Biology subjects

Nebie, B.

Publications and source records attributed to Nebie, B..

5 recordsLinked to original sources

bioRxiv2026

Advancing Plant Health in Sub-Saharan Africa: Understanding National Agricultural Research Institutions capacities for Strategic Investment Priorities to Boost Genetic Gains Against Crop Biotic Stress

Plant health research within National Agricultural Research and Extension Systems (NARES) represents a critical yet neglected pillar of agricultural resilience in sub-Saharan Africa (SSA), where crop productivity remains substantially below global averages due to persistent biotic and abiotic stresses. Although plant health units have a strategic mandate to support crop protection, disease surveillance, and varietal improvement, the institutional capacity of these units across NARES in SSA is not defined. Here, we assessed 36 plant health units across 26 SSA countries to determine research capacity, identify operational constraints, and examine their contributions to crop improvement and food security. Our findings reveal the existence of a strong human capital operating under structurally constrained systems. More than 65% of personnel possess postgraduate qualifications, indicating the presence of a highly trained scientific workforce with considerable potential to drive plant health innovation. However, this expertise is undermined by severe infrastructural and institutional limitations that restrict research delivery. Access to essential facilities remains low, whereby only 53% of respondents had access to plant pathology laboratories, 43% had molecular biology platforms, and 37% had glass/screenhouses, while only 30% of respondents maintained phenotyping infrastructure such as sick plots or endemic/hot spot disease sites. These deficiencies undermine plant health research in areas like biotic stress resistance screening, pathogen diagnostics, and diversity. It was noted that plant health units primarily target staple food crops central to regional food systems, including cereals (maize, rice, sorghum, and millets), legumes (groundnut and cowpea), and root and tuber crops (cassava and potato). All these crops are affected by diverse biotic stresses that include fungi, bacteria, viruses, insect pests, and parasitic weeds. Yet research effectiveness to address these challenges is further constrained by unclear or fragmented protocols, poorly equipped laboratories, weak data capture, and management systems. Critical gaps were consistently identified in pathogen isolation and characterization, disease phenotyping, surveillance and mapping, experimental design, and data management. Workforce composition raises additional concerns regarding long-term system sustainability. Women account for only 18% of plant health personnel, while researchers younger than 35 years represent just 10% of the workforce, reflecting weak generational succession and gender inequity. These demographic imbalances constitute an existential threat to institutional continuity and innovation capacity. In summary, closing these gaps will require coordinated investment in infrastructure, technical training, institutional strengthening, and digital modernization. Equally important is the development of inclusive workforce strategies that improve gender representation and strengthen succession pathways. Unlocking the potential of NARES plant health networks is essential for accelerating resilient crop development, strengthening agricultural productivity, and advancing food security across SSA.

pathology↗

bioRxiv2025

Strigolactone effects on Sorghum bicolor ecophysiology and symbioses

Strigolactones are ecologically, developmentally, and physiologically important hormones, but much remains unknown about their evolution and role in non-model species. Sorghum is a globally important C4 cereal and exhibits natural variation in root-exuded strigolactones. Differences in sorghum strigolactone stereochemistry are associated with resistance to parasitic plants, but with evidence for potential trade-offs. We studied sorghum mutants of loci in the strigolactone biosynthetic pathway, CAROTENOID CLEAVAGE DIOXYGENASE 8 (SbCCD8b) and LOW GERMINATION STIMULANT 1 (LGS1), previously shown to be Striga resistant by stimulating little germination of the parasite. SbCCD8b CRISPR-Cas9 deletions changed the accumulation of low abundance metabolites, reduced net carbon assimilation rate, altered root architecture and anatomy, and diminished the establishment and benefit of mycorrhizal symbionts. For Striga-resistant LGS1 CRISPR-Cas9 deletions, differentially expressed genes were enriched with promoter motifs for stress response and growth pathways, net carbon assimilation rate was reduced, and the colonization of mycorrhizal symbionts was delayed. We additionally restored functional LGS1 into the RTx430 genetic background, which normally has the lgs1-2 natural deletion allele. While root exudates from LGS1 insertion mutants rescued Striga susceptibility, we did not see consistent rescue of other traits impacted in LGS1 loss-of-function mutants. We hypothesize that epistasis with a neighboring strigolactone synthesis gene, which is rarely lost without concomitant loss of LGS1, may alter the phenotypic effects of LGS1 variation. Our study gives context to potential trade-offs associated with host resistance to parasitic plants and, more broadly, builds on the contribution of strigolactones in shaping sorghum physiological processes, growth, and development.

