eng Science and Education Publishing Journal of Applied & Environmental Microbiology 2373-6712 2020-03-29 8 1 25 31 10.12691/jaem-8-1-4 JAEM2020814 article OUATTARA Adama 1 COULIBALY Klotioloma 2 KONATE Ibrahim konatibrahim@yahoo.fr 2 KEBE Boubacar Isma?l 2 BEUGRE G.A. Maxwell 2 TIDOU Abiba Sanogo 2 Abdelkarim FILALI-MALTOUF 3 UFR Agro-forestry, Department of Biochemistry and Microbiology, Laboratory of Agrovalorization, Jean Lorougnon Guede University, B.P: 150 Daloa, C?te d¡¯Ivoire National Center for Agronomic Research (CNRA), Laboratory of Phytopathology, BP: 808 Divo, C?te d¡¯Ivoire Faculty of Sciences, Laboratory of Microbiology and Molecular Biology, University Mohammed V-Agdal, Rabat, Morocco We are investigating in this study the screening and selection of cocoa tree (Theobroma cacao L.) endophytic bacteria having antagonistic effects against the fungi Phytophthora spp. and to assess their inhibitory potential as biological control agents against black pod disease in Côte d'Ivoire. A total of One hundred and sixteen bacteria were isolated from symptomless root, leaf and stem tissues of two cocoa clones NA32 (susceptible) and P7 (resistant) young seedlings. These isolates restricted the radial growth of the mycelium of P. palmivora (strain BL7.11.2) and P. megakarya (strain 13P30.1) with percentages inhibition of 28.58 to 70.54% and 25.3 to 64.29% respectively. Four isolates, 48P, 60P, 23P and 18N were more effective in in vitro test and selected for in vivo confrontation test on leaf discs. Treatments based on two isolates S1 (48P) and S2 (18N) applied at the concentration 109 CFU/mL significantly (p < 0.05) reduced the black pod necrosis induced by the two Phytophthora strains on the leaf discs of three cocoa clones (NA32, PA150 and SCA6). In addition, simultaneous (C3PS1 and C3PS2) or separate (C3AVS1 and C3AVS2) inoculations of these two bacteria and Phytophthora, induced resistance to the clone NA32 and increased the intrinsic resistance of the clones PA150 and SCA6. This study showed that endophytic bacteria antagonistic to Phytophthora spp. can be an alternative solution in the biocontrol of black pod disease. In situ pod tests should be performed to confirm these preliminary results and propose effective bacterial inoculum. http://pubs.sciepub.com/jaem/8/1/4/jaem-8-1-4.pdf black pod phytophthora spp endophytic bacteria cocoa tree biocontrol