Hongos endófitos: ventajas adaptativas que habitan en el interior de las plantas

Endophytic fungi often develop a systemic and mutually beneficial association with their hosts. A wide range of economically important plants have been reported to harbor endophytes. In these symbiotic mutualisms, both host and symbiont gain benefits from the association. The fungus obtains nutrients form its host and in return it provides protection from abiotic (environmental stresses) and biotic stresses (pest and insect attacks) to its host plant. Endophytes have been shown to confer enhanced fitness to their hosts such as enhanced tillering, drought tolerance, root growth, overall enhanced plant growth. This work describes the detection, isolation and genetic transformation of an endophytic fungus, Acremonium implicatum, from Brachiaria brizantha accession CIAT 6780. The results open possibilities for exploiting the qualities of an introduced gene as a reporter and study the interactions between A. implicatum and its host Brachiaria. Furthermore, it also provides options to use a transformed A. implicatum as a vehicle for production and delivery of gene products of agronomic interest into the host plant in order to enhance protective benefits and other traits of agronomic importance that will contribute to improved plant productivity. Key words: genetic transformation, gene reporter, green fluorescent protein (GFP), plant-endophyte interaction. Los hongos endófitos son organismos inherentes a las plantas que establecen una asociación específica con su hospedero para mutuo beneficio. Existen sinnúmero de especies vegetales de importancia económica que interactúan con especies de hongos endófitos. La planta provee al hongo alimento, hospedaje y protección; por su parte, aunque no hay certeza sobre los mecanismos de acción, los endófitos confieren gran potencial adaptativo a las especies vegetales hospederas frente a condiciones adversas que generen estrés, ya sean de tipo abiótico (salinidad, acidez) o biótico (ataque de plagas). Esta simbiosis otorga mayor habilidad competitiva a las plantas y permite una plena expresión de su potencial genético traducido en altas tasas de germinación, mejor densidad, más biomasa en los tejidos y mayor producción de semilla. Se reporta la detección, aislamiento y transformación del hongo filamentoso endófito Acremonium implicatum aislado de la accesión Ciat 6780 del pasto Brachiaria brizantha en el laboratorio del Programa de Patología de Forrajes del Ciat. El trabajo abre amplias posibilidades para el estudio de la interacción planta-endófito y permite explorar su potencial como un sistema alternativo de expresión de genes que confieran resistencia a plagas y enfermedades sin recurrir al uso de plantas transgénicas. En los hospederos, los endófitos transgénicos pueden ser usados como vehículo para la producción y entrega de productos generados a partir de genes de interés agronómico, cumpliendo funciones protectoras y proporcionando otras ventajas que se vean reflejadas en una mayor productividad de la planta. 

Overview of antimicrobial compounds from African edible insects and their associated microbiota

This review discusses advances in the identification and bioactivity analysis of insect antimicrobial peptides (AMP) compounds, with a focus on small molecules associated with the microbiota of selected African edible insects. These molecules could be used as templates for developing next-generation drugs to combat multidrug-resistant pathogens. Previous research indicates that each insect species produces a distinct antimicrobial peptide that acts against specific microorganisms. The article analyzes several likely AMP-producing insects and their compounds. Edible insect-produced AMPs/small molecules’ chemistry receives little attention as researchers have concentrated on the discovery of antibacterial and antifungal peptides/polypeptides in plants

Climate-Smart \u3cem\u3eBrachiaria\u3c/em\u3e Grasses for Improving Livestock Production in East Africa

