Xylella fastidiosa in Olive in Apulia: Where We Stand.

A dramatic outbreak of Xylella fastidiosa decimating olive was discovered in 2013 in Apulia, Southern Italy. This pathogen is a quarantine bacterium in the European Union (EU) and created unprecedented turmoil for the local economy and posed critical challenges for its management. With the new emerging threat to susceptible crops in the EU, efforts were devoted to gain basic knowledge on the pathogen biology, host, and environmental interactions (e.g., bacterial strain(s) and pathogenicity, hosts, vector(s), and fundamental drivers of its epidemics) in order to find means to control or mitigate the impacts of the infections. Field surveys, greenhouse tests, and laboratory analyses proved that a single bacterial introduction occurred in the area, with a single genotype, belonging to the subspecies pauca, associated with the epidemic. Infections caused by isolates of this genotype turned to be extremely aggressive on the local olive cultivars, causing a new disease termed olive quick decline syndrome. Due to the initial extension of the foci and the rapid spread of the infections, eradication measures (i.e., pathogen elimination from the area) were soon replaced by containment measures including intense border surveys of the contaminated area, removal of infected trees, and mandatory vector control. However, implementation of containment measures encountered serious difficulties, including public reluctance to accept control measures, poor stakeholder cooperation, misinformation from some media outlets, and lack of robust responses by some governmental authorities. This scenario delayed and limited containment efforts and allowed the bacterium to continue its rapid dissemination over more areas in the region, as shown by the continuous expansion of the official borders of the infected area. At the research level, the European Commission and regional authorities are now supporting several programs aimed to find effective methods to mitigate and contain the impact of X. fastidiosa on olives, the predominant host affected in this epidemic. Preliminary evidence of the presence of resistance in some olive cultivars represents a promising approach currently under investigation for long-term management strategies. The present review describes the current status of the epidemic and major research achievements since 2013.

Multiple rare genetic variants co-segregating with familial IgA nephropathy all act within a single immune-related network.

BACKGROUND: IgA nephropathy (IgAN) is a common complex disease with a strong genetic involvement. We aimed to identify novel, rare, highly penetrant risk variants combining family-based linkage analysis with whole-exome sequencing (WES). METHODS: Linkage analysis of 16 kindreds of South Italian ancestry was performed using an 'affected-only' strategy. Eight most informative trios composed of two familial cases and an intrafamilial control were selected for WES. High-priority variants in linked regions were identified and validated using Sanger sequencing. Custom TaqMan assays were designed and carried out in the 16 kindreds and an independent cohort of 240 IgAN patients and 113 control subjects. RESULTS: We found suggestive linkage signals in 12 loci. After sequential filtering and validation of WES data, we identified 24 private or extremely rare (MAF <0.0003) linked variants segregating with IgAN status. These were present within coding or regulatory regions of 23 genes that merged into a common functional network. The genes were interconnected by AKT, CTNNB1, NFKB, MYC and UBC, key modulators of WNT/ß-catenin and PI3K/Akt pathways, which are implicated in IgAN pathogenesis. Overlaying publicly available expression data, genes/proteins with expression notably altered in IgAN were included in this immune-related network. In particular, the network included the glucocorticoid receptor gene, NR3C1, which is the target of corticosteroid therapy routinely used in the treatment of IgAN. CONCLUSION: Our findings suggest that disease susceptibility could be influenced by multiple rare variants acting in a common network that could provide the starting point for the identification of potential drug targets for personalized therapy.

Genetic Variability of Grapevine Pinot gris virus and Its Association with Grapevine Leaf Mottling and Deformation.

The role of Grapevine Pinot gris virus (GPGV) in the etiology of grapevine leaf mottling and deformation was investigated by biological and molecular assays. A survey on different cultivars from the Trentino Region in Italy showed a widespread distribution of GPGV, which was associated with symptomatic (79%) but also with symptomless (21%) vines. Symptomatic and GPGV-infected 'Pinot gris' vines induced symptoms on grafted vines of healthy Pinot gris or 'Traminer', whereas GPGV-infected but symptomless vines did not. High-throughput sequencing of small RNA (sRNA) populations of two infected Pinot gris accessions confirmed the existence of nearly overlapping viromes in vines with or without symptoms but phylogenetic analyses of the genomes of seven GPGV isolates from Italy and the Czech and Slovak Republics clearly differentiated those infecting symptomatic vines. The involvement of Grapevine rupestris vein feathering virus (GRVFV) in the disease, which was only infecting the symptomatic vine, was ruled out by reverse-transcription polymerase chain reaction studies. Maximum likelihood and Bayesian phylogenetic analysis of two GPGV genomic regions, encompassing part of the movement protein (MP) and coat protein gene sequences and the RNA-dependent RNA polymerase domain of the replicase gene, showed that isolates from symptomatic vines form a lineage distinct from that of symptomless vines. Moreover, the presence or lack of the MP stop codon identified in viral isolates from symptomatic or symptomless vines, respectively, is likely responsible for an MP six amino acids longer in symptomless isolates.

