Explore the vast range of titles available.

Less than 10% of the estimated average requirement (EAR) for iron and zinc is provided by consumption of storage roots of the staple crop cassava ( Manihot esculenta Crantz) in West African human populations. We used genetic engineering to improve mineral micronutrient concentrations in cassava. Overexpression of the Arabidopsis thaliana vacuolar iron transporter VIT1 in cassava accumulated three- to seven-times-higher levels of iron in transgenic storage roots than nontransgenic controls in confined field trials in Puerto Rico. Plants engineered to coexpress a mutated A. thaliana iron transporter (IRT1) and A. thaliana ferritin (FER1) accumulated iron levels 7–18 times higher and zinc levels 3–10 times higher than those in nontransgenic controls in the field. Growth parameters and storage-root yields were unaffected by transgenic fortification in our field data. Measures of retention and bioaccessibility of iron and zinc in processed transgenic cassava indicated that IRT1   +   FER1 plants could provide 40–50% of the EAR for iron and 60–70% of the EAR for zinc in 1- to 6-year-old children and nonlactating, nonpregnant West African women. Cassava, a staple crop consumed by 800 million people, is enriched in iron and zinc through genetic biofortification.

DNA methylation is important for the regulation of gene expression and the silencing of transposons in plants. Here we present genome-wide methylation patterns at single-base pair resolution for cassava (Manihot esculenta,cultivar TME 7), a crop with a substantial impact in the agriculture of subtropical and tropical regions. On average, DNA methylation levels were higher in all three DNA sequence contexts (CG, CHG, and CHH, where H equals A, T, or C) than those of the most well-studied model plantArabidopsis thaliana.As in other plants, DNA methylation was found both on transposons and in the transcribed regions (bodies) of many genes. Consistent with these patterns, at least one cassava gene copy of all of the known components ofArabidopsisDNA methylation pathways was identified. Methylation of LTR transposons (GYPSYandCOPIA) was found to be unusually high compared with other types of transposons, suggesting that the control of the activity of these two types of transposons may be especially important. Analysis of duplicated gene pairs resulting from wholegenome duplication showed that gene body DNA methylation and gene expression levels have coevolved over short evolutionary time scales, reinforcing the positive relationship between gene body methylation and high levels of gene expression. Duplicated genes with the most divergent gene body methylation and expression patterns were found to have distinct biological functions and may have been under natural or human selection for cassava traits.

Endogenous FLOWERING LOCUS T homolog MeFT1 was transgenically overexpressed under control of a strong constitutive promoter in cassava cultivar 60444 to determine its role in regulation of flowering and as a potential tool to accelerate cassava breeding. Early profuse flowering was recorded in-vitro in all ten transgenic plant lines recovered, causing eight lines to die within 21 days of culture. The two surviving transgenic plant lines flowered early and profusely commencing as soon as 14 days after establishment in soil in the greenhouse. Both transgenic lines sustained early flowering across the vegetative propagation cycle, with first flowering recorded 30-50 days after planting stakes compared to 90 days for non-transgenic controls. Transgenic plant lines completed five flowering cycles within 200 days in the greenhouse as opposed to twice flowering event in the controls. Constitutive overexpression of MeFT1 generated fully mature male and female flowers and produced a bushy phenotype due to significantly increased flowering-induced branching. Flower induction by MeFT1 overexpression was not graft-transmissible and negatively affected storage root development. Accelerated flowering in transgenic plants was associated with significantly increased mRNA levels of MeFT1 and the three floral meristem identity genes MeAP1, MeLFY and MeSOC1 in shoot apical tissues. These findings imply that MeFT1 encodes flower induction and triggers flowering by recruiting downstream floral meristem identity genes.