Climate change is a global phenomenon with negative impacts severely felt by poor people in developing countries (Morton 2007). Across many parts of Africa, rural poor communities rely greatly for their survival on agriculture and livestock that are amongst the most climate-sensitive economic sectors. Climate-smart agriculture helps farmers to increase food production, become more resilient to climate change and reduce greenhouse gas (GHG) emissions. The main anthro-pogenic GHGs are carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O); they are critically important for regulating the Earth’s surface temperature. Inadequate quantity and quality of feed is a major constraint to livestock production, particularly during the dry seasons across Africa. The overall objective of this inter-institutional program is to increase feed availability in action areas of the target countries in East Africa (e.g. Kenya, Rwanda) by use of climate-smart Brachiaria forage grasses (Rao et al. 2011) for increased animal productivity and for generation of extra income to smallholder famers. An innovative programmatic approach will be used to reintroduce high quality, persistent and productive Brachiaria genotypes that were selected and improved in Latin America (Miles et al. 2004) back to Africa. These forage grasses will contribute to alleviate feed shortages, increase income to resource poor farmers, improve soil fertility, adapt to and mitigate climate change, increase milk and beef production, and as a result improve livelihoods and protect the environment

Harmonizing the agricultural biotechnology debate for the benefit of African farmers

The intense debate over agricultural biotechnology is at once fascinating, confusing and disappointing. It is complicated by issues of ethical, moral, socio-economic, political, philosophical and scientific import. Its vocal champions exaggerate their claims of biotechnology as saviour of the poor and hungry, while, equally loudly, its opponents declare it as the doomsday devil of agriculture. Sandwiched between these two camps is the rest of the public, either absorbed or indifferent. Biotechnology issues specific to the African public must include crop and animal productivity, food security, alleviation of poverty and gender equity, and must exclude political considerations. Food and its availability are basic human rights issues—for people without food, everything else is insignificant. Although we should discuss and challenge new technologies and their products, bringing the agricultural biotechnology debate into food aid for Africa where millions are faced with life-or-death situations is irresponsible. Agricultural biotechnology promises the impoverished African a means to improve food security and reduce pressures on the environment, provided the perceived risks associated with the technology are addressed. This paper attempts to harmonize the debate, and to examine the potential benefits and risks that agricultural biotechnology brings to African farmers. Key words: Agriculture, biotechnology, biotechnology debate, biotechnology and Africa, biotechnology issues, food security, poverty alleviation. African Journal of Biotechnology Vol.2(11) 2003: 394-41

Evolving dynamics of insect frass fertilizer for sustainable nematode management and potato production

Potato production faces major challenges from inadequate soil fertility, and nematode infestation, yet synthetic fertilizers and nematicides are costly and harmful to the environment. This study explored the potential of chitin-fortified black soldier fly-composted organic fertilizer (BSFCOF) as a multipurpose organic fertilizer amendment for enhancing potato yield and suppressing potato cyst nematodes (PCN). The BSFCOF was applied at a rate equivalent to 150 kg N ha-1 and fortified with chitin from black soldier fly pupal exuviae at inclusion rates equivalent to 0.5, 1, 2, 3, 4 and 5% chitin. Data were collected on potato growth characteristics, PCN population densities, and soil chemical properties for two growing cycles. Results showed that chitin fortified BSFCOF significantly improved potato growth parameters, chlorophyll concentration, marketable tuber yield and number of marketable tubers. The marketable tuber yield achieved using chitin-fortified BSFCOF was 70 – 362%, and 69 – 238% higher than the values achieved using unfertilized soil during the first and second growing cycles, respectively. Soil amendment with chitin-fortified BSFCOF significantly reduced the number of cysts per 200 g soil-1, number of eggs and J2 per cyst-1, eggs g-1 soil and reproduction rate by 32 – 87%, 9 – 92%, 31– 98% and 31 – 98%, respectively. The PCN suppression increased with chitin inclusion rates. There were significantly higher values for soil pH, ammonium nitrogen, nitrate nitrogen, available phosphorus, calcium, magnesium, potassium, and cation exchange capacity in soil amended with BSFCOF compared to unamended soil. This study demonstrates that BSFCOF fortified with 5% chitin is an effective soil enhancer with multiple benefits, including improved soil fertility, potato performance, and effective management of potato cyst nematodes

Molasses grass induces direct and indirect defense responses in neighbouring maize plants

