RESUMO

In Southeast Asia (SEA) fastidious fungi of the Ceratobasidium genus are associated with proliferation of sprouts and vascular necrosis in cacao and cassava, crops that were introduced from the tropical Americas to this region. Here, we report the isolation and in vitro culture of a Ceratobasidium sp. isolated from cassava with symptoms of witches' broom disease (CWBD), a devastating disease of this crop in SEA. The genome characterization using a hybrid assembly strategy identifies the fungus as an isolate of the species C. theobromae, the causal agent of vascular streak dieback of cacao in SEA. Both fungi have a genome size > 31 Mb (G+C content 49%), share > 98% nucleotide identity of the Internal Transcribed Spacer (ITS) and > 94% in genes used for species-level identification. Using RNAscope® we traced the pathogen and confirmed its irregular distribution in the xylem and epidermis along the cassava stem, which explains the obtention of healthy planting material from symptom-free parts of a diseased plant. These results are essential for understanding the epidemiology of CWBD, as a basis for disease management including measures to prevent further spread and minimize the risk of introducing C. theobromae via long-distance movement of cassava materials to Africa and the Americas.

Assuntos

RESUMO

There are few records for Telenomus dilophonotae Cameron, 1913 (Hymenoptera, Scelionidae) from South America. In Brazil, the first occurrence was reported in Bahia in rubber crops, Hevea brasiliensis (Willd. ex Adr. de Juss.) Muell. - Arg., there parasitizing eggs of Erinnyis ello Linnaeus, 1758 (Lepidoptera, Sphingidae). It was also found parasitizing the same host in cassava, Manihot esculenta Crantz (Euphorbiaceae). This is the first record of occurrence of T. dilophonotae in the state of Paraná, parasitizing eggs of E. ello in areas of cassava production in the western region of Paraná, this being the southernmost record of the species. Here, photographs, the first sequence of DNA barcode of this species of parasitoid wasp, and a distribution map are provided.

RESUMO

Cooking time is a crucial determinant of culinary quality of cassava roots and incorporating it into the early stages of breeding selection is vital for breeders. This study aimed to assess the potential of near-infrared spectroscopy (NIRS) in classifying cassava genotypes based on their cooking times. Five cooking times (15, 20, 25, 30, and 40 minutes) were assessed and 888 genotypes evaluated over three crop seasons (2019/2020, 2020/2021, and 2021/2022). Fifteen roots from five plants per plot, featuring diameters ranging from 4 to 7 cm, were randomly chosen for cooking analysis and spectral data collection. Two root samples (15 slices each) per genotype were collected, with the first set aside for spectral data collection, processed, and placed in two petri dishes, while the second set was utilized for cooking assessment. Cooking data were classified into binary and multiclass variables (CT4C and CT6C). Two NIRs devices, the portable QualitySpec® Trek (QST) and the benchtop NIRFlex N-500 were used to collect spectral data. Classification of genotypes was carried out using the K-nearest neighbor algorithm (KNN) and partial least squares (PLS) models. The spectral data were split into a training set (80%) and an external validation set (20%). For binary variables, the classification accuracy for cassava cooking time was notably high ( R C a l 2 ranging from 0.72 to 0.99). Regarding multiclass variables, accuracy remained consistent across classes, models, and NIR instruments (~0.63). However, the KNN model demonstrated slightly superior accuracy in classifying all cooking time classes, except for the CT4C variable (QST) in the NoCook and 25 min classes. Despite the increased complexity associated with binary classification, it remained more efficient, offering higher classification accuracy for samples and facilitating the selection of the most relevant time or variables, such as cooking time ≤ 30 minutes. The accuracy of the optimal scenario for classifying samples with a cooking time of 30 minutes reached R C a l 2   = 0.86 and R V a l 2 = 0.84, with a Kappa value of 0.53. Overall, the models exhibited a robust fit for all cooking times, showcasing the significant potential of NIRs as a high-throughput phenotyping tool for classifying cassava genotypes based on cooking time.

