New Populations of Sclerotinia sclerotiorum from Lettuce in California and Peas and Lentils in Washington

ABSTRACT Four populations of Sclerotinia sclerotiorum in North America were inferred previously, based on analyses of both rapidly evolving markers (DNA fingerprint and mycelial compatiblity), and multilocus DNA sequence spanning the range between fast and slow evolution. Each population was defined as an interbreeding unit of conspecific individuals sharing a common recent ancestor and arising in a unique evolutionary event. The present study applies this standard to extend characterization of S. sclerotiorum populations to the Western United States. Isolates of S. sclerotiorum (N = 294) were determined to represent three genetically differentiated populations: California (CA, lettuce), Washington (WA, pea/lentil), and Ontario (ON, lettuce). CA was the most diverse population yet sampled in North America. Clonality was detected in ON and WA. No DNA fingerprints were common among the populations. The index of association (I(A)), based on fingerprint, was closer to zero (0) for CA than it was for the other populations. High diversity and lack of association of markers in California are consistent either with genetic exchange and recombination, or with large population size and high standing genetic variation. Intra- and interlocus conflict among three DNA sequence loci was consistent with recombination. The coalescent IGS genealogy confirmed subdivision and showed CA to be older than WA or ON. The Nearest Neighbor statistic on combined data confirmed subdivision among all present and previously defined populations. All isolates had both MAT1-1 and MAT1-2, consistent with uniform homothallism.     

Three-dimensional reconstruction of partially 3D-digitized peach tree canopies

A simplified method for building three-dimensional (3D) mock-ups of peach trees is presented. The method combines partial digitizing of tree structure with reconstruction rules for non-digitized organs. Reconstruction was applied at two scales: leaves on current-year shoots (CYS) and shoots on 1-year-old shoots (OYOS). Reconstruction rules make use of allometric relationships, random sampling of shoot attribute distribution and additional hypotheses (e.g., constant internode length). The method was quantitatively assessed for two training systems (tight goblet and wide-double-Y), at a range of spatial scales. For this purpose, light interception properties of reference and reconstructed mock-ups were compared. Mock-up quality depended on scale. Foliage reconstruction on CYS was unsuitable for generating a given CYS. Similarly, CYS reconstruction on OYOS was unsuitable for generating a given OYOS. This is because generic rules derived at the population scale do not consider specific foliage or shoot attributes of a given CYS or OYOS. In contrast, foliage reconstruction on CYS was able to generate OYOS mock-ups having light properties similar to the reference mock-ups. The same held for CYS reconstruction on OYOS for light capture properties at the tree scale. The CYS reconstruction on OYOS was also suitable for deriving OYOS distribution as a function of light interception ability. Reconstruction rules were successfully used to build the vegetation neighborhood of a reference shoot. The proposed method could therefore be used to make 3D tree mock-ups usable for a range of some, but not all, light computations. Because the simplified method allows large time savings, it could be used in virtual experiments requiring large numbers of replicates, such as comparative studies of tree genotypes or training systems.     

Influence of the stage for anther excision and heterostyly in embryogenesis induction from eggplant anther cultures

In this work we address two aspects of eggplant flower biology potentially involved on the efficiency of anther culture: the selection of the best floral stage to extract anthers for culture, and the effect of heterostyly in the identification of suitable buds and anthers. For 12 different accessions, we determined morphological criteria (length ranges) to identify buds and anthers enriched in vacuolate microspores and young bicellular pollen, the stages most responsive to embryogenesis induction. While these microspore/pollen stages were the most responsive when isolated and cultured in liquid medium, we observed that culture of anthers containing these stages is not the best choice. Instead, the highest response was found for younger anthers, containing mostly young and mid microspores. We analyzed eggplant anther walls and found that their particular thickness may be behind this apparent discrepancy, since they may delay the diffusion of inducing factors to the anther locule, reducing their effect over inducible microspores. Thus, the culture of younger anthers would allow for younger microspores to grow up to the inducible stages while factors are entering the locule. We also analyzed the embryogenic response of short and long-styled buds present in Cristal, a heterostylic cultivar. Our results demonstrated that each floral morph produced buds and anthers of different lengths, but equally useful for anther culture, since similar amounts of embryos were produced. The practical application of these results may improve the efficiency of anther culture not only in these cultivars, but in others also presenting thick anther walls and heterostyly.     

