Genic SNP markers and legume synteny reveal candidate genes underlying QTL for Macrophomina phaseolina resistance and maturity in cowpea [Vigna unguiculata (L) Walp.]

<p>Abstract</p> <p>Background</p> <p><it>Macrophomina phaseolina </it>is an emerging and devastating fungal pathogen that causes significant losses in crop production under high temperatures and drought stress. An increasing number of disease incidence reports highlight the wide prevalence of the pathogen around the world and its contribution toward crop yield suppression. In cowpea [<it>Vigna unguiculata </it>(L) Walp.], limited sources of low-level host resistance have been identified, the genetic basis of which is unknown. In this study we report on the identification of strong sources of host resistance to <it>M. phaseolina </it>and the genetic mapping of putative resistance loci on a cowpea genetic map comprised of gene-derived single nucleotide polymorphisms (SNPs) and amplified fragment length polymorphisms (AFLPs).</p> <p>Results</p> <p>Nine quantitative trait loci (QTLs), accounting for between 6.1 and 40.0% of the phenotypic variance (R²), were identified using plant mortality data taken over three years in field experiments and disease severity scores taken from two greenhouse experiments. Based on annotated genic SNPs as well as synteny with soybean (<it>Glycine max</it>) and <it>Medicago truncatula</it>, candidate resistance genes were found within mapped QTL intervals. QTL <it>Mac-2 </it>explained the largest percent R²and was identified in three field and one greenhouse experiments where the QTL peak co-located with a SNP marker derived from a pectin esterase inhibitor encoding gene. Maturity effects on the expression of resistance were indicated by the co-location of <it>Mac-6 </it>and <it>Mac-7 </it>QTLs with maturity-related senescence QTLs <it>Mat-2 </it>and <it>Mat-1</it>, respectively. Homologs of the <it>ELF4 </it>and <it>FLK </it>flowering genes were found in corresponding syntenic soybean regions. Only three <it>Macrophomina </it>resistance QTLs co-located with delayed drought-induced premature senescence QTLs previously mapped in the same population, suggesting that largely different genetic mechanisms mediate cowpea response to drought stress and <it>Macrophomina </it>infection.</p> <p>Conclusion</p> <p>Effective sources of host resistance were identified in this study. QTL mapping and synteny analysis identified genomic loci harboring resistance factors and revealed candidate genes with potential for further functional genomics analysis.</p

Heterotic Trait Locus (HTL) Mapping Identifies Intra-Locus Interactions That Underlie Reproductive Hybrid Vigor in Sorghum bicolor

Identifying intra-locus interactions underlying heterotic variation among whole-genome hybrids is a key to understanding mechanisms of heterosis and exploiting it for crop and livestock improvement. In this study, we present the development and first use of the heterotic trait locus (HTL) mapping approach to associate specific intra-locus interactions with an overdominant heterotic mode of inheritance in a diallel population using Sorghum bicolor as the model. This method combines the advantages of ample genetic diversity and the possibility of studying non-additive inheritance. Furthermore, this design enables dissecting the latter to identify specific intra-locus interactions. We identified three HTLs (3.5% of loci tested) with synergistic intra-locus effects on overdominant grain yield heterosis in 2 years of field trials. These loci account for 19.0% of the heterotic variation, including a significant interaction found between two of them. Moreover, analysis of one of these loci (hDPW4.1) in a consecutive F2 population confirmed a significant 21% increase in grain yield of heterozygous vs. homozygous plants in this locus. Notably, two of the three HTLs for grain yield are in synteny with previously reported overdominant quantitative trait loci for grain yield in maize. A mechanism for the reproductive heterosis found in this study is suggested, in which grain yield increase is achieved by releasing the compensatory tradeoffs between biomass and reproductive output, and between seed number and weight. These results highlight the power of analyzing a diverse set of inbreds and their hybrids for unraveling hitherto unknown allelic interactions mediating heterosis

Genomic designing of Pearl Millet: A resilient crop for arid and Semi-arid environments

