Molecular Identification of Phytophthora palmivora in the Cocoa Tree Orchard of Côte d’Ivoire and Assessment of the Quantitative Component of Pathogenicity

Author(s): Coulibaly Klotioloma, Aka Aka Romain, Brahima Camara, Kassin K. E., Koffie KOUAKOU, Kebe Boubacar Ismael, Koffi Kouassi Nazaire, Tahi Gnion Mathias, Walet Pierre N’GUESSAN, Brigitte GUIRAUD, Assi Maryse Evlyne, Kone Boake, K. F. N’Guessan, Kone Daouda

Black pod rot is one of the most widespread diseases in the species Theobroma cacao L. In Côte d’Ivoire, it causes significant yield losses, estimated at about 10 to 60% depending on the ecological zones. This study was conducted in order to identify Phytophthora spp isolates in the cocoa orchard by the analysis of their molecular features and assess their pathogenicity on cocoa tree leaf disks having different sensitivity. Thirty-six isolates of Phytophthora spp., from 06 producing regions (Divo, Soubré, Daloa, Duékoué, Abengourou and Aboisso) were taken from immature pods naturally affected by black pod rot. Methods of molecular analysis based on PCR-RFLP techniques, sequencing the ITS1 region of ribosomal DNA and artificial inoculation tests on cocoa tree leaf disks were used to identify Phytophthora isolates and assess their aggressiveness. The results obtained enabled to identify Phytophthora palmivora and showed a difference of aggressiveness between isolates of this species with average grades of foliar sensitivity ranging from 0.90 to 3.93.

