Apricot yellows associated with ‘Candidatus Phytoplasma phoenicium’ in Iran

Almond witches’ broom associated with ‘Candidatus Phytoplasma phoenicium’ is an economically important disease of almond in Iran and Lebanon. During surveys of almond witches’ broom in 2012–2015, an apricot yellows disease was observed in Fars Province of Iran. The characteristic symptoms of the disease were leaf yellowing, inward leaf curl, scorch of leaf margins, shortened internodes, production of rosettes at the tips of the branches, and decline, stunting, and death of affected trees. Healthy bitter almond and apricot seedlings, grafted with shoots from symptomatic trees, exhibited phytoplasma-type symptoms. A 16S rDNA fragment of 1,250 bp was amplified by nested-PCR from affected trees and grafted seedlings. Nucleotide sequence identity, presence of species-specific signature sequences, and phylogenetic analysis of 16S rDNA allowed the assignation of the phytoplasma strains identified to the ‘Ca. P. phoenicium’. In vitro and in silico RFLP analyses of the amplified fragment allowed affiliation of the apricot yellows phytoplasma to a molecular variant in the subgroup 16SrIX-B. Within the population strains identified in this and previous studies, 16 genetic lineages were determined within 16S rDNA nucleotide sequences by the combination of 19 single nucleotide polymorphisms. The apricot yellows phytoplasma strains belong to a unique genetic lineage distinguished by the presence of three lineage-specific SNPs. This first report of ‘Ca. P. phoenicium’ in association with apricot yellows in Iran opens new perspectives on the epidemiology of almond witches’ broom, suggesting possible adaptation of the phytoplasma to other fruit tree species

Bacterial Communities in the Embryo of Maize Landraces:Relation with Susceptibility to Fusarium Ear Rot

Locally adapted maize accessions (landraces) represent an untapped resource of nutritional and resistance traits for breeding, including the shaping of distinct microbiota. Our study focused on five different maize landraces and a reference commercial hybrid, showing different susceptibility to fusarium ear rot, and whether this trait could be related to particular compositions of the bacterial microbiota in the embryo, using different approaches. Our cultivation-independent approach utilized the metabarcoding of a portion of the 16S rRNA gene to study bacterial populations in these samples. Multivariate statistical analyses indicated that the microbiota of the embryos of the accessions grouped in two different clusters: one comprising three landraces and the hybrid, one including the remaining two landraces, which showed a lower susceptibility to fusarium ear rot in field. The main discriminant between these clusters was the frequency of Firmicutes, higher in the second cluster, and this abundance was confirmed by quantification through digital PCR. The cultivation-dependent approach allowed the isolation of 70 bacterial strains, mostly Firmicutes. In vivo assays allowed the identification of five candidate biocontrol strains against fusarium ear rot. Our data revealed novel insights into the role of the maize embryo microbiota and set the stage for further studies aimed at integrating this knowledge into plant breeding programs

Multiple gene analyses identify distinct “bois noir” phytoplasma genotypes in the Republic of Macedonia

“Bois noir” (BN) is a grapevine yellows disease, associated with phytoplasma strains related to ‘Candidatus Phytoplasma solani’, that causes severe losses to viticulture in the Euro-Mediterranean basin. Due to the complex ecological cycle of its etiological agent, BN epidemiology is only partially known, and no effective control strategies have been developed. Numerous studies have focused on molecular characterization of BN phytoplasma strains, to identify molecular markers useful to accurately describe their genetic diversity, geographic distribution and host range. In the present study, a multiple gene analysess were carried out on 16S rRNA, tuf, vmp1, and stamp genes to study the genetic variability among 18 BN phytoplasma strains detected in diverse regions of the Republic of Macedonia. Restriction fragment length polymorphism (RFLP) assays showed the presence of one 16S rRNA (16SrXII-A), two tuf (tuf-type a, tuf-type b), five vmp1 (V2-TA, V3, V4, V14, V18), and three stamp (S1, S2, S3) gene patterns among the examined strains. Based on the collective RFLP patterns, seven genotypes (Mac1 to Mac7) were described as evidence for genetic heterogeneity, and highlighting their prevalence and distribution in the investigated regions. Phylogenetic analyses on vmp1 and stamp genes underlined the affiliation of Macedonian BN phytoplasma strains to clusters associated with distinct ecologies

