Epidemiology,histopathology and aetiology of olive anthracnose caused by Colletotrichum acutatum and C. gloeosporioides in Portugal

Anthracnose is an important disease affecting mature olive fruits, causing significant yield losses, and poor fruit and oil quality. In Portugal, high anthracnose incidence was recorded during 2003–2007 with 41% of 908 orchards surveyed displaying disease symptoms. In another 14% of the orchards, the pathogen was recorded in symptomless plants. Disease severity was on average 36%, frequently reaching 100%. In Portugal, anthracnose is endemic to neglected orchards of susceptible cultivars, but under favourable conditions it can also severely affect less susceptible cultivars. Pathogens were genetically heterogeneous, with Colletotrichum acutatum genetic group A2 as the most frequent (80%), followed by group A4 (12%) and group A5 along with C. gloeosporioides (3–4%), while groups A3 and A6 of C. acutatum were sporadic. Important geographic variations were observed in the frequencies of these populations, accompanied by year‐to‐year populational shifts. Epidemiology and histopathology studies showed the presence of the pathogens on vegetative organs year‐round, particularly on olive leaves and branches, and on weeds. These represent inoculum reservoirs where secondary conidiation occurs, and conidia are then dispersed by spring rains reaching flowers and young fruits or by autumn rains reaching pre‐mature fruits. Unripe fruits were colonized without showing symptoms up to penetration of the cuticle, but further colonization and symptom production was completed only as fruits matured. These findings challenge current control practices, particularly the timing of fungicide treatment, and contribute to improved disease management.     

Global population genetic structure of the sequential hermaphrodite,dusky grouper (Epinephelus marginatus)

1. The dusky grouper Epinephelus marginatus is a large epinephelid species that occurs in the eastern and south-western Atlantic and western Indian Oceans. Late maturity, protogynous hermaphroditism, site fidelity, and overfishing have all contributed to its demographic decline.
2. Connectivity and demography within a broad sampling of dusky grouper populations throughout its distribution were assessed. To do so, genetic variation at 11 polymorphic microsatellite loci and a partial sequence of the mitochondrial control region (mtCR) were evaluated.
3. Two major mtCR lineages with a sequence divergence of 1.6% were found. The magnitude of genetic differentiation for mtCR among north and south Atlantic and Indian Ocean populations was high, with Φ_ST = 0.528.
4. D_EST and results of discriminant analysis of principal component revealed significant microsatellite genetic differentiation between all collection areas. Significant pairwise D_EST showed moderate (0.084) to very great (0.603) differentiation. The effective population size was low for all localities, ranging between 25 (Azores Archipelago) and 311 (Rio Grande do Sul). The overall effective population size was estimated as 299 (confidence interval = 215–412), and there was no evidence of strong or recent bottleneck effects.
5. Local and regional genetic structuring among dusky grouper populations is the consequence of the species' site fidelity, distribution across multiple oceanographic boundaries, and probably also of sequential hermaphroditism that contributes to the intensity of random genetic drift.
6. The spatial pattern of genetic structuring of dusky groupers is such that fisheries management and conservation of population genetic integrity will have to be pursued at the local and regional scales.

     

Morphological and Genomic Differences Between Cutting and Racing Lines of Quarter Horses

To investigate morphological and genomic differences between cutting and racing lines of Quarter Horses, 120 racing and 68 cutting animals of both sexes, registered at the Brazilian Association of Quarter Horse Breeders, were used. Blood samples were collected, and the following physical traits were measured: weight; height at withers; body length; length of the shank, pastern, rump, head, and neck; and chest, shank, and hoof circumference. For analysis of genomic differences, 54,602 single-nucleotide polymorphisms (SNPs) were genotyped using the Equine SNP50 BeadChip, and the quality of individual and SNP genotype data were evaluated. The fixation index, F_ST, was used to identify genome regions that were altered in the lines by selection. The results showed significant differences between the lines in all physical traits. Quality control led to the exclusion of four cutting animals with a call rate of <0.95. After filtering, 12,544, 13,815, and 13,370 SNPs were excluded for the whole population (n = 184), the 120 racing animals, and the 64 cutting animals, respectively. The number of informative polymorphisms detected in each line and in the whole population indicated that the Equine SNP50 BeadChip can be used in genetic studies of Quarter Horses. The fixation index, F_ST, identified 2,558 genome regions that may have been modified by divergent selection.     

Biogeochemical Cycle of Mercury and Methylmercury in Two Highly Contaminated Areas of Tagus Estuary (Portugal)

Mercury (Hg) dynamics was evaluated in contaminated sediments and overlying waters from Tagus estuary, in two sites with different Hg anthropogenic sources: Cala Norte (CNOR) and Barreiro (BRR). Environmental factors affecting methylmercury (MMHg) production and Hg and MMHg fluxes across sediment/water interface were reported. [THg] and [MMHg] in solids (0.31–125 μg g^?1 and 0.76–201 ng g^?1, respectively) showed high variability with higher values in BRR. Porewater [MMHg] (0.1–63 ng L^?1, 0.5–86% of THg) varied local and seasonally; higher contents were observed in the summer campaign, thus increasing sediment toxicity affecting the sediment/water Hg (and MMHg) fluxes. In CNOR and BRR sediments, Hg availability and organic carbon were the main factors controlling MMHg production. Noteworthy, an upward MMHg diffusive flux was observed in winter that was inverted in summer. Although MMHg production increases in warmer month, the MMHg concentrations in overlying water increase in a higher proportion compared to the levels in porewaters. This opposite trend could be explained by different extension of MMHg demethylation in the water column. The high concentrations of Hg and MMHg and their dynamics in sediments are of major concern since they can cause an exportation of Hg from the contaminated areas up to ca. 14,600 mg year^?1 and an MMHg deposition of up to ca. 6000 mg year^?1. The results suggest that sediments from contaminated areas of Tagus estuary should be considered as a primary source of Hg for the water column and a sink of MMHg to the sedimentary column.     

