Genetic control of resistance to Meloidogyne incognita race 1 in the Brazilian common bean (Phaseolus vulgaris L.) cv. Aporé

The use of resistant cultivars is one of the best methods for nematode control and reduction of economic losses caused by these pathogens. Studies of inheritance of nematode resistance in common bean (Phaseolus vulgaris L.) are nonetheless scarce. The present paper reports on the estimation of genetic parameters associated with resistance to the root nematode Meloidogyne incognita race 1 in common beans. Two contrasting bean lines, ‘Aporé’ (P₁ = nematode resistant) e ‘Macarr?o Rasteiro Conquista’ (P₂ = susceptible), and the generations F₁ (P₁ × P₂), F₂ (P₁ × P₂), BC₁(P₁) = (F₁ × P₁) and BC₁(P₂) = (F₁ × P₂), were assessed 45 days after nematode inoculation, through a scale related to the number of eggs per gram of root tissue. Dominant genetic effects were inferior in magnitude to additive effects, indicating incomplete dominance of nematode resistance. Dominance was in the direction of increased nematode resistance (i.e., lower number of eggs per g root). Resistance to Meloidogyne incognita race 1 in common bean is under control of a single gene locus, with incomplete dominance of the resistance allele present in ‘Aporé’, but modifier genes affecting its expression appear to be present in the susceptible parent ‘Macarr?o Rasteiro Conquista’.     

Strategies of supplementation of female suckling calves and nutrition parameters of beef cows on tropical pasture

The performance of female calves in creep feeding under different strategies of supplementation and milk production, intake, and digestibility of grazing Nellore and crossbred cows (Nellore?×?Holstein) during the dry-rainy transition season were assessed. Forty-four female beef suckling calves, with initial age between 90 and 150?days and average initial body weight of 117.7?±?4.3?kg, and their respective dams (24 Nellore and 20 crossbred) with average initial body weight of 417.5?±?8.3?kg, were used. The experimental treatments consisted of: control group-mineral mixture only; strategy 1-supplementation from 112?days prior to weaning (0.375?kg/animal/day); strategy 2-supplementation from 112?days prior to weaning, in increasing amounts of 0.15, 0.30, 0.45, and 0.60?kg/animal/day through the four experimental periods, respectively; and strategy 3-supplementation from 56?days prior to weaning (0.750?kg/animal/day). Calves from strategy 1 had greater (P??0.05) for nutrient digestibility among genetic types. It can be concluded that strategies of supplementation that present an equitable distribution of supplement provides greater weight gain in suckling female beef calves. Crossbred cows produce more milk and present greater DMI than Nellore cows. There are no differences in the nutrient digestibility between Nellore and Nellore × Holstein crossbred cows.     

Efficiency of resistance elicitors in the management of grapevine downy mildew Plasmopara viticola: epidemiological, biochemical and economic aspects

This paper aimed to evaluate the efficiency of resistance elicitors in the management of grapevine downy mildew (Plasmopara viticola), identify the action of the elicitors on host metabolism, and determine their economic viability. The experiments were performed in a commercial vineyard variety ‘Isabel’ (Vitis labrusca) at Vale do Sirijí [Natuba, Paraiba State in Brazil, in the period of September 2009 to January 2010 (first season) and February to June 2010 (second season)]. The statistical design of randomized blocks consisted of eight treatments (untreated control, fungicide (pyraclostrobin+metiram), potassium phosphite, Agro-Mos?, Fungicide+potassium phosphite, Fungicide+Agro-Mos?, potassium phosphite+AgroMós? and Fungicide+potassium phosphite+Agro-Mos?) with four replications, with the experimental unit consisting of 45 leaves. Applications were made every 7?days, starting 20?days after pruning (DAP) with a total of 12 sprays. The evaluations were carried out biweekly, analyzing the following variables: incubation period, disease incidence and severity, area under the disease progress curve, and efficiency of control. The enzymatic determination was performed using pulp extracts from three fruits harvested at 45, 60, 90 and 120 DAP for each treatment. The resistance elicitors were able to reduce the disease incidence under different climatic conditions, indicating their viability as an alternative for the management of Plasmopara viticola.     