First pilot case-control interventional study using autologous extracellular vesicles to treat chronic venous ulcers unresponsive to conventional treatments

Current therapeutic approaches for chronic venous ulcers (CVUs) still require evidence of effectiveness. Diverse sources of extracellular vesicles (EVs) have been proposed for tissue regeneration, however the lack of potency tests, to predict in-vivo effectiveness, and a reliable scalability have delayed their clinical application. This study aimed to investigate whether autologous serum-derived EVs (s-EVs), recovered from patients with CVUs, may be a proper therapeutic approach to improve the healing process. A pilot case-control interventional study (CS2/1095/0090491) has been designed and s-EVs recovered from patients. Patient eligibility included two or more distinct chronic lesions in the same limb with 11 months as median persistence of active ulcer before enrollment. Patients were treated three times a week, for 2 weeks. Qualitative CVU analysis demonstrated that s-EVs-treated lesions displayed a higher percentage of granulation tissue compared to the control group (Sham) (s-EVs 3 out of 5: 75–100 % vs Sham: none), further confirmed at day 30. s-EVs-treated lesions also displayed higher sloughy tissue reduction at the end of treatment even increased at day 30. Additionally, s-EV treatment led to a median surface reduction of 151 mm2 compared to 84 mm2 in the Sham group, difference even more evident at day 30 (s-EVs 385 mm2 vs Sham 106 mm2 p = 0.004). Consistent with the enrichment of transforming growth factor-β1 in s-EVs, histological analyses showed a regenerative tissue with an increase in microvascular proliferation areas. This study first demonstrates the clinical effectiveness of autologous s-EVs in promoting the healing process of CVUs unresponsive to conventional treatments

Identification of new 16SrIX subgroups, -F and -G, among ‘Candidatus Phytoplasma phoenicium’ strains infecting almond, peach and nectarine in Lebanon

Almond witches’-broom is a lethal almond disease associated with ‘Candidatus Phytoplasma phoenicium’, subgroups 16SrIX-B and -D. In Lebanon, where the disease was first reported, analogous diseases affecting peach and nectarine were recently associated with presence of ‘Ca. P. phoenicium’. In the present study, genetic diversity among 24 ‘Ca. P. phoenicium’ strains infecting almond, peach and nectarine plants in diverse geographic regions of Lebanon was investigated by virtual restriction fragment length polymorphism (RFLP) analysis of 16S rDNA nucleotide sequences. Calculation of virtual restriction similarity coefficients revealed the presence of two new subgroups, -F and -G, in group 16SrIX that were confirmed by real RFLP analyses. Obtained results open new opportunities for in-depth studies of the distribution of ‘Ca. P. phoenicium’ strains in plant hosts and insect vector populations from different geographic areas of Lebanon

Dissecting the susceptibility/resistance mechanism of Vitis vinifera for the future control of downy mildew

