Detection of phytoplasma associated with Awka Wilt disease of coconut palms in Nigeria by polymerase chain reaction

This study was conducted to investigate the present of phytoplasma in coconut palms showing symptoms of Awka wilt disease or lethal yellowing disease (LYD) in Nigeria and determine if there is any geographical differentiation between the phytoplasma strains. Stem samples were collected from symptomatic coconut palms in five States namely; Anambra, Abia, Imo (in the south-east zone on Nigeria) and Edo and Akwa Ibom (in south-south zone of the coconut belt of Nigeria). DNA was extracted from the samples using cethyl trimethyl ammonium bromide (CTAB) protocol and the 16SrDNA was amplified by polymerase chain reaction (PCR) technique using the universal P1/P7 primers. The PCR products were sequenced and compared with each other. Five samples (NG12-30; NG12-36; NG12-37; NG12-43; NG12-44) out of the sixteen samples examined, yielded phytoplasma-specific 1,756 bp fragments when amplified with P1/P7 primers. A homology of 100% was observed between the sequences of the five samples based on the known conserved 16SrDNA sequences. The result of this study showed that phytoplasma was present in coconut palms that exhibited symptoms of Awka wilt disease and the phytoplasmas in the south-east and south-south zone of the country were the same strain. A similar investigation for symptomatic coconut from the western zone of the country is anticipated. (Résumé d'auteur