Identification and characterization of citrus yellow vein clearing virus, a putative new member of the genus Mandarivirus.

Molecular features and genomic organization were determined for Citrus yellow vein clearing virus (CYVCV), the putative viral causal agent of yellow vein clearing disease of lemon trees, reported in Pakistan, India, and more recently in Turkey and China. CYVCV isolate Y1 from Adana, Turkey, was used for deep sequencing analysis of the virus-induced small RNA fractions and for mechanical and graft inoculation of herbaceous and citrus indicator plants. A polyclonal antiserum was developed from CYVCV-Y1 purified from Phaseolus vulgaris and used in western blot assays to characterize the coat protein of CYVCV-Y1 and determine its serological relationship with related viruses. Contigs assembled from the Illumina sequenced short reads were used to construct the whole genome of Citrus yellow vein clearing virus (CYVCV), consisting in a positive-sense RNA of 7,529 nucleotides and containing six predicted open reading frames. The CYVCV genome organization and size resembled that of flexiviruses, and search for sequence homologies revealed that Indian citrus ringspot virus (ICRSV) (Mandarivirus, Alphaflexiviridae) is the most closely related virus. However, CYVCV had an overall nucleotide sequence identity of ≈74% with ICRSV. Although the two viruses were similar with regard to genome organization, viral particles, and herbaceous host range, CYVCV caused different symptoms in citrus and was serologically distinct from ICRSV. Primer pairs were designed and used to detect the virus by conventional and quantitative reverse transcription-polymerase chain reaction on yellow vein clearing symptomatic field trees as well as graft- and mechanically inoculated host plants. Collectively, these data suggest that CYVCV is the causal agent of yellow vein clearing disease and represents a new species in the genus Mandarivirus.

Treatment of refractory adult-onset pityriasis rubra pilaris with TNF-alpha antagonists: a case series.

BACKGROUND: Pityriasis rubra pilaris (PRP) is a rare inflammatory dermatosis with frequent clinical presentation as erythroderma. Conventional systemic treatment is often unsatisfactory and limited by long-term toxicity. The use of tumour necrosis factor (TNF) antagonists has been reported previously in single cases, but lacking long-term follow-up or comparison between different biological agents. OBJECTIVES: To assess the long-term efficacy and safety of TNF-alpha antagonist, infliximab and etanercept, either in monotherapy or in combination therapy of severe, refractory adult-onset PRP. METHODS: Seven patients of adult-onset PRP, six newly diagnosed type-I and 1 type-II, which were resistant or ineligible to conventional systemic treatment, received a single course of infliximab or etanercept therapy, alone or in combination with low-dose acitretin (>0.25 mg/kg/daily). After complete remission and treatment discontinuation, a follow-up period of 12 months was evaluated for relapses. RESULTS: Six patients obtained complete remission after a single course of anti-TNF-alpha therapy: mean therapy duration was 19.3 weeks (range 6-48 weeks). All patients obtained significant clearing (>75% of body surface area) of skin lesions at week 12. Two patients with marked keratoderma developed localized disease recurrence during treatment. During follow-up, only a single patient, affected by type II PRP, had disease relapse. CONCLUSIONS: Both TNF-alpha antagonists proved successful for the treatment of refractory, adult-onset PRP, yielding complete and persistent clinical responses in type-I PRP. Infliximab was associated with a more rapid onset of action, while treatment duration was comparable with etanercept. PRP type II warranted long-term therapy and showed relapse after drug discontinuation.

Squamous cell carcinoma arising in a venous ulcer as a complication of the Klippel-Trenaunay syndrome.

Klippel-Trenaunay (KT) syndrome is a vascular malformation characterized by a port-wine stain, varicose veins and hypertrophy of the affected limb. Ulceration is considered an uncommon complication of KT syndrome and occurrence of skin cancer has been previously reported only in one case. We observed a case of KT syndrome in a 48-year-old woman who developed a large ulcer and a squamous cell carcinoma on the affected leg.