Background Morphogenic culture systems are central to crop improvement programs that utilize transgenic and genome editing technologies. We previously reported that CMD2-type cassava ( Manihot esculenta ) cultivars lose resistance to cassava mosaic disease (CMD) when passed through somatic embryogenesis. As a result, these plants cannot be developed as products for deployment where CMD is endemic such as sub-Saharan Africa or the Indian sub-continent. Result In order to increase understanding of this phenomenon, 21 African cassava cultivars were screened for resistance to CMD after regeneration through somatic embryogenesis. Fifteen cultivars were shown to retain resistance to CMD through somatic embryogenesis, confirming that the existing transformation and gene editing systems can be employed in these genetic backgrounds without compromising resistance to geminivirus infection. CMD2-type cultivars were also subjected to plant regeneration via caulogenesis and meristem tip culture, resulting in 25–36% and 5–10% of regenerated plant lines losing resistance to CMD respectively. Conclusions This study provides clear evidence that multiple morphogenic systems can result in loss of resistance to CMD, and that somatic embryogenesis per se is not the underlying cause of this phenomenon. The information described here is critical for interpreting genomic, transcriptomic and epigenomic datasets aimed at understanding CMD resistance mechanisms in cassava.

Cassava (Manihot esculenta Crantz) is a major staple food crop of the humid tropics. As a heterozygous, vegetatively propagated crop, robust transformation protocols must be developed for elite cultivars that allow predictable production of large numbers of independent transgenic plant lines. A high throughput Agrobacterium-mediated transformation system was developed for the elite East African farmer-preferred cassava cultivar TME 204 using the GFP visual marker gene. Inclusion of the antibiotic moxalactam in culture medium used to produce embryogenic target tissues prior to inoculation with Agrobacterium increased recovery of independent GFP-expressing transgenic callus lines by up to 113-fold compared to the control. Enhanced transformation was also observed when TME 204 tissues were pretreated with other cephalosporins, namely cefoperazone, cefoxitin, cefmetazole and cefotaxime. Similar but less dramatic increases in transformation efficiencies were seen for the West African cultivars Oko-iyawo and 60444 when pre-treated with moxalactam. Dilution of Agrobacterium suspensions used for co-culture was found to increase transformation efficiencies, resulting in regeneration at an average of 33 GFP-expressing TME 204 plants per cc settled cell volume at OD600 0.05, compared to 15 plants at the more commonly used OD600 0.5. The optimized transformation systems were successfully utilized for the integration of genetic constructs for disease resistance and nutritional enhancement into more than 750 plants of TME 204.

Tef (Eragrostis tef (Zucc.) Trotter) is a staple food crop for 70% of the Ethiopian population and is currently cultivated in several countries for grain and forage production. It is one of the most nutritious grains, and is also more resilient to marginal soil and climate conditions than major cereals such as maize, wheat and rice. However, tef is an extremely low-yielding crop, mainly due to lodging, which is when stalks fall on the ground irreversibly, and prolonged drought during the growing season. Climate change is triggering several biotic and abiotic stresses which are expected to cause severe food shortages in the foreseeable future. This has necessitated an alternative and robust approach in order to improve resilience to diverse types of stresses and increase crop yields. Traditional breeding has been extensively implemented to develop crop varieties with traits of interest, although the technique has several limitations. Currently, genome editing technologies are receiving increased interest among plant biologists as a means of improving key agronomic traits. In this review, the potential application of clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated proteins (CRISPR-Cas) technology in improving stress resilience in tef is discussed. Several putative abiotic stress-resilient genes of the related monocot plant species have been discussed and proposed as target genes for editing in tef through the CRISPR-Cas system. This is expected to improve stress resilience and boost productivity, thereby ensuring food and nutrition security in the region where it is needed the most.

In the version of this article initially published, a relevant work was not cited. The following sentence has been inserted following the sentence ending \"Aspergillus phytase\" in the third paragraph of the article: \"Overexpression of AtIRT1, AtNAS1 and bean FERRITIN in rice resulted in 3.8-fold higher iron and 1.8-fold higher zinc concentrations than in the wild-type control .\" A corresponding reference has been added: 12. Boonyaves, K., Wu, T. Y., Gruissem, W. & Bhullar, N. K. Enhanced grain iron levels in rice expressing an IRON-REGULATED METAL TRANSPORTER, NICOTIANAMINE SYNTHASE, and FERRITIN gene cassette. Front. Plant Sci. 8, 130 (2017). The error has been corrected in the HTML and PDF versions of the article.

