Search Results (275)

Rhipicephalus microplus is an important biological vector as it transmits several pathogens, including Babesia bovis, the causative agent of bovine babesiosis. The available strategies for controlling B. bovis are limited, resulting in substantial challenges for both animal health and livestock management. Infection of the tick midgut is the essential first step for the transmission cycle of B. bovis, yet this process remains largely unexamined. To better understand the first step of tick infection, this study employed a proteomic approach to identify a midgut protein that responds to B. bovis infection. We then used RNA interference for gene silencing to determine if the protein is essential for R. microplus infection. The protein we identified, Rm24, is twofold upregulated in the tick midgut during B. bovis infection. We silenced the gene encoding Rm24 and examined the effect of reduced expression on both tick fitness and B. bovis infection. Our results indicated that silencing the Rm24 gene impacted the survivability of adult female ticks, which exhibited a significant reduction in viability as compared to the control and non-injected groups. Importantly, we found that suppressing the gene encoding Rm24 led to a significant decrease in the number of engorged female ticks infected, with only 15% of female ticks testing positive for B. bovis kinetes as compared to over 50% in the control groups. We also detected a significant reduction in vertical transmission of B. bovis to larval progenies. These findings suggest that the Rm24 protein is critical for infection by B. bovis and could serve as a promising target for future transmission-blocking strategies. Full article

The current work focused on the molecular selection of Oreochromis niloticus with improved growth performance through marker-trait associations between SNPs within the growth hormone gene (GH) and growth performance. A total of 155 fish of the same age were collected from three locations (Lake Brullus (B), the River Nile at El-Qanater El-Khairia (Q), and Lake Nasser (A)). The selected individual progenies were evaluated through gene expression analysis for growth, inflammatory, nervous, and immune-related genes. A total of nine SNPs and three InDels were significantly associated with morphometric characteristics. The phenotypic variance (R²) of the detected SNPs ranged between 2.6% and 36%. The best populations were A and Q, as they recorded the best growth performance and harboured the highest number of SNPs and InDels, in addition to a significant increase in body weight and length. Furthermore, their progenies documented the most promising gene expression patterns of all tested genes. The current research highlights the importance of molecular selection and the potential use of population-specific SNPs in tilapia breeding programs. Full article

We report the development of a procedure for ultrasound-assisted microscale extraction of metabolites from the flowers of Saint John’s wort (Hypericum perforatum L.), designed for comparative metabolite analysis of plants from genetic resource collections and natural and segregating populations. The procedure involves high-throughput methanol extraction of metabolites from ground-frozen flowers at a selected stage of flower development, which is carried out in a standard 2 mL Eppendorf tube. A total of 18 compounds, including chlorogenic acid, catechins, glycosylated flavonoids, hypericins, and hyperforin, were identified based on LC/DAD/QTOF analysis, of which 16 could be detected in the UV-Vis spectrum. Two alternative versions of the procedure were evaluated: the “single-flower” procedure, including repeated collection and analysis of single flowers from the tested plant, and the “bulk-flower” procedure, employing the collection of a bulk flower sample from the tested plant and analysis of a portion of the ground sample. The results showed excellent technical reproducibility of the “single-flower” procedure when used with the suggested combination of the peak areas for the proto- and stable forms of pseudohypericin and hypericin. Application of the developed “single-flower” procedure for comparison of the plants derived from seed progeny of the apomictic line Hp93 revealed significantly lower metabolite variation among the apomictic progeny plants compared to the variation observed among plants belonging to different genotypes. Full article

