Abstract
Root-knot nematodes (Meloidogyne spp.) are among the most serious pests, reducing the yield and quality of tomatoes (Solanum lycopersicum) in Vietnam. Prolonged use of chemical pesticides has led to numerous negative impacts on the environment and human health. This study was conducted to select native Bacillus thuringiensis strains capable of controlling Meloidogyne spp. From soil samples collected from tomato fields in Danang, we isolated seven Bacillus strains, of which two strains, M2 and M5, were capable of producing toxic crystals. Strain M5 exhibited the highest inhibitory activity against Meloidogyne spp. J2 larvae in in vitro tests, achieving a mortality rate of 86.67% after 12 hours. Strain M5 was capable of producing key extracellular enzymes, including chitinase, protease, and cellulase. Sequencing of the 16S rRNA gene confirmed that strain M5 belongs to the species Bacillus thuringiensis (99.86% similarity with Bacillus thuringiensis MK743981.1). At a concentration of 10⁹ CFU/ml, strain M5 caused 100% mortality of J2 larvae after 10 hours and inhibited 88.9% of egg hatching. In greenhouse conditions, treatment with strain M5 significantly reduced the number of root galls on tomato plants (14.93 galls/plant) compared to the infected control (35.84 galls/plant). These results indicate that B. thuringiensis strain M5 is a promising biological control agent for managing root-knot nematodes on tomatoes.
References
- Seid A, Finance C, Celebrations T, Decraemer W, Wesemael WML. Tomato (Solanum lycopersicum) and root-knot nematodes (Meloidogyne spp.) – a century-old battle. Nematology. 2015;17(9):995-1009.
- Trudgill DL, Blok VC. Apomictic, polyphagous root-knot nematodes: exceptionally successful and damaging biotrophic root pathogens. Annu Rev Phytopathol. 2001;39:53-77.
- Nicol JM, Turner SJ, Coyne DL, Nijs Ld, Hockland S, Maafi ZT. Current Nematode Threats to World Agriculture. In: Jones J, Gheysen G, Fenoll C, editors. Genomics and Molecular Genetics of Plant-Nematode Interactions. Dordrecht: Springer Netherlands; 2011. p. 21-43.
- Sasser JN, Freckman DW. A world perspective on nematology: the role of the society. In: Veech JA, Dickson DW, editors. Vistas on nematology. Hyattsville (MD): Society of Nematologists; 1987. p. 7–14.
- Tien LTN, Thong DDV, Ngoc LTH, Tuan NNV, Nga NNTT, Sinh NV. Efficacy of biological agents against the root-knot nematode, (Meloidogyne incognita) infecting tomato under greenhouse conditions. Can Tho University Journal of Science. 2025;61(1):182-9.
- Vu TTT, Nguyen TAD, Nguyen TT. Study on use Endophytes for Enhancement of Tomato Toward Nematode Meloidogyne incognita in Vietnam. Biological Forum – An International Journal. 2016;8(1):268-272.
- Tran VT, Vo QTN, Dinh TQ, Nguyen KTV, Nguyen LTN, Nguyen TD, et al. Isolating a group of fungi from soil with the ability to control root-knot nematodes (Meloidogyne spp.) damage in vegetables. The Journal of Agriculture and Development. 2024;23(Special Issue 2):33-47.
- Hoang ND. Study on the selection of some antagonistic fungi against Meloidogyne spp. causing damage to pepper in Đăk Nông [Master’s thesis]. Tay Nguyen: University of Tay Nguyen; 2010.
- Borgonie G, Claeys M, Leyns F, Arnaut G, De Waele D, et al. Effect of nematicidal Bacillus thuringiensis strains on free-living nematodes. 1. Light microscopic observations, species and biological stage specificity and identification of resistant mutants of Caenorhabditis elegans. Fundam Appl Nematol. 1996;19:391-8.
- Zuckerman BM, Dicklow MB, Acosta N. Evaluation of Bacillus thuringiensis strain CR-371 for control of plant parasitic nematodes on tomato. J Nematol. 2008;40(4):273–8.
- Elsharkawy MM, Shimizu M, Takahashi H, Hyakumachi M. Control of tomato bacterial wilt and root-knot diseases by Bacillus thuringiensis CR-371 and Streptomyces avermectinius NBRC14893. J Plant Pathol Microbiol. 2015;6(5).
- Mohammed SH, El-Saedy MA, Enan MR, Ibrahim NE, Abdel-Razik AB. Biocontrol efficacy of Bacillus thuringiensis toxins against root-knot nematode, Meloidogyne incognita on tomato. Am-Eurasian J Agric Environ Sci. 2008;3(4):629-37.