plant biology↗

bioRxiv2023

Characterization of adaptation mechanisms in sorghum using a multi-reference back-cross nested association mapping design and envirotyping

The identification of haplotypes influencing traits of agronomic interest, with well-defined effects across environments, is of key importance to develop varieties adapted to their context of use. It requires advanced crossing schemes, multi-environment characterization and relevant statistical tools. Here we present a sorghum multi-reference back-cross nested association mapping (BCNAM) population composed of 3901 lines produced by crossing 24 diverse parents to three elite parents from West and Central Africa (WCA-BCNAM). The population was characterized in environments contrasting for photoperiod, rainfall, temperature, and soil fertility. To analyse this multi-parental and multi-environment design, we developed a new methodology for QTL detection and parental effect estimation. In addition, envirotyping data were mobilized to determine the influence of specific environmental covariables on the genetic effects, which allowed spatial projections of the QTL effects. We mobilized this strategy to analyse the genetic architecture of flowering time and plant height, which represent key adaptation mechanisms in environments like West Africa. Our results allowed a better characterisation of well-known genomic regions influencing flowering time concerning their response to photoperiod with Ma6 and Ma1 being photoperiod sensitive and candidate gene Elf3 being insensitive. We also accessed a better understanding of plant height genetic determinism with the combined effects of phenology dependent (Ma6) and independent (qHT7.1 and Dw3) genomic regions. Therefore, we argue that the WCA-BCNAM constitutes a key genetic resource to feed breeding programs in relevant elite parental lines and develop climate-smart varieties.

genetics↗

bioRxiv2022

DeepVariant calling provides insights into race diversity and its implication for sorghum breeding

Due to evolutionary divergence, sorghum race populations exhibit vast genetic and morphological variations. A k-mer-based sorghum race sequence comparison identified the conserved k-mers of all sorghum race accessions and the race-specific genetic signatures identified the gene variability in 10,321 genes (PAVs). To understand the sorghum race structure, diversity and domestication, deep learning-based variant calling approach was employed in a set of genotypic data derived from a diverse panel of 272 sorghum accessions. The data resulted in 1.7 million high-quality genome-wide SNPs and identified selective signature (both positive and negative) regions through a genome-wide scan with different (iHS and XP-EHH) statistical methods. We discovered 2,370 genes associated with selection signatures including 179 selective sweep regions distributed over 10 chromosomes. Localization of these regions undergoing selective pressure with previously reported QTLs and genes revealed that the signatures of selection could be related to the domestication of important agronomic traits such as biomass and plant height. The developed k-mer signatures will be useful in the future to identify the sorghum race and SNP markers assist in plant breeding programs.

plant biology↗

bioRxiv2021

Sorghum pan-genome explores the functional utility to accelerate the genetic gain

Sorghum (Sorghum bicolor L.) is one of the most important food crops in the arid and rainfed production ecologies. It is a part of resilient farming and is projected as a smart crop to overcome the food and nutritional challenges in the developing world. The development and characterisation of the sorghum pan-genome will provide insight into genome diversity and functionality, supporting sorghum improvement. We built a sorghum pan-genome using reference genomes as well as 354 genetically diverse sorghum accessions belonging to different races. We explored the structural and functional characteristics of the pan-genome and explain its utility in supporting genetic gain. The newly-developed pan-genome has a total of 35,719 genes, a core genome of 16,821 genes and an average of 32,795 genes in each cultivar. The variable genes are enriched with environment responsive genes and classify the sorghum accessions according to their race. We show that 53% of genes display presence-absence variation, and some of these variable genes are predicted to be functionally associated with drought traits. Using more than two million SNPs from the pan-genome, association analysis identified 398 SNPs significantly associated with important agronomic traits, of which, 92 were in genes. Drought gene expression analysis identified 1,788 genes that are functionally linked to different conditions, of which 79 were absent from the reference genome assembly. This study provides comprehensive genomic diversity resources in sorghum which can be used in genome assisted crop improvement.

bioinformatics↗