23CO.NA.VI. 2020 – 8° Convegno Nazionale di Viticoltura, Udine, Italy, July 5-7, 2021openInternationalBothThe Eurasian grapevine (Vitis vinifera), a species cultivated worldwide for high-quality wine production, is extremely susceptible to the agent of downy mildew, Plasmopara viticola. Nevertheless, germplasm from Georgia (Southern Caucasus, the first grapevine domestication centre), characterized by a high genetic variability, showed resistance traits to P. viticola. The cultivar Mgaloblishvili exhibited the most promising phenotype in terms of resistance against P. viticola. Its defence response results in: i) low disease intensity; ii) low sporulation; iii) damaged mycelium; iv) production of antimicrobial compounds such as volatile organic compounds (VOCs), whose effectiveness on the pathogen was evaluated by leafdisc assays. At the transcriptomic level, its resistance mechanism is determined by the differential expression of both resistance and susceptible genes. The resistance genes are related to: i) pathogen recognition through PAMP, DAMP and effector receptors; ii) ethylene signalling pathway; iii) synthesis of antimicrobial compounds (VOCs) and fungal wall degrading enzymes; iv) development of structural barriers (cell wall reinforcement). The first putative susceptible gene was the transcription factor VviLBDIf7 gene, whose validation was carried out by dsRNA (double-stranded RNA) assay. In this work, these unique results on plant-pathogen interaction are reviewed with the aim of developing new strategies to control the disease.openRicciardi, Valentina; Marcianò, Demetrio; Sargolzaei, Maryam; Marrone Fassolo, Elena; Fracassetti, Daniela; Brilli, Matteo; Moser, Mirko; Vahid, Shariati J.; Tavakole, Elahe; Maddalena, Giuliana; Passera, Alessandro; Casati, Paola; Pindo, Massimo; Cestaro, Alessandro; Costa, Alex; Bonza, Maria Cristina; Maghradze, David; Tirelli, Antonio; Failla, Osvaldo; Bianco, Piero Attilio; Quaglino, Fabio; Toffolatti, Silvia Laura; De Lorenzis, GabriellaRicciardi, V.; Marcianò, D.; Sargolzaei, M.; Marrone Fassolo, E.; Fracassetti, D.; Brilli, M.; Moser, M.; Vahid, S.J.; Tavakole, E.; Maddalena, G.; Passera, A.; Casati, P.; Pindo, M.; Cestaro, A.; Costa, A.; Bonza, M.C.; Maghradze, D.; Tirelli, A.; Failla, O.; Bianco, P.A.; Quaglino, F.; Toffolatti, S.L.; De Lorenzis, G

MC1R variants in childhood and adolescent melanoma: a retrospective pooled analysis of a multicentre cohort.

BACKGROUND: Germline variants in the melanocortin 1 receptor gene (MC1R) might increase the risk of childhood and adolescent melanoma, but a clear conclusion is challenging because of the low number of studies and cases. We assessed the association of MC1R variants with childhood and adolescent melanoma in a large study comparing the prevalence of MC1R variants in child or adolescent patients with melanoma to that in adult patients with melanoma and in healthy adult controls. METHODS: In this retrospective pooled analysis, we used the M-SKIP Project, the Italian Melanoma Intergroup, and other European groups (with participants from Australia, Canada, France, Greece, Italy, the Netherlands, Serbia, Spain, Sweden, Turkey, and the USA) to assemble an international multicentre cohort. We gathered phenotypic and genetic data from children or adolescents diagnosed with sporadic single-primary cutaneous melanoma at age 20 years or younger, adult patients with sporadic single-primary cutaneous melanoma diagnosed at age 35 years or older, and healthy adult individuals as controls. We calculated odds ratios (ORs) for childhood and adolescent melanoma associated with MC1R variants by multivariable logistic regression. Subgroup analysis was done for children aged 18 or younger and 14 years or younger. FINDINGS: We analysed data from 233 young patients, 932 adult patients, and 932 healthy adult controls. Children and adolescents had higher odds of carrying MC1R r variants than did adult patients (OR 1·54, 95% CI 1·02-2·33), including when analysis was restricted to patients aged 18 years or younger (1·80, 1·06-3·07). All investigated variants, except Arg160Trp, tended, to varying degrees, to have higher frequencies in young patients than in adult patients, with significantly higher frequencies found for Val60Leu (OR 1·60, 95% CI 1·05-2·44; p=0·04) and Asp294His (2·15, 1·05-4·40; p=0·04). Compared with those of healthy controls, young patients with melanoma had significantly higher frequencies of any MC1R variants. INTERPRETATION: Our pooled analysis of MC1R genetic data of young patients with melanoma showed that MC1R r variants were more prevalent in childhood and adolescent melanoma than in adult melanoma, especially in patients aged 18 years or younger. Our findings support the role of MC1R in childhood and adolescent melanoma susceptibility, with a potential clinical relevance for developing early melanoma detection and preventive strategies. FUNDING: SPD-Pilot/Project-Award-2015; AIRC-MFAG-11831