RESUMO

This work proposes the pyrolysis of the cassava plant shoot system biomass and a comprehensive chemical characterization of the resulting bio-oil. The highest yields of liquid products were obtained at 600 °C, with 12.6 % bio-oil (organic fraction), which presented the lowest total acid number of 65.7 mg KOH g-1. The bio-oil produced at 500 °C exhibited the highest total phenolic content of approximately 41 % GAE, confirmed by GC/MS analysis (33.8 % of the total area). FT-Orbitrap MS analysis found hundreds of oxygenated constituents in the bio-oils, belonging to the O2-7 classes, as well as nitrogen compounds from the Ny and OxNy classes. Higher pyrolysis temperatures resulted in more oxygenated phenolics (O4-7) undergoing secondary degradation and deoxygenation reactions, generating O2-3 compounds. Additional classes affected were O3-5N2-3, while O1-2N1 presented more stable compounds. These findings show that cassava bio-oils are promising sources of renewable chemicals.

Assuntos

RESUMO

Cassava (Manihot esculenta Crantz) is a staple crop widely cultivated by small farmers in tropical countries. However, despite the low level of technology required for its management, it can be affected by several diseases, with anthracnose as the main threat. There is little information about the main species of Colletotrichum that infect cassava in Brazil. Thus, the objective of this work was to study the diversity, prevalence and virulence of Colletotrichum species that cause anthracnose in cassava leaves in northern Brazil. Twenty municipalities of the Pará and Tocantins states were selected, and leaves with symptoms were collected in those locations. Pure cultures were isolated in the laboratory. Species were identified using phylogenetic analyses of multiple loci, and their pathogenicity, aggressivity and virulence levels were assessed. Our results showed the greatest diversity of Colletotrichum associated with anthracnose in cassava plants of the "Formosa" cultivar in the Tocantins and Pará states. We determined the presence of Colletotrichum chrysophilum, C. truncatum, C. siamense, C. fructicola, C. plurivorum, C. musicola and C. karsti, with C. chrysophilum as the most aggressive and virulent. Our findings provide accurate identifications of species of Colletotrichum causing anthracnose in cassava crops, which are of great relevance for cassava breeding programs (e.g., the search for genotypes with polygenic resistance since the pathogen is so diverse) and for developing anthracnose management strategies that can work efficiently against species complexes of Colletotrichum.

RESUMO

Cassava root-rot incited by soil-borne pathogens is one of the major diseases that reduces root yield. Although the use of resistant cultivars is the most effective method of management, the genetic basis for root-rot resistance remains poorly understood. Therefore, our work analyzed the transcriptome of two contrasting genotypes (BRS Kiriris/resistant and BGM-1345/susceptible) using RNA-Seq to understand the molecular response and identify candidate genes for resistance. Cassava seedlings (resistant and susceptible to root-rot) were both planted in infested and sterilized soil and samples from Initial-time and Final-time periods, pooled. Two controls were used: (i) seedlings collected before planting in infested soil (absolute control) and, (ii) plants grown in sterilized soil (mock treatments). For the differentially expressed genes (DEGs) analysis 23.912 were expressed in the resistant genotype, where 10.307 were differentially expressed in the control treatment, 15 DEGs in the Initial Time-period and 366 DEGs in the Final Time-period. Eighteen candidate genes from the resistant genotype were related to plant defense, such as the MLP-like protein 31 and the peroxidase A2-like gene. This is the first model of resistance at the transcriptional level proposed for the cassava × root-rot pathosystem. Gene validation will contribute to screening for resistance of germplasm, segregating populations and/or use in gene editing in the pursuit to develop most promising cassava clones with resistance to root-rot.

Assuntos

RESUMO

Despite fungal diseases affecting the aerial parts of cassava (Manihot esculenta Crantz) and causing significant yield losses, there is a lack of comprehensive studies assessing resistance in the species' germplasm. This study aimed to evaluate the phenotypic diversity for resistance to anthracnose disease (CAD), blight leaf spot (BliLS), brown leaf spot (BLS), and white leaf spot (WLS) in cassava germplasm and to identify genotypes suitable for breeding purposes. A total of 837 genotypes were evaluated under field conditions across two production cycles (2021 and 2022). Artificial inoculations were carried out in the field, and data on yield and disease severity were collected using a standardized rating scale. The top 25 cassava genotypes were selected based on a selection index for disease resistance and agronomic traits. High environmental variability resulted in low heritabilities (h2) for CAD, WLS, and BLS (h2 = 0.42, 0.34, 0.29, respectively) and moderate heritability for BliLS (h2 = 0.51). While the range of data for disease resistance was narrow, it was considerably wider for yield traits. Cluster analysis revealed that increased yield traits and disease severity were associated with higher scores of the first and second discriminant functions, respectively. Thus, most clusters comprised genotypes with hybrid characteristics for both traits. Overall, there was a strong correlation among aerial diseases, particularly between BLS and BliLS (r = 0.96), while the correlation between CAD and other diseases ranged from r = 0.53 to 0.58. Yield traits showed no significant correlations with disease resistance. Although the mean selection differential for disease resistance was modest (between -2.31% and -3.61%), selection based on yield traits showed promising results, particularly for fresh root yield (82%), dry root yield (39%), shoot yield (49%), and plant vigor (26%). This study contributes to enhancing genetic gains for resistance to major aerial part diseases and improving yield traits in cassava breeding programs.