Baseline susceptibility of spotted wing Drosophila (Drosophila suzukii) to four key insecticide classes

BACKGROUND

The invasive drosophilid pest, Drosophila suzukii Matsumura, is affecting berry production in most fruit‐producing regions of the world. Chemical control is the dominant management approach, creating concern for insecticide resistance in this pest. We compared the insecticide susceptibility of D. suzukii populations collected from conventional, organic or insecticide‐free blueberry sites.

RESULTS

The sensitivity of D. suzukii to malathion and spinetoram declined slightly across the 3 years of monitoring, whereas it was more consistent for methomyl and zeta‐cypermethrin. The sensitivity of D. suzukii to all four insecticides (LC₅₀ and LC₉₀ values) did not differ significantly among the blueberry fields using different management practices.

CONCLUSIONS

The baseline sensitivity of D. suzukii has been characterized, allowing future comparisons if field failures of chemical control are reported. The concentration achieving high control indicates that effective levels of control can still be achieved with field rates of these four insecticides. However, declining susceptibility of some populations of D. suzukii to some key insecticides highlights the need for resistance monitoring. © 2017 Society of Chemical Industry     

Pfaffia mosaic virus: a new potyvirus found infecting Pfaffia glomerata in Brazil

In Brazil plants of Pfaffia glomerata with mosaic symptoms were found to be infected with a previously undescribed potyvirus, Pfaffia mosaic virus (PfMV). Virus particles were long and flexuous, c.  10 × 700–800 nm, and cylindrical inclusions typical of potyviruses were present in cells of infected tissue. Partial host-range studies revealed that in addition to P. glomerata , PfMV infected only Chenopodium amaranticolor and Chenopodium quinoa . It was efficiently transmitted by the aphids Aphis gossypii and Myzus persicae . Polyclonal antiserum produced against the PfMV coat protein (CP) reacted with Potato virus Y (PVY), but not with four other potyviruses in PTA-ELISA. The similarity of the nucleotide sequence of the PfMV coat-protein gene ( CP ) varied from 7 to 76% when compared with other members of the family Potyviridae . Similarity of the 3' NTR sequence varied from 4 to 23%. In both cases the highest similarity was with PVY. These data indicate that PfMV is a new species in the genus Potyvirus .     

Aerobic Training, But Not Creatine, Modifies Longissimus Dorsi Muscle Composition

The goal of this study was to investigate by means of an ultrasound examination the composition of the longissimus dorsi muscle in 12 purebred Arabian horses submitted to aerobic training for 90 days, with and without creatine supplementation. Creatine supplementation was carried out by daily administration of 75 g creatine monohydrate mixed into the ration during 90 days of training. Physical conditioning was conducted on a high-performance treadmill, and training intensity was stipulated by calculating the velocity at which blood lactate reaches 4 mmol/l, determined monthly for each animal. The individual intensity of physical force was established at 80% of velocity that resulted in a blood lactate level of 4 mmol/l. The cross-sectional area and the thickness of the layer of fat of the longissimus dorsi muscle were measured for each group at the end of 8 months of inactivity and after 30, 60, and 90 days of training without (control groups) or with creatine supplementation (experimental groups). The results showed that aerobic training combined with or without creatine supplementation caused significant longissimus dorsi hypertrophy and reduction in the thickness of the fat layer. No beneficial effect from prolonged creatine supplementation on the body composition of horses was detected.     

Mimosa tenuiflora as a cause of malformations in ruminants in the northeastern Brazilian semiarid rangelands

Craniofacial anomalies, eye malformations, and permanent flexures of the forelimbs are common malformations seen in ruminants grazing semiarid rangelands of Northeastern Brazil. To investigate the cause of these malformations, we fed 2 suspected plants, Mimosa tenuiflora or Prosopis juliflora, to groups of 4 pregnant goats each. Fresh green M. tenuiflora was collected daily and fed ad libitum to 4 goats in group 1 throughout pregnancy. This treatment group also received a supplemental feed concentrate equivalent to 1% body weight. Four goats in group 2 received a ration with 70% of P. juliflora pods and 30% hay throughout pregnancy. Four control goats were fed supplemental feed concentrate (1% body weight) and hay ad libitum throughout pregnancy. Goats treated with P. juliflora pods and the control goats delivered 9 normal kids. The four goats that were fed M. tenuiflora during pregnancy delivered 4 kids, 3 of which had abnormalities similar to those observed in field cases, including cleft lip, unilateral corneal opacity, ocular bilateral dermoids, buphthalmos with a cloudy brownish appearance of the anterior chamber due to an iridal cyst, and segmental stenosis of the colon. Malformations induced experimentally by M. tenuiflora were similar to those observed in field cases, suggesting that M. tenuiflora is a cause of the field cases observed in the Brazilian semiarid rangelands.