Potato common scab is one of the major diseases posing a threat to potato production on a global scale. No chemical agents have been found to effectively control the occurrence of this disease, and research on the identification of resistance genes and the development of molecular markers remains relatively limited. In this study, a diploid potato variety H535, which exhibits resistance to the predominant pathogen Streptomyces scabies, was utilized as the male parent, whereas the susceptible diploid potato variety H012 served as the female parent. Building upon the resistance QTL intervals pinpointed through a genome-wide association study, two potential resistance loci were localized on chromosome 2 of the potato genome, spanning the regions between 38–38.6 Mb and 41.3–42.7 Mb. These intervals accounted for 18.03% of the total phenotypic variance and are presumed to be the primary QTLs underlying scab resistance. Building upon this foundation, we expanded the hybrid progeny population, conducted resistance assessments, selected individuals with extreme phenotypes, developed molecular markers, and conducted fine mapping of the resistance gene. A phenotypic evaluation of scab resistance was carried out using a pot-based inoculation test on 175 potato hybrid progenies to characterize the F1 generation population. Twenty lines exhibiting high resistance and thirty lines displaying high susceptibility were selected for investigations. Within the preliminary mapping interval on potato chromosome 2 (spanning 38–43 Mb), a total of 214 SSR (Simple Sequence Repeat) and 133 InDel (Insertion/Deletion) primer pairs were designed. Initial screening with parental lines identified 18 polymorphic markers (8 SSR and 10 InDel) that demonstrated stable segregation patterns. Validation using bulked segregant analysis revealed that 3 SSR markers (with 70–90% linkage) and 6 InDel markers (with 70–90% linkage) exhibited significant co-segregation with the resistance trait. A high-density genetic linkage map spanning 104.59 cm was constructed using 18 polymorphic markers, with an average marker spacing of 5.81 cm. Through linkage analysis, the resistance locus was precisely mapped to a 767 kb interval (41.33–42.09 Mb) on potato chromosome 2, flanked by SSR-2-9 and InDel-3-9. Within this refined interval, four candidate disease resistance genes were identified: RHC02H2G2507, RHC02H2G2515, PGSC0003DMG400030643, and PGSC0003DMG400030661. This study offers novel insights into the genetic architecture underlying scab resistance in potato. The high-resolution mapping results and characterized markers will facilitate marker-assisted selection (MAS) in disease resistance breeding programs, providing an efficient strategy for developing cultivars with enhanced resistance to Streptomyces scabies. Full article

Background/Objectives: To overcome the limitations imposed by bacterial blight on widely adopted indica–japonica hybrid rice, this study employed molecular design breeding strategies to develop a resistant germplasm. Methods: Through conventional backcross breeding combined with molecular-marker-assisted selection, the Xa23-carrying material XR39 was hybridized with the wide-compatibility restorer line R5315 harboring the S5n gene. Progeny selection integrated evaluations of agronomic traits, disease resistance identification, and test-crossing with sterile lines. Results: Five wide-compatibility restorer lines simultaneously incorporating the Xa23 and S5n genes were successfully developed, demonstrating outstanding bacterial blight resistance and restoration ability. The selected hybrid combinations, A3/RP1, A1/RP4, and A4/RP4, exhibited yield increases of 2.6–8.6% compared to the control. Conclusions: This study not only established a novel germplasm for developing bacterial blight-resistant indica–japonica hybrid rice varieties, but also established a model for gene design breeding for rice improvement. Full article

Background: Single-step genomic BLUP (ssGBLUP) has gained increasing interest from forest tree breeders. ssGBLUP combines phenotypic and pedigree data with marker data to enhance the prediction accuracy of estimated breeding values. However, potential errors in determining progeny relationships among open-pollinated species may result in lower accuracy of estimated breeding values. Unknown parent groups (UPG) and metafounders (MF) were developed to address missing pedigrees in a population. This study aimed to incorporate MF into ssGBLUP models to select the best parents for controlled mating and the best progenies for cloning in a tree breeding population of Eucalyptus globulus. Methods: Genetic groups were defined to include base individuals of similar genetic origin. Tree growth was measured as total height (TH) and diameter at breast height (DBH), while disease resistance was assessed through heteroblasty (the transition from juvenile to adult foliage: ADFO). All traits were evaluated at 14 and 21 months. Two genomic multi-trait threshold linear models were fitted, with and without MF. Also, two multi-trait threshold-linear models based on phenotypic and pedigree information (ABLUP) were used to evaluate the increase in accuracy when adding genomic information to the model. To test the quality of models by cross-validation, the linear regression method (LR) was used. Results: The LR statistics indicated that the ssGBLUP models without MF performed better, as the inclusion of MF increased the bias of predictions. The ssGBLUP accuracy for both validations ranged from 0.42 to 0.68. Conclusions: The best model to select parents for controlled matings and individuals for cloning is ssGBLUP without MF. Full article

