Occurrence of Awka wilt disease of coconut in Nigeria for one century

This study was conducted to characterize phytoplasmas from coconut palms showing symptoms of Awka wilt disease in south and south-east Nigeria and determine if there is geographic differentiation among the phytoplasma strains. Stem samples were collected from symptomatic coconut palms in three region of Nigeria. For each sample, DNA was extracted and the 16S rDNA was amplified by PCR by using the P1/P7 primers. Amplicons were sequenced for five Nigerian strains. The sequences were compared with each other, with LDN (lethal decline Nigeria) sequence published 20 years ago, and with sequences from Ghana. A homology of 100% was observed among the 16S rDNA sequence published and the sequences of the five strains under investigation. Based on the known conservation of 16S rDNA sequences, this result suggests a relative stability of the lethal yellowing disease phytoplasma strains in the southern regions of Nigeria, and no introduction of the “Ghanaian strain”. (Résumé d'auteur