Evaluation of modified vaccinia virus Ankara expressing VP2 protein of infectious bursal disease virus as an immunogen in chickens

A recombinant modified vaccinia Ankara (MVA) virus expressing mature viral protein 2 (VP2) of the infectious bursal disease virus (IBDV) was constructed to develop MVA-based vaccines for poultry. We demonstrated that this recombinant virus was able to induce a specific immune response by observing the production of anti-IBDV-seroneutralizing antibodies in specific pathogen-free chickens. Besides, as the epitopes of VP2 responsible to induce IBDV-neutralizing antibodies are discontinuous, our results suggest that VP2 protein expressed from MVA-VP2 maintained the correct conformational structure. To our knowledge, this is the first report on the usefulness of MVA-based vectors for developing recombinant vaccines for poultry.     

Hoof disorders, locomotion ability and lying times of cubicle-housed compared to pasture-based dairy cows

Forty six spring-calving Holstein–Friesians (12 primiparous, 34 pluriparous) were block-paired (expected calving date, parity, body condition score and genetic merit) and allocated to either a PASTURE or HOUSED system for a full production cycle (− 40 to 305 days relative to calving). Both hind claws were inspected on six occasions (− 40, 10, 35, 85, 120 and 210 days relative to calving) to determine the severity of 5 disorders (sole and white line area haemorrhages, white line disease, heel horn erosion, digital dermatitis and other lesions). Six aspects of locomotion ability (tracking, spine curvature, speed, head bobbing, general symmetry and abduction/adduction) were assessed from 1 (normal) to 5 (abnormal) every 2 weeks. Throughout the study records of clinical lameness were kept for all animals. Lying times of 26 block-paired cows (PASTURE n = 13, HOUSED n = 13) were recorded automatically every 5 min for 48 h at 33, 83 and 193 days post-calving. Data were analysed using mixed models for repeated measures, logistic regression and survival analysis, as appropriate. The severity of hoof disorders was lower for PASTURE compared to HOUSED cows from 85 days post-calving onwards (P < 0.05). HOUSED cows had a greater hazard ratio (P < 0.01) of presenting an abnormal (i.e. scoring ≥ 3) tracking (2.8), spine curvature (2.3), head bobbing (3.6), general symmetry (3.0), abduction/adduction (4.2) and for the average (3.9) of all locomotion aspects investigated (i.e. abnormal locomotion). Furthermore, HOUSED cows had a greater odds ratio (6.5, P < 0.01) of clinical lameness from day 180 post-calving onwards. Mean total lying times per 48 h period were shorter (P < 0.001) for HOUSED compared to PASTURE cows (18.1 h, SE 0.71 vs. 20.5 h, SE 0.73). In summary, from day 85 post-calving to the end of the production cycle PASTURE cows had less severe hoof disorders, better locomotion ability and reduced likelihood of clinical lameness compared to similar cows in a HOUSED system. The PASTURE system also facilitated longer, undisrupted lying times that have beneficial implications for lameness. A PASTURE system therefore improved cow welfare in terms of lameness compared to a HOUSED system.     

Parasitic encephalitis caused by Stephanurus dentatus in a pig in Brazil

A pig was in left lateral recumbency with limb spasticity, accentuated prostration, and strabismus, and was euthanized. During autopsy, yellowing of the leptomeninges at the ventral pons to medulla oblongata was noted. In the cerebellar peduncles, there was a focally extensive black-to-yellow area at the level of the vestibular nuclei. Histologic examination revealed a cross-section of a nematode larva, consistent with Stephanurus dentatus, bordered by edema and marked infiltration of mononuclear cells, plasma cells, and a few eosinophils. Vacuolation of the neuropil, with rare gitter cells and axonal spheroids, was also observed. We diagnosed parasitic encephalitis caused by S. dentatus migration based on the pathology findings and characterization of the parasite.