Stored grain pests cause significant economic losses during cereal grain storage. Insecticides have long been central to pest control; however, growing concerns over resistance, environmental harm, and human health demand alternative strategies. Diatomaceous earth (DE) treatments are a safe, eco-friendly alternative to insecticides, although their efficacy depends on the temperature, humidity, dose, and insect species. This study assessed the insecticidal effects of two natively-sourced raw (Ankara and Aydin) and one commercial (Silico-Sec) DE treatments against the key pest species Rhyzopertha dominica (F.) and Sitophilus granarius (L.) on stored wheat. Five doses (0, 250, 500, 750, and 1000 ppm) of each DE treatment were tested under two temperatures (25 °C and 30 °C) and two humidity levels (40% and 60%). Mortality was assessed at 7, 14, and 21 days after treatment (DAT). All DE treatments caused higher mortality in S. granarius than R. dominica. The highest mortality occurred in S. granarius at 30 °C and 40% RH with the highest dose. Aydin DE was most effective, but did not reach 100% mortality in S. granarius by 21 DAT. In contrast, it caused 100% mortality in R. dominica under the same conditions. There was no F₁ progeny produced by surviving individuals of both species. Given the similarity of the environmental conditions to the optimal conditions for DE efficacy present in Turkish storage facilities, natively sourced Aydin DE is a promising control option. Full article

Diclofenac, a nonsteroidal anti-inflammatory drug widely used worldwide, has been detected in waterbodies at concentrations ranging from ng L⁻¹ to µg L⁻¹. Although diclofenac is not a persistent compound, aquatic organisms may be exposed to this drug for extended periods due to its incorporation into the environment by continuous release from hospitals and municipal discharges. This study aimed to evaluate the toxic effects of diclofenac on the microalga Pseudokirchneriella subcapitata, the cladoceran Daphnia curvirostris, and zebrafish embryos (Danio rerio). Toxicity bioassays for the microalga were performed according to the OECD 201 protocol with diclofenac concentrations of 0, 6.25, 12.5, 25, 50, 75, and 100 mg L⁻¹. For the determination of acute toxicity in the cladoceran (48 h), concentrations of 0, 10, 20, 30, 40, 50, and 60 mg L⁻¹ were tested; in subchronic bioassays, the effect of the drug on the reproductive parameters of D. curvirostris was determined for 21 days with sublethal concentrations of 10.3, 14.4, 17.2, and 21.3 mg L⁻¹. Toxicity bioassays on zebrafish embryos were performed according to the OECD 236 protocol, using concentrations of 0, 1, 2, 4, 6, 8, and 10 mg L⁻¹ of diclofenac. The results confirmed the toxic effects of the drug. The IC₅₀ for the microalga was 16.57 mg L⁻¹, while the LC₅₀ for D. curvirostris and D. rerio was 32.29 and 6.27 mg L⁻¹, respectively. In the microalga, chlorophyll-a and carotenoids increased at a concentration of 3.62 mg L⁻¹ of diclofenac; however, chlorophyll-b decreased at the highest drug concentration (13.51 mg L⁻¹). Protein and lipid concentrations in P. subcapitata exposed to all concentrations were higher than in the control. Chronic diclofenac exposure did not affect the survival of D. curvirostris; however, the cumulative progeny and number of clutches significantly decreased, and the age of first reproduction was delayed at all drug concentrations. Protein concentration in D. curvirostris hatchlings was higher at all diclofenac concentrations; in contrast, the amount of lipids and carbohydrates decreased significantly. In D. rerio, the hatching rate decreased by 40, 51.6, and 80% at concentrations of 6, 8, and 10 mg L⁻¹ diclofenac, respectively, and exposure to the drug caused lethal effects such as coagulation at 24 and 48 hpf; sublethal effects such as edema and curved tail were also observed at concentrations of 2 to 10 mg L⁻¹, and the effects increased with increasing concentration up to 144 hpf. The results demonstrate the vulnerability of aquatic organisms to the toxic effects of diclofenac, suggesting that discharging it into water bodies should be regulated to prevent potential ecological impacts on the various trophic levels of freshwater biota. Full article

Damage to the photosynthetic apparatus during leaf dehydration is an indicator of the maintenance of leaf vitality and the resilience of tree seedlings to severe drought. Genipa americana is a tree widely distributed in the neotropical region but with great ecological and sociocultural importance in the south of the state of Bahia, Brazil, where its fruits are harvested from subspontaneous trees. This study aimed to compare the feasibility of the maximum quantum efficiency of photosystem II (Fv/Fm) and performance indexes derived from the JIP test, i.e., performance index on absorption basis (PI_abs) and total performance index (PI_total), for screening G. americana seedlings from different mother plants for leaf damage caused by dehydration. From leaf dehydration curves, we calculated the values of relative water content (RWC) in which Fv/Fm, PI_abs, and PI_total reach a loss of 10% and 50% in relation to the values of fully hydrated leaves. PI_total was the only parameter that revealed consistent significant differences between progenies for RWC at 50% of percentage loss. Significant differences were observed among progenies for leaf traits; however, no correlation was detected between these traits and chlorophyll fluorescence parameters. Monitoring the PI_total values during leaf dehydration is a useful tool for screening G. americana progenies in relation to their capacity to maintain leaf vitality under occasional severe droughts. Full article

