). Chemical Constituents of Lippia scaberrima. (Verbenaceae). Tshwane University of technology Inc. Pretoria, South Africa. 327pp

Schaad, N.W., Jones, J.B. and Chun, W. (2001). Laboratory Guide for Identification of Plant Pathogenic Bacteria. American Phytopathological Society, Minnesota, U.S.A. PP 151-160. PP

Schell, M. A. (2000). Control of virulence and pathogenicity genes of Ralstonia solanacearum by an elaborate sensory network. Ann. Revi. Phytopathology. 38: 263–292.

Seenivasan, P., Manickkam, J. and Savarimuthu, I. (2006). In vitro antibacterial activity of some plant essential oils. J. Complementary and Alternative Medicine. 6:30-41.

Semple, S. J., Reynolds, G. D., Leary, M. C. and Flower, R. P. (1998). Screening of Australian medicinal plants for antiviral activity, J. Ethnopharmacology. 60:163-172

Stevenson, W.R., Loria, R., Franc, G.D. and Weingartner, D.P. (2001). Compendium of Potato diseases. APS Press, New York. PP. 217-222. .

Van Elsas, J.D., Van Overbeek, L.S., Bailey, M.J., Schönfeld, J. and Smalla, K. (2005). Fate of Ralstonia solanacearum biovar 2 as affected by conditions and soil treatments in temperate climate zones, The American Phytopathological Society. 65:39-49.

Van wyk, B., Van oudtshoorn, B. and Gericke, N. (1997). Medicinal plants of South Africa. Briza Publications Inc. Pretoria, South Africa. 200pp.

Wagura, A.G., Kimenju J.W. and Gichimu, B.M. (2011). Comparative antibacterial effects of raw extracts and essential oils of Ocimum gratissimum against Ralstonia solanacearum. International Journal of Plant Pathology. 2:144-152.

Yabuuchi, E., Kosako, Y., Yano, I., Hotta, H. and Nishiuchi, Y. (1995). Transfer of two Burkholderia and an Alcaligenes species to Ralstonia. J. Microbiol. Immunoogyl. 39: 897–904.


Refbacks

  • There are currently no refbacks.