RESUMO

OBJECTIVE: Determine the electrophoretic profiles of the extracts of Manihot esculenta, Actinidia Deliciosa and Persea Americana and their possible relationship with Latex-Fruit Syndrome. METHODS: Protein extracts of M. esculenta, P. Americana and A. Deliciosa were prepared through the processes of maceration and solvent extraction from plant samples. In the case of the avocado, a prior extraction by soxhlet was carried out to eliminate the fat. The extracts were vacuum filtered, dialyzed and finally lyophilized. Separation of proteins based on molecular weight was performed by SDS PAGE electrophoresis. The electrophoretic profiles obtained were compared with the allergenic proteins previously identified in the latex extract, in order to determine a possible relationship with Latex-Fruit Syndrome, depending on the molecular weight. RESULTS: The extracts of M. esculenta and P. Americana showed a wide range of protein fractions with molecular weights varying from 10 to 250 KD, finding that the region with the highest concentration of bands was between 20 and 89 KD, (60 and 65%), respectively. A 20-band profile was obtained for the M. esculenta extract (Figure 1), with seven bands sharing similar weights with the latex allergens (Hev b 1, Hev b 2, Hev b3, Hev b 4, Hev b 5, Hev b 6.03, Hev b 8 and Hev b 10) (3-5). For the P. Americana extract, 20 bands were also observed (Figure 2), seven of which presented approximate weights to the Latex allergens (Hev b 1, Hev b 2 Hev b 4 Hev b 6.01 Hev b 6.03 Hev b 8 , Hev b 10 Hev b 11 Hev b 14). The Kiwi extract showed two bands of 19.1 and 22.9 KD, with weights close to latex proteins (figure 3), (Hev b 3 and Hev b 6.01), and allergens (Act d 2 and Act d 6), reported in the literature for this fruit. CONCLUSIONS: When analyzing the relationship between the separated protein fractions and the latex allergens described in the literature, a possible association of 35% was found for the extracts of M. esculenta and P. Americana, and 10% for A. Delicious, with great relevance being the association found with the allergens Hev b 4, Hev b 2, Hev 8 and Hev b 11, which are involved in Latex-Fruit Syndrome. The electrophoretic profiles of the prepared extracts were determined and compared with the Latex allergens. This information generates a contribution for the development of new research and advances in the standardization of these extracts on a large scale and for their future use in diagnostic tests.