Plants have evolved intricate defence strategies against herbivore attack which can include activation of defence in response to stress-related volatile organic compounds (VOCs) emitted by neighbouring plants. VOCs released by intact molasses grass (Melinis minutiflora), have been shown to repel stemborer, Chilo partellus (Swinhoe), from maize and enhance parasitism by Cotesia sesamiae (Cameron). In this study, we tested whether the molasses grass VOCs have a role in plant-plant communication by exposing different maize cultivars to molasses grass for a 3-week induction period and then observing insect responses to the exposed plants. In bioassays, C. partellus preferred non-exposed maize landrace plants for egg deposition to those exposed to molasses grass. Conversely, C. sesamiae parasitoid wasps preferred volatiles from molasses grass exposed maize landraces compared to volatiles from unexposed control plants. Interestingly, the molasses grass induced defence responses were not observed on hybrid maize varieties tested, suggesting that the effect was not simply due to absorption and re-emission of VOCs. Chemical and electrophysiological analyses revealed strong induction of bioactive compounds such as (R)-linalool, (E)-4,8-dimethyl-1,3,7-nonatriene and (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene from maize landraces exposed to molasses grass volatiles. Our results suggest that constitutively emitted molasses grass VOCs can induce direct and indirect defence responses in neighbouring maize landraces. Plants activating defences by VOC exposure alone could realize enhanced levels of resistance and fitness compared to those that launch defence responses upon herbivore attack. Opportunities for exploiting plant-plant signalling to develop ecologically sustainable crop protection strategies against devastating insect pests such as stemborer C. partellus are discussed

Harnessing data science to improve integrated management of invasive pest species across Africa: An application to Fall armyworm (Spodoptera frugiperda) (J.E. Smith) (Lepidoptera: Noctuidae)

After five years of its first report on the African continent, Fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) is considered a major threat to maize, sorghum, and millet production in sub-Saharan Africa. Despite the rigorous work already conducted to reduce FAW prevalence, the dynamics and invasion mechanisms of FAW in Africa are still poorly understood. This study applied interdisciplinary tools, analytics, and algorithms on a FAW dataset with a spatial lens to provide insights and project the intensity of FAW infestation across Africa. The data collected between January 2018 and December 2020 in selected locations were matched with the monthly average data of the climatic and environmental variables. The multilevel analytics aimed to identify the key factors that influence the dynamics of spatial and temporal pest density and occurrence at a 2 km x 2 km grid resolution. The seasonal variations of the identified factors and dynamics were used to calibrate rule-based analytics employed to simulate the monthly densities and occurrence of the FAW for the years 2018, 2019, and 2020. Three FAW density level classes were inferred, i.e., low (0–10 FAW moth per trap), moderate (11–30 FAW moth per trap), and high (>30 FAW moth per trap). Results show that monthly density projections were sensitive to the type of FAW host vegetation and the seasonal variability of climatic factors. Moreover, the diversity in the climate patterns and cropping systems across the African sub-regions are considered the main drivers of FAW abundance and variation. An optimum overall accuracy of 53% was obtained across the three years and at a continental scale, however, a gradual increase in prediction accuracy was observed among the years, with 2020 predictions providing accuracies greater than 70%. Apart from the low amount of data in 2018 and 2019, the average level of accuracy obtained could also be explained by the non-inclusion of data related to certain key factors such as the influence of natural enemies (predators, parasitoids, and pathogens) into the analysis. Further detailed data on the occurrence and efficiency of FAW natural enemies in the region may help to complete the tri-trophic interactions between the host plants, pests, and beneficial organisms. Nevertheless, the tool developed in this study provides a framework for field monitoring of FAW in Africa that may be a basis for a future decision support system (DSS).Harnessing data science to improve integrated management of invasive pest species across Africa: An application to Fall armyworm (Spodoptera frugiperda) (J.E. Smith) (Lepidoptera: Noctuidae)publishedVersio