Xylella fastidiosa subsp. pauca, Neofusicoccum spp. and the decline of olive trees in salento (Apulia, Italy). Comparison of symptoms, possible interactions, certainties and doubts

Xylella fastidiosa subsp. pauca (XFP), Neofusicoccum mediterraneum, N. stellenboschiana and other fungi have been found in olive groves of Salento (Apulia, Italy) that show symptoms of severe decline. XFP is well known to be the cause of olive quick decline syndrome (OQDS). It has also been assessed that Neofusicoccum spp. causes a distinct disease syndrome, namely, branch and twig dieback (BTD). All these phytopathogens incite severe symptoms that can compromise the viability of large canopy sectors or the whole tree. However, their specific symptoms are not easily distinguished, especially during the final stages of the disease when branches are definitively desiccated. By contrast, they can be differentiated during the initial phases of the infection when some facets of the diseases are typical, especially wood discoloration, incited solely by fungi. Here, we describe the typical symptomatological features of OQDS and BTD that can be observed in the field and that have been confirmed by Koch postulate experiments. Similar symptoms, caused by some abiotic adverse conditions and even by additional biotic factors, are also described. Thus, this review aims at: (i) raising the awareness that declining olive trees in Salento do not have to be linked a priori to XFP; (ii) defining the guidelines for a correct symptomatic diagnosis to orient proper laboratory analyses, which is crucial for the application of effective control measures. The possibility that bacterium and fungi could act as a polyspecies and in conjunction with predisposing abiotic stresses is also widely discussed

Identification and characterization of Neofusicoccum stellenboschiana in branch and twig dieback-affected olive trees in Italy and comparative pathogenicity with N. mediterraneum

For about a decade, olive groves in Apulia (Southern Italy) have been progressively destroyed by Olive Quick Decline Syndrome (OQDS), a disease caused by the bacterium Xylella fastidiosa subsp. pauca (Xfp). Recently, we described an additional wilting syndrome affecting olive trees in that area. The botryosphaeriaceous fungus Neofusicoccum mediterraneum was found associated with the diseased trees, and its high virulence toward olive trees was demonstrated. Given the common features with Branch and Twig Dieback (BTD) of olive tree, occurring in Spain and California, we suggested that the observed syndrome was BTD. During our first survey, we also found a botryosphaeriaceous species other than N. mediterraneum. In the present article, we report the morphological and molecular characterization of this fungal species which we identified as Neofusicoccum stellenboschiana. In the study, we also included for comparison additional N. stellenboschiana isolates obtained from olive trees in Latium and Tuscany region (Central Italy). The occurrence of N. stellenboschiana in olive trees is reported here for the first time in the northern hemisphere. The pathogenicity and virulence were tested in nine inoculation trials, where the Apulian N. stellenboschiana isolate was compared with the isolate from Latium and with the Apulian isolate of N. mediterraneum. Both isolates of N. stellenboschiana proved pathogenic to olive trees. They caused evident bark canker and wood discolouration when inoculated at the base of the stem of two/three-year-old trees and on one-year-old twigs. However, virulence of N. stellenboschiana was significantly lower, though still remarkable, compared with N. mediterraneum in term of necrosis rogression in the bark and the wood and capacity of wilting the twigs. Virulence of N. stellenboschiana and N. mediterraneum did not substantially change when noculations were performed in spring/summer and in autumn, suggesting that these fungal species have the potential to infect and damage olive trees in all seasons. The high thermotolerance of N. stellenboschiana was also revealed with in vitro growth and survival tests. The high virulence of these otryosphaeriaceae species highlights their contribution in BTD aetiology and the necessity to investigate right away their diffusion and, possibly, the role of additional factors other than Xfp in the general decline of olive groves in Apulia. Hence the importance of assessing the degree of overlap of BTD/Botryosphariaceae with OQDS/Xfp is discussed

Actual cost of electricity: An economic index to overcome levelized cost of electricity limits

