Biology subjects

Abberton, M.

Publications and source records attributed to Abberton, M..

3 recordsLinked to original sources

bioRxiv2024

Morphological, pathological and phylogenetic analyses identify a diverse group of Colletotrichum spp. causing leaf, pod, and flower diseases on the orphan legume African yam bean

African yam bean (AYB; Sphenostylis stenocarpa Hochst. Ex A. Rich.) is an underutilized legume indigenous to Africa. The crop has great potential as it can enhance food security and its chemical composition offers nutritional and medicinal opportunities. However, the low grain yield caused by fungal diseases, including pod blight and leaf tip dieback, deters farmers from large-scale cultivation. The causal agents of pod and leaf tip dieback on AYB are largely uncharacterized. To determine the prevalence of fungal diseases affecting leaves, pods, and flowers of AYB, a survey was conducted in 2018 and 2019 in major AYB-growing areas in Nigeria. Leaf tip dieback, flower bud rot, and pod blight were the most common symptoms. Morphological and molecular assays were conducted to identify the causal agents of the observed diseases. In all the samples examined, fungi from eight genera were isolated from leaves and pods showing disease symptoms. However, Kochs postulates were fulfilled only for fungi belonging to the Colletotrichum genus. Fungi from the other seven genera did not produce disease symptoms in healthy AYB tissues. Several Colletotrichum isolates were characterized by sequencing the ITS, glyceraldehyde-3-phosphate dehydrogenase, calmodulin, and ApMAT loci. A combined phylogenetic analysis revealed four Colletotrichum species: C. siamense, C. theobromicola, and C. fructicola, which were recovered from the diseased leaves, and C. truncatum, which was recovered from diseased pods and buds. Our results are useful to gear efforts to develop integrated management strategies to control diseases affecting AYB in Nigeria and other parts of Africa. The availability of such strategies may stimulate greater cultivation of AYB to contribute to diet diversification, which has been repeatedly advocated by a range of stakeholders to increase food security and the prosperity of smallholder farmers.

microbiology↗

bioRxiv2023

The pattern of genetic variability in a core collection of 2,021 cowpea accessions

Cowpea is a highly drought-adapted leguminous crop with great promise for improving agricultural sustainability and food security. Here, we report analyses derived from array-based genotyping of 2,021 accessions constituting a core subset of the worlds largest cowpea collection, held at the International Institute of Tropical Agriculture (IITA) in Ibadan, Nigeria. We used this dataset to examine genetic variation and population structure in worldwide cowpea. We confirm that the primary pattern of population structure is two geographically defined subpopulations origining in West and East Africa, respectively, and that population structure is associated with shifts in phenotypic distribution. Furthermore, we establish the cowpea core collection as a resource for genome-wide association studies by mapping the genetic basis of several phenotypes, with a focus on seed coat pigmentation patterning and color. We anticipate that the genotyped IITA cowpea core collection will serve as a powerful tool for mapping complex traits, facilitating the acceleration of breeding programs to enhance the resilience of this crop in the face of rapid global climate change.

genetics↗

bioRxiv2023

Chromosome-scale assembly of the African yam bean genome

Genomics-informed breeding of locally adapted, nutritious, albeit underutilised African crops can help mitigate food and nutrition insecurity challenges in Africa, particularly against the backdrop of climate change. However, utilisation of modern crop improvement tools including genomic selection and genome editing for many African indigenous crops is hampered by the scarcity of genetic and genomic resources. Here we report on the assembly of the genome of African yam bean (Sphenostylis stenocarpa), a tuberous legume crop that is indigenous to Africa. By combining long and short read sequencing with Hi-C scaffolding, we produced a chromosome-scale assembly with an N50 of 69.5 Mbp and totalling 649 Mbp in length (77 - 81% of the estimated genome size based on flow cytometry). Using transcriptome evidence from Nanopore RNA-Seq and homology evidence from related crops, we annotated 31,614 putative protein coding genes. We further show how this resource improves anchoring of markers, genome-wide association analysis and candidate gene analyses in Africa yam bean. This genome assembly provides a valuable resource for genetic research in Africa yam bean.

genomics↗