Traditional quantitative genetic models in forestry often overlook the influence of an individual’s genes on neighboring trees. However, genetic competition models help bridge this gap. Competition varies among populations, over time, and across environments, yet forest breeders rarely monitor these dynamics or their effects on selected genotypes. We investigated the effects of competition on genetic variances, breeding value accuracy, and selection response in 14 Pinus taeda L. progeny tests using spatial (Spa) and spatial-competition (Spa-Comp) individual-tree mixed models. Our analysis covered traits such as diameter at breast height (DBH), total height (TH), and stem straightness (STR) across ages (3–21 years) and sites (altitude, soil texture, drainage). DBH was more affected by genetic competition than TH and STR, with effects varying across ages and sites. Direct-competition genetic correlations were negative for DBH from age 5 onward but positive for TH, reducing total heritable variance for DBH (<43.1%) while increasing for TH (<95.7%). Genetic competition accounted for less than 26% of direct additive variance. For DBH, the Spa-Comp model slightly improved breeding value accuracy (<~4%), while Spa inflated selection response (<3.83 percentage points), yet rank changes were minimal (common selected trees > 89%). These findings indicate that while competition inflates genetic gains, its impact on selection efficiency is minimal. Full article

With over 1000 species of pests causing losses in both the quantity and quality of stored food, insect contamination poses significant challenges. The present study assesses the efficacy of the combination of λ-cyhalothrin and chlorantraniliprole against four key storage pests—Trogoderma granarium, Sitophilus oryzae, Rhyzopertha dominica, and Tribolium castaneum. Laboratory bioassays demonstrated species-dependent mortality, with S. oryzae and R. dominica suffering 100% mortality in several tested scenarios. A 90-day persistence trial revealed decreased efficacy over time, especially for T. granarium (32.0–71.4% at 0 days and 0.0–7.5% at 90 days) and T. castaneum (38.8–82.7% at 0 days and 0.0–12.7% at 90 days) vs. S. oryzae and R. dominica. Progeny production of S. oryzae and R. dominica was almost suppressed in persistence trials (0.4 individuals per vial and 1 individual per vial, respectively) after 30 days of storage at the dose of 5 mg/kg wheat. The results highlight the variability in insecticidal performance based on species, dose, exposure, and commodity type, emphasizing the need for tailored pest management strategies in the storage environment. Full article

Different inert materials have been tested as grain protectants against stored-product mites with variable results. Most of the studies are focused on the efficacy of diatomaceous earth, but there are few comparable data on other types of inert dust. In this study, we have tested two inert materials, zeolite and kaolin, against the cheese mite Tyrophagus putrescentiae (Schrank) (Astigmata: Acaridae) on wheat. Mites were reared in the laboratory under controlled conditions of 25 °C and 80% relative humidity. Bioassays were conducted to assess the acaricidal effects of zeolite and kaolin. These formulations were applied to wheat kernels at 100, 500, and 1000 ppm. The treated wheat was manually mixed and divided into 1 g subsamples, each containing ten T. putrescentiae. Mortality was recorded after 3 and 7 days, while progeny production was assessed after 42 days. Control samples without treatment were also included, and all experiments were conducted under the same controlled conditions. Our results indicated that zeolite was more effective than kaolin, regardless of the dose rates tested. Parental mortality reached 100% on wheat treated with 1000 ppm of zeolite after only 3 days of exposure. In contrast, survival of T. putrescentiae was noted in all doses of kaolin. Moreover, progeny production in the treated substrate was not avoided even in the highest dose of kaolin but was totally (100%) suppressed at 500 and 1000 ppm. Our results illustrate that zeolite was very effective for the control of this species, even at short exposure intervals, and hence, can be considered further as a grain protectant. Full article