Biodiesel is one of the promising biofuels to replace fossil fuels as a primary energy source for machineries and vehicles. It can be produced from various edible and non-edible plants seed oil. Dovyalis caffra is one of the indigenous fruits which contains high amount of non-edible oil (43.05%) in its seed parts. However, there is limited research on Dovyalis caffra non-edible seed oil for production of biodiesel. This research is aimed to produce biodiesel from Dovyalis caffra seed oil. The production process was done by transesterification of oil with methanol using base (NaOH) catalyst and the biodiesel percentage yield result became 96 ± 2.00. Physicochemical characterization (moisture, viscosity, acid value, saponification value, peroxide and free fatty acid) of Dovyalis caffra seed oil was conducted and their values became 0.046 ± 0.99, 42.90 ± 0.19, 0.57 ± 0.51, 193 ± 0.21, 2.7 ± 0.73 and 2.25 ± 1.02, respectively. Also, the physicochemical characterization (acid value, saponification value, iodine value, kinematic viscosity, flash point, pour point, ash content and cross caloric value) of produced biodiesel was conducted and the results indicted with values of 0.42 ± 0.01, 226 ± 0.57, 15.64 ± 2.13, 3.2 ± 0.02, 145, 2, 0.32 ± 0.82 and 10,748.0653, respectively. The results from the experiment shows that Dovyalis caffra seeds have more oil content with good oil quality for biodiesel production, which is a critical issue in the production process of qualified biodiesel.

This paper aims to investigate and characterize lightweight sisal fiber(SF)-reinforced geopolymer composite (SFRGC) materials to utilize instead of cement-based construction materials. The investigation targets the impact of independent factors on the compressive, splitting tensile strength, and water absorption of fiber-reinforced geopolymer composite. A Response Surface Methodology(RSM) with box Behnken design(BBD) was used for characterization and to obtain the significance level of the selected variables such as fiber volume (5%, 10%, and 15%), fiber length in mm (5, 20, and 35), and alkali concentration (8 M, 12 M, and 16 M). Best result for compressive strength was 21.5 Mpa with a respective interaction of variables fiber volume, fiber length, and alkali concentration (5%, 20 mm, and 8 M). The best result for splitting tensile strength was 4.6 Mpa respective interaction of variables of (15%, 35 mm, and 12 M) respectively. Best result for water absorption was 5.325% with the interaction of variables of (5%, 20 mm, and 8 M).

Post-transcriptional gene silencing is commonly observed in polyploid species and often poses a major limitation to plant improvement via biotechnology. Five plant viral suppressors of RNA silencing were evaluated for their ability to counteract gene silencing and enhance the expression of the Enhanced Yellow Fluorescent Protein (EYFP) or the β-glucuronidase (GUS) reporter gene in sugarcane, a major sugar and biomass producing polyploid. Functionality of these suppressors was first verified in Nicotiana benthamiana and onion epidermal cells, and later tested by transient expression in sugarcane young leaf segments and protoplasts. In young leaf segments co-expressing a suppressor, EYFP reached its maximum expression at 48-96 h post-DNA introduction and maintained its peak expression for a longer time compared with that in the absence of a suppressor. Among the five suppressors, Tomato bushy stunt virus-encoded P19 and Barley stripe mosaic virus-encoded γb were the most efficient. Co-expression with P19 and γb enhanced EYFP expression 4.6-fold and 3.6-fold in young leaf segments, and GUS activity 2.3-fold and 2.4-fold in protoplasts compared with those in the absence of a suppressor, respectively. In transgenic sugarcane, co-expression of GUS and P19 suppressor showed the highest accumulation of GUS levels with an average of 2.7-fold more than when GUS was expressed alone, with no detrimental phenotypic effects. The two established transient expression assays, based on young leaf segments and protoplasts, and confirmed by stable transgene expression, offer a rapid versatile system to verify the efficiency of RNA silencing suppressors that proved to be valuable in enhancing and stabilizing transgene expression in sugarcane.