Cadophora sabaouae sp. nov. and Phaeoacremonium Species Associated with Petri Disease on Grapevine Propagation Material and Young Grapevines in Algeria.

A field survey conducted on asymptomatic grapevine propagation material from nurseries and symptomatic young grapevines throughout different regions of Algeria yielded a collection of 70 Phaeoacremonium-like isolates and three Cadophora-like isolates. Based on morphology and DNA sequence data of ß-tubulin (tub2) and actin, five Phaeoacremonium species were identified including Phaeoacremonium minimum (22 isolates), Phaeoacremonium venezuelense (19 isolates), Phaeoacremonium parasiticum (17 isolates), Phaeoacremonium australiense (8 isolates), and Phaeoacremonium iranianum (4 isolates). The latter two species (P. australiense and P. iranianum) were reported for the first time in Algeria. Multilocus phylogenetic analyses (internal transcribed spacer, tub2, and translation elongation factor 1-α) and morphological features, allowed the description of the three isolates belonging to the genus Cadophora (WAMC34, WAMC117, and WAMC118) as a novel species, named Cadophora sabaouae sp. nov. Pathogenicity tests were conducted on grapevine cuttings cultivar Cardinal. All the identified species were pathogenic on grapevine cuttings.

Epigenetic Modulating Chemicals Significantly Affect the Virulence and Genetic Characteristics of the Bacterial Plant Pathogen Xanthomonas campestris pv. campestris.

Epigenetics is the study of heritable alterations in phenotypes that are not caused by changes in DNA sequence. In the present study, we characterized the genetic and phenotypic alterations of the bacterial plant pathogen Xanthomonas campestris pv. campestris (Xcc) under different treatments with several epigenetic modulating chemicals. The use of DNA demethylating chemicals unambiguously caused a durable decrease in Xcc bacterial virulence, even after its reisolation from infected plants. The first-time use of chemicals to modify the activity of sirtuins also showed some noticeable results in terms of increasing bacterial virulence, but this effect was not typically stable. Changes in treated strains were also confirmed by using methylation sensitive amplification (MSAP), but with respect to registered SNPs induction, it was necessary to consider their contribution to the observed polymorphism. The molecular basis of the altered virulence was deciphered by using dualRNA-seq analysis of treated Xcc strains infecting Brassica rapa plants. The results of the present study should promote more intensive research in the generally understudied field of bacterial epigenetics, where artificially induced modification by epigenetic modulating chemicals can significantly increase the diversity of bacterial properties and potentially contribute to the further development of the fields, such as bacterial ecology and adaptation.

Anatomy of the vestibulum esophagi and surgical implications during prosthetic laryngoplasty in horses.

OBJECTIVE: To describe the anatomy of the entry to the equine esophagus (vestibulum esophagi) and to assess the risk of penetrating its adventitia and/or lumen during laryngoplasty. STUDY DESIGN: Ex vivo cadaveric study. SAMPLE POPULATION: Five isolated equine larynges and 39 equine head and neck specimens. METHODS: The anatomy of the vestibulum esophagi was studied by dissection of 5 cadaver specimens. Then, a bilateral laryngoplasty was performed, including 5 suture placements through the muscular processes, caudal, rostral, and sagittal, with straight and curved needles. Two of the 3 surgeons performing the implantations were unaware of the goals of the study. Suture positions and iatrogenic trauma to the lumen and/or adventitia of the vestibulum esophagi were identified during dissection of the specimens. Risk factors for penetrating the adventitia were evaluated with a multivariate regression model. RESULTS: The vestibulum esophagi spans between both wings of the thyroid cartilage over the entire width of the larynx, covering the rostral spine (arcuate crest) of the arytenoid cartilages. It is covered by the thyropharyngeus and cricopharyngeus muscles. Masked surgeons were associated with a significantly higher number of adventitia penetrations (72%) compared to the nonmasked surgeon (9%). The lumen of the vestibulum esophagi was penetrated in 4.6% of suture placements and only by the 2 masked surgeons. CONCLUSION: Penetration of the adventitia was more common when surgeons were unaware of the anatomical extent of the vestibulum esophagi. CLINICAL SIGNIFICANCE: Anatomical knowledge of the extent of the vestibulum esophagi reduces the risk of penetrating its lumen or adventitia during suture placement on the muscular process of the arytenoid cartilage.