Rhizomes, key carbon sequestration sinks in perennial crops, are hypothesized to exhibit a trade-off with grain yield. This study evaluated rhizomatous grain sorghum populations for increasing carbon sequestration potential. Twelve F_3:4 heterogeneous inbred families (HIFs) from a Sorghum bicolor (L.) Moench × Sorghum propinquum (Kunth) Hitchc cross were tested in a greenhouse, and two F_4:5 HIF progenies were field tested. Traits measured included rhizome biomass, root biomass, total belowground biomass, and grain yield. Rhizome biomass showed high heritability (0.723) and correlated strongly with belowground biomass (r₁ = 0.95; r₂ = 0.97) in both F_4:5 HIFs, suggesting the potential of rhizomes to sequester carbon. Contrary to the hypothesized trade-off, a positive relationship between rhizome biomass and grain yield was observed, potentially via rhizome-derived shoots, and individual plants pyramiding high rhizome biomass, biomass yield, and grain yield were also identified. Using bulked segregant analysis (BSA), twenty simple sequence repeat (SSR) markers linked to eight genomic regions associated with rhizome presence were identified, with five regions potentially being novel. This study suggests that breeding rhizomatous grain sorghum with high rhizome biomass could enhance carbon sequestration while preserving agronomic yields, offering new insights for future breeding and mapping initiatives. Full article

The Severe Acute Respiratory Syndrome-related Coronavirus 2 (SARS-CoV-2), a causative agent of the COVID-19 disease, has been constantly evolving since its first identification. Mutations that are embedded in the viral genomic RNA affect the properties of the virus and lead to the emergence of new variants. During the COVID-19 pandemic, the World Health Organization has identified more than ten variants of the SARS-CoV-2 virus. Five of these—Alpha, Beta, Gamma, Delta, and Omicron—were classified as variants of concern (VOCs), as they caused significant outbreaks of the disease. Additionally, two progeny variants of Omicron, designated JN.1 and KS.1, are still causing new waves of infections. Due to the emergence of various SARS-CoV-2 variants, in some cases, it has become important to identify a particular variant in a sample. Here, we have developed a multiplexed probe-based real-time PCR system for the identification of SARS-CoV-2 VOCs (Alpha, Beta, Gamma, Delta, Omicron B.1.1.529/BA.1, and Omicron BA.2), as well as modern Omicron variants JN.1 and KS.1. The sensitivity and specificity of the PCR system have been tested using isolated viral genomes and RNA preparations from human nasopharyngeal swabs. The system allows for rapid identification of coronavirus variants in the cryopreserved and fresh samples. Full article

Cassava brown streak disease (CBSD) remains the most severe threat to cassava production in the Great Lakes region and Southern Africa. Screening for virus resistance by subjecting cassava to high virus pressure in the epidemic zone (hotspots) is a common but lengthy process because of unpredictable and erratic virus infections requiring multiple seasons for disease evaluation. This study investigated the feasibility of graft-infections to provide a highly controlled infection process that is robust and reproducible to select and eliminate susceptible cassava at the early stages and to predict the resistance of adapted and economically valuable varieties. To achieve this, a collection of cassava germplasm from the Democratic Republic of Congo and a different set of breeding trials comprising two seed nurseries and one preliminary yield trial were established. The cassava varieties OBAMA and NAROCASS 1 infected with CBSD were planted one month after establishment of the main trials in a 50 m² plot to serve as the source of the infection and to provide scions to graft approximately 1 ha. Grafted plants were inspected for virus symptoms and additionally tested by RT-qPCR for sensitive detection of the viruses. The incidence and severity of CBSD and cassava mosaic disease (CMD) symptoms were scored at different stages of plant growth and fresh root yield determined at harvesting. The results from the field experiments proved that graft-infection with infected plants showed rapid symptom development in susceptible cassava plants allowing instant exclusion of those lines from the next breeding cycle. High heritability, with values ranging from 0.63 to 0.97, was further recorded for leaf and root symptoms, respectively. Indeed, only a few cassava progenies were selected while clones DSC260 and two species of M. glaziovii (Glaziovii20210005 and Glaziovii20210006) showed resistance to CBSD. Taken together, grafting scions from infected cassava is a highly efficient and cost-effective method to infect cassava with CBSD even under rugged field conditions. It replaces an erratic infection process with a controlled method to ensure precise screening and selection for virus resistance. The clones identified as resistant could serve as elite donors for introgression, facilitating the transfer of resistance to CBSD. Full article