3 research outputs found
From coconut to cassava: the coconut lethal yellowing phytoplasma is worsening the threat to food security in C\uf4te d\u2019Ivoire
Background. Cassava (Manihot esculenta Crantz) is a major staple food in the developing countries whose
total world production reached approximately 278 million metric tonnes in 2017. C\uf4te d'Ivoire produces
around three million tonnes of cassava every year and reached 4.54 metric tonnes in 2017. It is typically
consumed as 'attiek\ue9', which is currently exported on regional and international markets. Cassava crop is now
threaten by the C\uf4te d'Ivoire lethal yellowing disease (CILY) first reported and associated with a phytoplasma
in Grand-Lahou in 2013. CILY destroyed over 400 ha of coconut groves in smallholder coconut farms where
women farmers started planting cassava as an alternative food and cash crop in coconut lands devastated by
the disease. Methods. Symptoms of leaf mosaic, curling and yellowing were observed in cassava orchards intwo coconut-growing villages located in the south coastal littoral of Grand-Lahou. Leaf samples were collected
from symptom-bearing and symptomless cassava plants and subjected to total DNA extraction. PCR with
phytoplasma universal 16S rRNA primers, and group-specific primers for subgroup 16SrXXII-B, \u2018Candidatus
Phytoplasma palmicola\u2019-related strains; and with specific primers for African/Eastern cassava mosaic viruses
(ACMV, EACMV). Amplicons were purified, cloned and sequenced. Sequences were compared to those of
reference in NCBI (https://www.ncbi.nlm.nih.gov) and used for phylogeny analysis of phytoplasma and virus
strains, respectively. Results. Phytoplasma DNA was amplified from six out of 12 symptom-bearing samples,
five of which co-amplified virus DNA. Phytoplasma sequences showed 99% identity to those of 16SrXXII-B
phytoplasmas as confirmed through phylogeny analysis. One cassava plant was co-infected with ACMV,
closely related to the Angola strain, while the other four showed co-infection with both the ACMV (Angola) and
an EACMV strain from Madagascar. All cassava varieties were phytoplasma-begomovirus co-infected, except
the Yac\ue9 variety. Conclusions. Cassava plants in Grand-Lahou orchards were found infected by CILY
phytoplasma (group 16SrXXII-B) and ACMV/EACMV virus strains. Results indicate that cassava may be an
alternative host for the CILY phytoplasma, which may play a role spreading and worsening CILY epidemic.
Prompt actions are required while waiting for a suitable resistant coconut cultivar. Short-term solutions may
include replanting cassava yards with newly developed cassava varieties that enhance plant resilience
against the coconut phytoplasma and ACMV/EACMV viruses to help supporting food production and improve
livelihoods of smallholder coconut farmers in Grand-Lahou
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