Production and characterization of recombinant transmembrane proteins from Mycoplasma hyopneumoniae

Mycoplasma hyopneumoniae is the etiological agent of swine enzootic pneumonia (EP), a chronic respiratory disease which causes significant economic losses to the swine industry worldwide. More efficient strategies for controlling this disease are necessary. In this study, we cloned17 genes coding for transmembrane proteins from M. hyopneumoniae, among which six were successfully expressed in Escherichia coli and had their immunogenic and antigenic properties evaluated. All proteins were immunogenic in mice and sera from naturally infected pigs reacted with the recombinant proteins, suggesting that they are expressed during infection. These antigens may contribute for the development of new recombinant vaccines and diagnostic tests against EP.     

Post‐infection development and histopathology of Meloidogyne arenaria race 1 on Arachis spp.

The reproductive behaviour of the root‐knot nematode Meloidogyne arenaria race 1 was compared on two wild species of Arachis (A. duranensis and A. stenosperma) and cultivated peanut (A. hypogaea cv. IAC‐Tatu‐ST). The three species were considered moderately susceptible, resistant, and susceptible, respectively. Penetration and development of the root‐knot nematode in the resistant species was reduced in comparison with that occurring in susceptible plants. Several cell features, including dark blue cytoplasm and altered organelle structure were observed in the central cylinder of A. stenosperma, indicating a hypersensitive‐like response (HR) of infested host cells. Neither giant cells, nor nematodes developed beyond the second stage, were found on A. stenosperma. Arachis duranensis showed a delay in the development of nematodes in the roots compared to A. hypogaea. The two wild peanut species were chosen to be the contrasting parents of a segregating population for mapping and further investigation of resistance genes.     

Cassava (<Emphasis Type="Italic">Manihot esculenta</Emphasis> Crantz) genetic resources: a case of high iron and zinc

Cassava hybrids from interspecific crosses with Manihot caerulescens Pohl, M. pseudoglaziovii Pax and Hoffmann and M. dichotoma Ule showed a very high iron and zinc content in both roots and leaves, e.g. 98.15 mg kg⁻¹ in roots of the interspecific hybrid cassava-M. caerulescens versus 12.17 mg kg⁻¹ in a cassava cultivar. This promising results show the potential of wild Manihot species for micronutrient enhancement of cassava.     

Evaluation of changes in microbiota after fecal microbiota transplantation in 6 diarrheic horses

The purpose of this study was to characterize the fecal microbiota of horses with acute and chronic diarrhea before and after fecal microbiota transplantation (FMT). Six client-owned horses with acute and chronic diarrhea received FMT from 2 healthy donor horses. Microbiota analysis using next-generation sequencing was performed on fecal samples collected before and 2 and 7 d after FMT. Signs of diarrhea improved in 4 horses, whereas the remaining 2 horses did not survive. There was a significant difference in the number of bacterial species between donors and recipients (P < 0.05). The Order Lactobacillales and the genera Lactobacillus, Intestinimonas, and Streptococcus were increased in the microbiota of diarrheic horses, and Saccharofermentans genus increased in healthy donors. The results suggest that FMT from the healthy donors was not effective over a 7-day period as it did not change the fecal microbiota of the diarrheic horses. Further research to improve the efficacy of FMT in horses is needed.     

Use of Spray-Dried Blood Meal as an Alternative Protein Source in Pirarucu (Arapaima gigas) Diets

We evaluated the effects of various dietary blood meal levels on the growth performance and body composition of pirarucu (Araipama gigas) juveniles. Fish (8.5 ± 0.4 g) were stocked into 24 tanks and fed for 60 days with eight isoproteic diets, having 0% to 21% incorporation of blood meal. Fish increased weight by six to 15 times from their initial weight. The highest body weights (117–135 g), growth rates (4%–5% BW/day), and protein retentions (19%–20%) were observed in fish fed 0% to 6% blood meal. Feed intake increased from 2.9% to 4.4% BW/day with increasing blood meal level. Feed conversion ratio (FCR: 1.0–1.1) did not vary among groups fed 0% to 6% blood meal (P < 0.001). However, when fish were fed more than 6% blood meal, FCR (1.3–1.7) and protein retention (11.1–13.7) deteriorated sharply. Lipid (7.7–11.7%) and energy (18.7–21.2 kJ/g) content increased with increasing blood meal levels up to 9%.     