OBJETIVO: Determinar los perfiles electroforéticos de los extractos de Manihot esculenta, Actinidia deliciosa y Persea americana y su posible relación con el Síndrome de Látex ­ Fruta. MÉTODOS: Se prepararon extractos proteicos de M. esculenta, P. Americana y A. Deliciosa, a través de los procesos de macerado y extracción con solventes a partir muestras vegetales. En el caso del aguacate, se realizó una extracción previa por soxhlet, para eliminar la grasa. Los extractos se filtraron al vacío, se sometieron a diálisis y por último se liofilizaron. La separación de las proteínas en función del peso molecular se realizó mediante electroforesis SDS PAGE. Se compararon los perfiles electroforéticos obtenidos con las proteínas alergénicas previamente identificadas en el extracto de látex, con el fin de determinar una posible relación con el Síndrome de Látex-Fruta, en función del peso molecular. RESULTADOS: Los extractos de M. esculenta y P. americana mostraron una amplia gama de fracciones proteicas con pesos moleculares que varían desde 10 a 250 KD, encontrando que la región con mayor concentración de bandas se situó entre 20 y 89 KD, (60 y 65 %), respectivamente. Se obtuvo un perfil de 20 bandas para el extracto de M. esculenta (figura 1), con siete bandas que comparten pesos similares con los alérgenos del látex (Hev b 1, Hev b 2, Hev b3, Hev b 4, Hev b 5, Hev b 6.03, Hev b 8 y Hev b 10) (3-5). Para el extracto de P. americana, también se observaron 20 bandas (figura 2), siete de las cuales presentaron pesos aproximados a los alérgenos de Látex (Hev b 1, Hev b 2 Hev b 4 Hev b 6.01 Hev b 6.03 Hev b 8, Hev b 10 Hev b 11 Hev b 14). El extracto de Kiwi mostró dos bandas de 19,1 y 22,9 KD, con pesos cercanos a proteínas de látex (figura 3), (Hev b 3 y Hev b 6.01), y los alérgenos (Act d 2 y Act d 6), reportados en la literatura para esta fruta. CONCLUSIONES: Al analizar la relación existente entre las fracciones proteicas separadas y los alérgenos de los látex descritos en la literatura, se encontró una posible asociación del 35% para los extractos de M. esculenta y P. Americana, y del 10% para A. Deliciosa, siendo de gran relevancia la asociación encontrada con los alérgenos Hev b 4, Hev b 2, Hev 8 y Hev b 11, los cuales se encuentran implicados en el Síndrome de Látex-Fruto. Se lograron determinar los perfiles electroforéticos de los extractos elaborados y se compararon con los alérgenos del Látex. Está información genera un aporte para el desarrollo de nuevas investigaciones y avances en la estandarización de estos extractos a gran escala y para su uso futuro en pruebas diagnósticas.

Assuntos

RESUMO

The current study evaluated the effects of supplementing cassava root silage (CRS) to dairy cows grazing on Megathyrsus maximus cv Mombasa on nutrient intake and digestibility, as well as on milk production and composition. Ten primiparous Girolando cows with average body weight ± (SEM) of 373.45 ± (63.55) kg were used in a replicated 5 × 5 Latin square. Animals were subjected to five treatments: (I) grazing cows without supplementation (WCS); (II) grazing cows provided with 5 kg DM of supplement without CRS (0 g/kg DM of CRS) or including (III) 260, (IV) 520, and (V) 780 g/kg DM of CRS. Statistical analyses were performed using the PROC MIXED of SAS with significance at P < 0.05. Intake of neutral detergent fiber (NDF) and ether extract decreased (P < 0.01), while intake of non-fiber carbohydrates increased (P < 0.01), with increased CRS in the diets. Total DM intake and digestibility of DM, and digestibility of nutritional components were lower (P < 0.03) in WCS animals compared to supplemented animals, except for intake and digestibility of NDF, which was the opposite. Milk yield (MY) and fat corrected milk (FCM), as well as all milk components were unaffected (P > 0.05) by CRS inclusion. In contrast, MY, FCM, protein, lactose, casein, and non-fat milk solids (NFMS) were greater for animals that received supplementation (P < 0.05), compared to animals WCS. Milk fat and total dry extract (TMS) did not differ (P > 0.11) between two groups. In conclusion, CRS may be a potential corn meal replacer in the supplement of dairy cows under tropical conditions.

Assuntos

RESUMO

Background: Food allergy has considerably increased in recent years and this situation has been aggravated mainly by the consumption of more processed and complex foods, since minor or potentially allergenic foods are not required to be labeled. Manihot esculenta (cassava) is a widely consumed food in South America, Africa, and Asia and can be used in the production of flour and starch, as well as several other products. This root can cause allergic reactions with symptoms ranging from mild to severe. Methods: Thus, the aim of this study was the characterization of the immunogenic cassava proteins responsible for sensitizing patients allergic to it. Using a 2D-SDS-PAGE based proteomic approach, six proteins were identified, including Fructose Bisphosphate Aldolase (FBA). Recombinant FBA was produced in Expi293 cells and evaluated by immunoblotting with the serum of 10 individual study subjects. Results: Our results showed six cassava IgE-reactive proteins. From those, recombinant fructose bisphosphate aldolase (FBA) showed a positivity of 80% among tested sera, proving to be a highly sensitizing protein. Conclusion: The recombinant FBA molecule obtained in this study can be important for in vivo diagnostic assays, by producing more accurate results, and for desensitization protocols, in which the use of the isolated molecule produces more precise results by avoiding secondary sensitization. Trial registration: All patients signed a consent form approved by the internal ethics committee CAPPesq, Comissão de Ética para Análise de Projetos de Pesquisa do HC FMUSP (CAAE: 10420619.6.0000.0068).