- Nassiri Mahallati M, Pourrahim R, Moosavi SA. Isolation and identification of Bacillus species from rhizosphere soil and evaluation of their antagonistic effects on plant pathogens. J Crop Prot. 2017;6(4):531-42.
- Tenssay ZW, Ashenafi M, Eiler A, Bertilson S. Isolation and characterization of Bacillus thuringiensis from soils in contrasting agroecological zones of Ethiopia. Ethiop J Sci. 2009;32(2):117-28.
- Cappuccino JG, Sherman N. Microbiology: A Laboratory Manual. 10th ed. Boston: Pearson Education; 2014.
- Li Y, Liu Z, Zhao H, Xu Y, Cui F. Statistical optimization of xylanase production from new isolated Penicillium oxalicum ZH-30 in submerged fermentation. Biochem Eng J. 2007;34:82-6.
- López-Pérez JA, Flores-Rodríguez MD, Melero-Vara JM. A rapid and efficient method for extracting Meloidogyne incognita J2 from infected tomato roots. Nematropica. 2011;41(1):127-30.
- Yap CA. Screening for nematicidal activities of Bacillus species against root knot nematode (Meloidogyne incognita). Am J Exp Agric. 2013;3(4):794-805.
- Castric KF, Castric PA. Method for rapid detection of cyanogenic bacteria. Appl Environ Microbiol. 1980;45(2):701-2.
- Chahal PPK, Rana JS, Verma A. Effect of Bacillus thuringiensis isolates on egg hatching and larval development of Meloidogyne incognita. Nematologica. 1991;37(1):75-82.
- El-Kersh TA, Ahmed AM, Al-Sheikh YA, Tripet F, Turell MJ. Molecular characterization of Bacillus thuringiensis isolates from Saudi Arabia and their insecticidal activity against Aedes aegypti larvae. Trop Biomed. 2012;29(4):607-18.
- Ganga GC, Subashini S, Ramesh C. Isolation and characterization of Bacillus thuringiensis from soil samples and their toxicity against Helicoverpa armigera. Int J Curr Microbiol Appl Sci. 2018;7(2):392-401.
- Claus D, Berkeley RCW. Genus Bacillus Cohn 1872. In: Sneath PHA, Mair NS, Sharpe ME, Holt JG, editors. Bergey’s Manual of Systematic Bacteriology. Vol. 2. Baltimore: Williams & Wilkins; 1986. p. 1104-39.
- Bird AF. The structure of nematode egg shells. Nematologica. 1972;18:364-70.
- McConnell E, Richards AG. Production by Bacillus thuringiensis of a heat-stable insecticidal substance. Can J Microbiol. 1959;5:161-8.
- Chigaleichik AG. Chitinase of Bacillus thuringiensis. Mikrobiologiya. 1976;45:966-72.
- Marroquin LD, Elyassnia D, Griffitts JS, Feitelson JS, Aroian RV. Bacillus thuringiensis toxin susceptibility and isolation of resistance mutants in the nematode Caenorhabditis elegans. Genetics. 2000;155(4):1693-9.
- Khyami-Horani H. Biocontrol potential of Bacillus thuringiensis against the root-knot nematode Meloidogyne javanica on tomato plants. Plant Prot Sci. 2006;42(2):56-60.
- Granum PE, Pinnavaia SM, Ellar DJ. Comparison of Bacillus thuringiensis and Bacillus cereus enterotoxins in three different assay systems. Microbiology. 1988;134(5):1131-8.
- Ghareeb A, Abd-El-Khair H, El-Mougy NS, El-Katatny MH. Evaluation of Bacillus thuringiensis and some bioagents for controlling root-knot nematode (Meloidogyne incognita) on tomato plants under greenhouse conditions. J Plant Prot Res. 2013;53(3):280-5.
- Leyns F, DeCleene M, Swings J, DeLey J. The classification of Bacillus thuringiensis and other aerobic endospore-forming bacteria resembling B. thuringiensis. Int J Syst Bacteriol. 1995;35(4):408-16.
- Wei JZ, Hale K, Carta L, Platzer E, Wong C, Fang SC, et al. Bacillus thuringiensis crystal proteins that target nematodes. Proc Natl Acad Sci U S A. 2003;100(5):2760-5.
- Baghaee-Ravari S, Mahdikhani-Moghadam E, Ramezani-Moghadam S. Mechanism of Bacillus thuringiensis toxins against nematodes: A review. Int J Farming Allied Sci. 2015;4(8):687-93.

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