Aggressiveness, Black Pod Rot, ITS-RFLP, Restriction Enzyme, Theobroma cacao

1. Abdelhadi H. (2003). Caractérisation de populations de phytophthora infestans (mont.) de bary dans la région de Saïs. Thèse de Doctorat de l’Université Sidi Mohammed Ibn Abdallah, 251p.
2. Appiah A.A, Flood J., Archer A., & Bridge P.D. (2003). Molecular analysis of the major Phytophthora species on cocoa. Plant Pathol. 53:209-219.
3. Babacauh K.D. (1980). Structure et dynamique des populations de Phytophthora sp. Parasite du cacaoyer (Theobroma cacao L.). Thèse de Doctorat d’Etat. Université de Paris –Sud, centre d’Orsay, 153 p.
4. Blaha G., & Lotodé R. (1982). Etude comparée du pouvoir pathogène sur semenceaux de Theobroma cacao des espèces de Phytophthora parasites du cacaoyer : analyse des éléments du pouvoir pathogène de Phytophthora palmivora et de P. megakarya. Café Cacao Thé, 25 (4): 237-266.
5. Brasier C.M., & Griffin M.J., (1979). Taxonomy of Phytophthora palmivora on cocoa. Transactions of the British Mycological Society 72, 111-43.
6. Cilas C., Lanaud C., Nyassé S., N’Goran J .A.K. Kebe B.I., Ducamp M., Flamant M. H., Risterucci A.M., Pieretti I., Sounigo O., Thevenin J.M., Despreaux D., 1998. La résistance à la pourriture brune des cabosses due à Phytophthora spp. Recherche des composantes de la résistance. Plantations Recherche Développement, 5 : 441- 446.
7. Cooke D.E.L., Drenth A., Duncan J.M., Wagels G., & Brasier C.M. (2000). A molecular phylogeny of Phytophthora and related Oomycetes. Fungal Genetics and Biology 30, 17–32.
8. Crawford, A. R., Bassam B. J., Drenth A., Maclean D. J., & Irwin J. A. G. (1996). Evolutionary relationships among Phytophthora species deduced from rDNA sequence analysis. Mycol. Res. 100(4):437-443.
9. Flood J. (2006). The threat from global spread of cocoa pests and diseases: hypothetical scenario or clear and present danger. In: Proceedings of the 15th International Cocoa Research Conference. 9-10 October 2006, San Jose (Costa Rica), pp.857-872.
10. Iwaro A.D., Sreenivasan T.N., & Umaharan P. (1998). Cacao resistance to Phytophthora: effect of pathogen species, inoculation and pod maturity. European Journal of Plant Pathology, 104: 11-15.
11. Kébé B. I., 1999. Rapport Annuel d’Activité 1998, Programme Café- Cacao- Cola, CNRA, Côte d’Ivoire, 39 p.
12. Lee, S. B., & Taylor J. W. (1992). Phylogeny of five Fungus-like Protoctistan Phytophthora species, lnferred from the Internal Transcribed Spacers of Ribosomal DNA. Mol. Biol. Evol. 9(4):636-653.
13. Martin, F. N. and P. W. Tooley. 2004. Identification of Phytophthora isolates to species level using restriction fragment length polymorphism analysis of a polymerase chain reaction amplified region of mitochondrial DNA. Phytopathology, 94: 983- 991.
14. Montarry J, Corbiere R, Lesueur S, Glais I. and Andrivon D. (2006). Does selection by resistant hosts triggers local adaptation in plant-pathogen systems. Journal of Evolutionary Biology, 19: 522- 531.
15. N’doumbe-Nkeng M. (1996). Traitement des données épidémiologiques sur la pourriture brune des cabosses du cacaoyer au Cameroun. Rapport de stage en Biométrie, Cirad-cp, Montpellier, France, 145 p.
16. Nyassé S. (1997). Etude de la diversité de Phytophthora megakarya et caractérisation de la résistance du cacaoyer (Theobroma cacao L.) à cet agent pathogène. Thèse de Doctorat, INP Toulouse, 113 p.
17. Nyassé S., Cilas C., Herail C., & Blaha G. (1995). Leaf inoculation as an early screening test for cocoa (Theobroma cacao L.) resistance to Phytophthora black pod disease. Crop Protection, 14 (8): 657 – 663.
18. Nyassé, S., D. Despréaux & Cilas C. (2002). Validity of a leaf inoculation test to assess the resistance to Phytophthora megakarya in cocoa (Theobroma cacao L.) diallel mating design. Euphytica, 123: 395-399.
19. Ortiz-Garcia C.F. (1996). Etude de la diversité génétique de populations de Phytophthora pathogens du cacaoyer (Theobroma cacao L.) et du cocotier (Cocos nucefera L). Thèse de Doctorat de l’université Paul Sabatier, 85 p.
20. Ploetz R. (2016). The impact of diseases on cacao production: a global overview, in Cacao Diseases: A History of Old Enemies and New Encounters, eds Bailey P. A., Meinhardt L. W., editors. (New York, NY: Springer International Publishing;), 33–59.
21. Ristaino JB, Madritch M, Truot CL, Parra G, (1998). PCR amplification of ribosomal DNA for species identification in the plant pathogen genus Phytophthora. Applied and Environmental Microbiology, 64: 948‐ 954.
22. Surujdeo-Maharaj S., Umaharan P., & Iwaro A.D. (2000). A study of genotype isolate interaction in cacao (Theobroma cacao L.): resistance of cacao genotype to isolates of Phytopthora palmivora. Euphytica, 118 : 295-303.
23. Tahi G. M., Kébé B. I., Sangare A., Mondeil F., Cilas C. and Eskes A. B. (2006). Foliar resistance of cacao (Theobroma cacao) to Phytophthora palmivora as an indicator of pod resistance in the field: interaction of cacao genotype, leaf age and duration of incubation. Plant Pathology 55, 776–782.
24. Torto,T., Li, S., Styer, A., Huitema, E., Testa, A., A. R. Gow, N., P. West, P. & Kamoun,S. (2007). EST mining and functional expression assays identity extracellular effector proteins from the plant pathogen Phytophthora. Genome Research 13; 1675- 1685.
25. Umaya A. 2004. Keragaman Genetik P. palmivora pada Kakao di Indonesia Berdasarkan Pendekatan Molekuler. Disertasi. Sekolah Pascasarjana IPB. Bogor. Menara Perkebunan, 74(2), 75-85.
26. Van der Vossen H. A. M., (1997). Strategies of variety improvement in cocoa with emphasis on durable disease resistance. In: Proceedings, International Workshop on the contribution of disease resistance to cocoa variety improvement, Salvador, Bahia, Brazil, pp: 27- 31.
27. White, T.J., T. Bruns, Lee S. & Taylor J.W. (1990). Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics. In Innis, M.A., D.H. Gelfand, J.J. Sninsky & T.J. White (eds.) PCR Protocol: A Guide to Methods and Applications. New York, Academic Press. p. 315-322.
28. Zéi P. (2002). Evaluation de la résistance du cacaoyer (Theobroma cacao L.) à Phytophthora sp, agent de la pourriture brune des cabosses : Etude de la spécificité parasitaire et des corrélations test feuilles - test cabosses. Mémoire de fin d’année pour l’obtention du Diplôme d’Agronomie Approfondie (DAA), INPHB, Yamoussoukro.62 p.