Ultrasonography Criteria for Differentiating ACTH Dependency from ACTH Independency in 47 Dogs with Hyperadrenocorticism and Equivocal Adrenal Asymmetry

Background: Adrenal ultrasonography (US) in dogs with hyperadrenocorticism (HAC) is commonly used to distinguish adrenocorticotropic hormone (ACTH)‐independent (AIHAC) and ACTH‐dependent hyperadrenocorticism (ADHAC). To date, no cut‐off values for defining adrenal atrophy in cases of adrenal asymmetry have been determined. Given that asymmetrical hyperplasia is sometimes observed in ADHAC, adrenal asymmetry without ultrasonographic proof of adrenocortical tumor such as vascular invasion or metastasis can be equivocal. Objective: The purpose of this study was to compare adrenal US findings between cases of ADHAC and AIHAC in dogs with equivocal adrenal asymmetry (EAA), and to identify useful criteria for their distinction. Animals: Forty dogs with EAA were included. Methods: Ultrasound reports of HAC dogs with adrenal asymmetry without obvious vascular invasion or metastases were reviewed. Dogs were classified as cases of ADHAC (n = 28) or AIHAC (n = 19), determined by plasma ACTH concentration. The thickness, shape, and echogenicity of both adrenal glands and presence of adjacent vascular compression were compared between AIHAC and ADHAC groups. Results: The maximal dorsoventral thickness of the smaller gland (SDV) ranged from 2.0 to 5.0 mm in AIHAC and from 5.0 to 15.0 mm in ADHAC. The 95% confidence intervals for estimated sensitivity and specificity of a SDV cut‐off set at 5.0 mm in the diagnosis of AIHAC were 82–100 and 82–99%, respectively. Other tested US criteria were found to overlap extensively between the 2 groups, precluding their usefulness for distinction. Conclusion and Clinical Importance: In EAA cases, an SDV ≤5.0 mm is an appropriate cut‐off for AIHAC ultrasonographic diagnosis.     

The effects of <Emphasis Type="Italic">Gibberella zeae</Emphasis>, <Emphasis Type="Italic">Barley Yellow Dwarf Virus</Emphasis>, and co-infection on <Emphasis Type="Italic">Rhopalosiphum padi</Emphasis> olfactory preference and performance

Insect-borne viruses promote several changes in plant phenotype, which can modify plant-vector interactions in favor of virus survival and dissemination. Although co-infections commonly occur in the field, little is known about their effects on interactions with the vector. The ecological interactions between Barley Yellow Dwarf Virus (BYDV) and its aphid vector, Rhopalosiphum padi, have been investigated extensively, but the vector’s behavior in more complex scenarios has yet to be examined. We assessed olfactory response and performance of R. padi to wheat singly and doubly infected by the pathogenic fungus Giberella zeae and BYDV. Non-viruliferous aphids preferred odors of BYDV-infected wheat over healthy wheat, as previously reported in the literature, and they were still preferentially attracted to BYDV-infected plant during co-infection. However, around 35% more non-viruliferous aphids chose healthy wheat over G. zeae-infected wheat. Viruliferous aphids did not show any preference to the treatments. BYDV-infected wheat was a superior host than healthy wheat for the aphids whose population increased in 25%. We observed a synergistic effect of the co-infected wheat, which was the best host for aphids, and promoted an elevation of 42% on population growth. Our results indicate that co-infection might be beneficial for virus spread as does not interfere with aphid olfactory preference and provides greater colony growth than in singly infected plants.