Biology subjects

Cisse, N.

Publications and source records attributed to Cisse, N..

3 recordsLinked to original sources

bioRxiv2018

The contrasting response to drought and waterlogging is underpinned by divergent DNA methylation programs associated with gene expression in sesame

DNA methylation is a heritable epigenetic mechanism that participates in gene regulation under abiotic stresses in plants. Sesame (Sesamum indicum L.) is typically considered a drought-tolerant crop but highly susceptible to waterlogging, a property attributed to its presumed origin in Africa or India. Understanding DNA methylation patterns in sesame under drought and waterlogging conditions can provide insights into the regulatory mechanisms underlying its contrasting responses to these principal abiotic stresses. Here, we combined Methylation-Sensitive Amplified Polymorphism and transcriptome analyses to profile cytosine methylation patterns, gene expression alteration, and their interplay in drought-tolerant and waterlogging-tolerant sesame genotypes under control, stress and recovery conditions. Our data showed that drought stress strongly induced de novo methylation (DNM) whereas most of the loci were demethylated (DM) during the recovery phase. In contrast, waterlogging decreased the level of methylation under stress but during the recovery phase, both DM and DNM were concomitantly deployed. In both stresses, the differentially expressed genes (DEGs) were highly correlated with the methylation patterns. We observed that DM was associated with the up-regulation of the DEGs while DNM was correlated with the down-regulation of the DEGs. In addition, we sequenced 44 differentially methylated regions of which 90% overlapped with the promoters and coding sequences of the DEGs. Altogether, we demonstrated that sesame has divergent epigenetic programs that respond to drought and waterlogging stresses. Our results also highlighted the possible interplay among DNA methylation and gene expression, which may modulate the contrasting responses to drought and waterlogging in sesame.

plant biology↗

bioRxiv2017

Identification of genetic factors controlling domestication-related traits in cowpea (Vigna unguiculata L. Walp)

Cowpea (Vigna unguiculata L. Walp) is a warm-season legume with a genetically diverse gene-pool composed of wild and cultivated forms. Cowpea domestication involved considerable phenotypic changes from the wild progenitor, including reduction of pod shattering, increased organ size, and changes in flowering time. Little is known about the genetic basis underlying these changes. In this study, 215 recombinant inbred lines derived from a cross between a cultivated and a wild cowpea accession were used to evaluate nine domestication-related traits (pod shattering, peduncle length, flower color, flowering time, 100-seed weight, pod length, leaf length, leaf width and seed number per pod). A high-density genetic map containing 17,739 single nucleotide polymorphisms was constructed and used to identify 16 quantitative trait loci (QTL) for these nine domestication-related traits. Candidate genes underlying each of those 16 QTL were identified. Four regions with clusters of QTL were identified, including one on chromosome 8 related to increased organ size. This study provides new knowledge of the genomic regions controlling domestication-related traits in cowpea as well as candidate genes underlying those QTL. This information can help to exploit wild relatives in cowpea breeding programs.\n\nKey messageThis study identified regions of the cowpea genome that played an important role in cowpea domestication, including a hotspot region for increased organ size

genetics↗

bioRxiv2017

A multi-parent advanced generation inter-cross population for genetic analysis of multiple traits in cowpea (Vigna unguiculata L. Walp.)

Development and analysis of Multiparent Advanced Generation Inter-Cross (MAGIC) populations have been conducted with several crop plants to harness the potential for dissecting the genetic structure of traits and improving breeding populations. We developed a first MAGIC population for cowpea (Vigna unguiculata L. Walp.) from eight founder parents which are genetically diverse and carry many abiotic and biotic stress resistance, seed quality and agronomic traits relevant to cowpea improvement in sub-Saharan Africa (SSA) where cowpea is vitally important in the human diet and in local economies. The eight parents were inter-crossed using structured matings to ensure the population would have balanced representation from each of the founder parents, followed by single-seed descent, resulting in 365 F8 recombinant inbred lines (RILs) each carrying a mosaic of genome blocks contributed from all founders. This was confirmed by SNP genotyping with the cowpea Illumina 60K iSelect BeadArray. Following filtering to eliminate duplicates, sister lines and accidental selfing events, a core set of 305 F8 RILs was chosen as the primary population. The F8 lines were on average 99.74% homozygous while also diverse in agronomic traits including flowering time, growth habit, maturity, yield potential and seed characteristics across environments. Trait-associated SNPs were identified for most of the parental traits. Loci with major effects on photoperiod sensitivity and seed size were also verified by genetic mapping in biparental RIL populations. The distribution of recombination frequency varied considerably between chromosomes, with recombination hotspots distributed mostly in the telomeric regions. Due to its broad genetic base, this cowpea MAGIC population promises breakthroughs in genetic gain and high-resolution genetic mapping for gene discovery, enhancement of breeding populations and, for some lines, direct releases as new varieties.

genetics↗