Pearl millet [Pennisetum glaucum (L.) R. Br.; Syn. Cenchrus americanus (L.) Morrone] is the sixth most important cereal in the world. Today, pearl millet is grown on more than 30 million ha mainly in West and Central Africa and the Indian sub-continent as a staple food for more than 90 million people in agriculturally marginal areas. It is rich in proteins and minerals and has numerous health benefits such as being gluten-free and having slow-digesting starch. It is grown as a forage crop in temperate areas. It is drought and heat tolerant, and a climate-smart crop that can withstand unpredictable variability in climate. However, research on pearl millet improvement is lagging behind other major cereals mainly due to limited investment in terms of man and money power. So far breeding achievements include the development of cytoplasmic male sterility (CMS), maintenance counterparts (rf) system and nuclear fertility restoration genes (Rf) for hybrid breeding, dwarfing genes for reduced height, improved input responsiveness, photoperiod neutrality for short growing season, and resistance to important diseases. Further improvement of pearl millet for genetic yield potential, stress tolerance, and nutritional quality traits would enhance food and nutrition security for people living in agriculturally dissolute environments. Application of molecular technology in the pearl millet breeding program has a promise in enhancing the selection efficiency while shortening the lengthy phenotypic selection process ultimately improving the rate of genetic gains. Linkage analysis and genome-wide association studies based on different marker systems in detecting quantitative trait loci (QTLs) for important agronomic traits are well demonstrated. Genetic resources including wild relatives have been categorized into primary, secondary and tertiary gene pools based on the level of genetic barriers and ease of gene introgression into pearl millet. A draft on pearl millet whole genome sequence was recently published with an estimated 38,579 genes annotated to establish genomic-assisted breeding. Resequencing a large number of germplasm lines and several population genomic studies provided a valuable insight into population structure, genetic diversity and domestication history of the crop. Successful improvement in combination with modern genomic/genetic resources, tools and technologies and adoption of pearl millet will not only improve the resilience of global food system through on-farm diversification but also dietary intake which depends on diminishingly fewer crops

Anticancer Activity Stud-ies of Root Extract of Aloe Pirottae A. Berger En-demic Plant Species of Ethiopia

In an effort to find new anticancer agents from natural products, six crude methanol extracts and twenty-three organic solvent fractions, n-hexane (HxF), chloroform(CHF), ethyl acetate(EAF) and n-Butanol (BuF), from Aloe pirottea root an endemic medicinal plant of Ethiopia were investigated in vitro for their activities against A549, A2780, MIA-PaCa-2 and SNU-638 cancer cell lines at different concentrations including 0.1, 0.3, 1.0, 3.0, 10.0, and 30.0 µg/ml to determine the percentage of growth inhibition and IC50values using the sulforhodamine B (SRB) assay. The results were compared to standard anticancer drug Etoposide. Results demonstrated that all extracts exhibited anticancer activity with different degrees of potency. HxF, CHF and EAF of Aloe pirottea root extract showed good cytotoxic activity against A549, A2780 and SNU638 with IC50 value ranging from 6.37 to&nbsp; 29.69 µg/ml and, except for CHF of Aloe pirottea root with IC50 value of 18.86 µg/ml, all exhibited no or weak cytotoxic activity against MIA-PaCa-2 with IC50 value of &gt; 30.0 µg/ml. The highest cytotoxicity was found in the chloroform fraction. The responsiveness of solvent fraction to cell decreased as CHF &gt; EAF &gt; MeOH &gt; HxF &gt; BuF compared to reference standard anticancer drug Etoposide. The responsiveness of cell line to extracts were decreased as A-549 &gt; A2780 &gt; SNU-638 &gt; MIA-PaCa-2. It was found that the percentage growth inhibition increases with increasing concentration. This finding shows that the extracted fractions from this plant species can be used as a potential source for producing anticancer drugs

Outcome of tibial shaft fractures treated with the SIGN FIN nail at Addis Ababa Emergency, Burn, and Trauma Hospital (AaEBT) Addis Ababa, Ethiopia

Abstract. Objectives:. To determine the outcome of tibial fractures treated with the SIGN FIN nail. Study Design:. Retrospective case series study. Study Setting:. Trauma center. Methods and Materials:. We included 14 patients aged 18–51 years with 16 tibial fractures in this study. Patients were followed clinically and radiographically, and the minimum time followed was 6 months. Johner and Wruhs criteria with modification were used to assess the outcome. Result:. There were 11 male (78.6%) and three female (21.4%) patients. The mean age was 32.44 ± 8.98 (range 18–51) years. The right-sided tibia was injured in six as compared with the left side in four, and four patients had bilateral injuries. Eight (50%) fractures were closed fractures, whereas the rest eight (50%) were open types of fractures. Among the latter, half (n = 4; 50%) fractures were Gustilo type II fractures, while three (37.5%) fractures were Gustilo type III fractures, and one (12.5%) patient had a Gustilo type I fracture. All patients had radiologic union. There were no infections or secondary surgery for any reason. Excellent, good, and fair results were achieved in 62.5%, 25%, and 12.5%, respectively. All patients were able to return to their preinjury activity except two patients. Conclusion:. SIGN FIN nail is an option for treating tibial shaft fractures with good outcomes and few complications in selected fractures. Level of evidence:. Level I