RESUMEN
African locust bean (Parkia biglobosa) is a multipurpose leguminous tree species of nutritional and pharmacological value. The plant is widely distributed in Africa and across Nigeria's major agroecological areas (AEAs). Amidst declining cultivation and production, P. biglobosa is genetically threatened in its natural habitats due to overexploitation, deforestation, wildfires and lack of improved tree management practices. Consequently, concerted research efforts directed towards germplasm collection and assessment of genetic relationships are imperative for conserving its genetic resources, sustainable management and selecting promising landraces for breeding programmes. The dataset presents rbcL intraspecific genetic diversity and population structure of 62 P. biglobosa landraces in Nigeria. A relatively high level of diversity and a low degree of nucleotide variability was observed among the landraces. Relatively high values of 642 total allele sites, 601 polymorphic sites, 504 parsimony information sites, 883 total number mutations, 9 haplotypes and 0.55 gene diversity were recorded for the sequence dataset. Low values of 0.35 nucleotide diversity and 5 InDels events were also recorded for the dataset. The gene flow in this dataset demonstrated an extensive exchange of genes between the three populations of P. biglobosa, which influenced the level of genetic differentiation (Gst) between the populations. Significantly low Gst (-0.01) was recorded between the Guinea and Sudan savannah populations, a moderate value (0.03) was recorded between the Sudan savannah and Rainforest populations and a higher Gst value (0.05) was recorded between the Guinea and Rainforest populations. The dataset highlights potential evolutionary dynamics that might influence variations relevant to the breeding and conservation of P. biglobosa in Nigeria and across its range in West and Central Africa.
RESUMEN
Introduction: One of the unexpected outcomes of the COVID-19 pandemic was the relatively low levels of morbidity and mortality in Africa compared to the rest of the world. Nigeria, Africa's most populous nation, accounted for less than 0.01% of the global COVID-19 fatalities. The factors responsible for Nigeria's relatively low loss of life due to COVID-19 are unknown. Also, the correlates of protective immunity to SARS-CoV-2 and the impact of pre-existing immunity on the outcome of the COVID-19 pandemic in Africa are yet to be elucidated. Here, we evaluated the natural and vaccine-induced immune responses from vaccinated, non-vaccinated and convalescent individuals in Southern Nigeria throughout the three waves of the COVID-19 pandemic in Nigeria. We also examined the pre-existing immune responses to SARS-CoV-2 from samples collected prior to the COVID-19 pandemic. Methods: We used spike RBD and N- IgG antibody ELISA to measure binding antibody responses, SARS-CoV-2 pseudotype assay protocol expressing the spike protein of different variants (D614G, Delta, Beta, Omicron BA1) to measure neutralizing antibody responses and nucleoprotein (N) and spike (S1, S2) direct ex vivo interferon gamma (IFNγ) T cell ELISpot to measure T cell responses. Result: Our study demonstrated a similar magnitude of both binding (N-IgG (74% and 62%), S-RBD IgG (70% and 53%) and neutralizing (D614G (49% and 29%), Delta (56% and 47%), Beta (48% and 24%), Omicron BA1 (41% and 21%)) antibody responses from symptomatic and asymptomatic survivors in Nigeria. A similar magnitude was also seen among vaccinated participants. Interestingly, we revealed the presence of preexisting binding antibodies (N-IgG (60%) and S-RBD IgG (44%)) but no neutralizing antibodies from samples collected prior to the pandemic. Discussion: These findings revealed that both vaccinated, non-vaccinated and convalescent individuals in Southern Nigeria make similar magnitude of both binding and cross-reactive neutralizing antibody responses. It supported the presence of preexisting binding antibody responses among some Nigerians prior to the COVID-19 pandemic. Lastly, hybrid immunity and heterologous vaccine boosting induced the strongest binding and broadly neutralizing antibody responses compared to vaccine or infection-acquired immunity alone.