Detection and identification of the coconut lethal yellowing phytoplasma in weeds growing in coconut farms in C\uf4te d\u2019Ivoire

Coconut farms located in the southern coast of Grand-Lahou in C\uf4te d\u2019Ivoire are severely affected by a lethal yellowing disease (CILY) associated with the group 16SrXXII-B, \u2018Candidatus Phytoplasma palmicola\u2019-related strains. Given the high prevalence of weed species on most of the farms, plants growing within and in the periphery of five selected coconut farms were assessed for the presence of the CILY phytoplasma to identify potential alternative hosts. A total of 396 plant samples belonging to 84 plant species and 35 botanical families were collected. Total DNA was extracted and tested by nested PCR with primers targeting the 16S rRNA and the translocation protein (secA) phytoplasma genes, and sequenced. Twenty samples from six plant species and five botanical families yielded PCR amplicons of the expected size, and both the secA and 16S rDNA sequences showed over 99% similarity with that of the C\uf4te d\u2019Ivoire lethal yellowing phytoplasma previously identified from coconut palms grown in Grand-Lahou coconut farms. Plant species from the families Poaceae (Paspalum vaginatum, Pennisetum pedicillatum), Verbenaceae (Stachytarpheta indica), Plantaginaceae (Scoparia dulcis), Phyllanthaceae (Phyllantus muellerianus) and Cyperacea (Diplacrum capitatum) were positive for the presence of the CILY phytoplasma, suggesting they may have epidemiological implications for disease spread in coconut farms in Grand-Lahou

The C\uf4te d\u2019Ivoire lethal yellowing phytoplasma: towards improving diagnosis and disease management

The C\uf4te d\u2019Ivoire lethal yellowing (CILY) phytoplasma continues rapidly spreading into new coconut-growing villages, severely affecting the livelihoods of smallholder farmers in Grand-Lahou. Eight villages were surveyed for the CILY phytoplasma presence. Leaves, inflorescences and trunk borings were collected from symptomatic and symptomless coconut trees. Leaves from plant species growing within and in the periphery of the coconut farms were also collected. Total DNA was extracted and tested by nested PCR/RFLP and sequencing with primers targeting the 16S rRNA and the translocation protein (secA) phytoplasma genes. The CILY phytoplasma was detected in 81.2% of the symptomatic trees exhibiting symptoms of the disease stages 2 and 3 from all the villages surveyed, and was shown a trend to move westwards to other coconut-growing areas. CILY phytoplasma was distinguished from the Ghanaian Cape St. Paul Wilt Disease and the Mozambican LY phytoplasmas based on SecA RFLP profiles and SNPs. Plants from five botanical families: Poaceae, Verbenaceae, Plantaginaceae, Phyllanthaceae and Cyperacea were identified as alternative reservoirs for the CILY phytoplasma, which may have epidemiologic implications for the spread of CILY in the coconut farms in Grand-Lahou