The selection of renewable energy technologies is widely based on the economic index levelized cost of electricity (LCOE). However, the LCOE ignores the potential temporal mismatch between electricity generation and actual grid demand: this aspect is accounted for in the new index named actual cost of electricity (ACOE), here proposed. This index provides a more accurate economic assessment of renewable energy, minimizing the number of assumptions to be made and outlining the benefits of including a storage. The proposed index is tested across ten cases encompassing three renewable technologies: wind, photovoltaic, and concentrated solar power. The outcomes show that the actual renewable electricity generation of a plant can be reduced by 40%–50% when accounting for the actual electricity demand, resulting in an ACOE exceeding the LCOE by up to 100/150 $/MWh. In addition, the ACOE enables the identification of breakthrough conditions that make storage adoption economically feasible.</p

Identification of an actionable mutation of KIT in extraskeletal myxoid chondrosarcoma (EMC)

Background: EMC is an extremely rare soft tissue sarcoma, marked by a translocation involving NR4A3 gene. EMC are usually indolent and generally are moderately sensitive to anthracycline-based chemotherapy; we reported on the therapeutic activity of sunitinib in a series of EMC cases, however the molecular target of sunitinib in EMC is unknown. In addition, there is still the need to identify alternative therapeutic strategies. To better characterize the molecular background of this disease we performed whole transcriptome sequencing (WTS) in a small series of EMC identifying a case carrying an activating KIT mutation. Methods: Five EMC, positive for EWSR1-NR4A3 in FISH, were collected for WTS analysis. KIT phosphorylation was evaluated through Western Blot. KIT hotspot exons were sequenced through Sanger method in these cases and in an additional cohort of 15 EMC FFPE samples. Results: Presence of the chimeric EWSR1-NR4A3 mRNA was confirmed in all cases by WTS and no additional fusion event was identified. In concordance with previous reports, exon12/exon3 EWSR1-NR4A3 fusion was the most frequent breakpoint detected (sample #2, #3 and #5). While exon7/exon2 and exon13/exon3 were detected respectively in sample #1 and #4. Pathogenic SNV and INDEL were searched starting from WTS data. Peculiarly, in sample #1 an in-frame deletion (c.1735_1737delGAT p.D579del) was identified in exon 11 of KIT. The deletion was somatic and heterozygous and was validated both at DNA and mRNA level. Sample #1 showed a marked high expression of KIT at mRNA level (9.8 fold greater than in the other 4 cases) and a mild phosphorylation of the receptor. KIT p.D579del is known to predict response to TKI treatment in GIST. However, Sanger sequencing of KIT in additional 15 FFPE EMC did not show any other mutated cases. Conclusions: Exon 11 KIT mutation has been detected in one out of 20 EMC cases analyzed, indicating that KIT alteration is not a recurrent event in EMC and thus it could not explain the sensitivity of these tumors to sunitinib. Its role in the pathogenesis of EMC is left to be determined. No additional unknown fusion and/or mutation were detected

Identification of an Actionable Mutation of KIT in a Case of Extraskeletal Myxoid Chondrosarcoma

Extraskeletal myxoid chondrosarcoma (EMC) is an extremely rare soft tissue sarcoma, marked by a translocation involving the NR4A3 gene. EMC is usually indolent and moderately sensitive to anthracycline-based chemotherapy. Recently, we reported on the therapeutic activity of sunitinib in a series of EMC cases, however the molecular target of sunitinib in EMC is unknown. Moreover, there is still the need to identify alternative therapeutic strategies. To better characterize this disease, we performed whole transcriptome sequencing in five EMC cases. Peculiarly, in one sample, an in-frame deletion (c.1735_1737delGAT p.D579del) was identified in exon 11 of KIT. The deletion was somatic and heterozygous and was validated both at DNA and mRNA level. This sample showed a marked high expression of KIT at the mRNA level and a mild phosphorylation of the receptor. Sanger sequencing of KIT in additional 15 Formalin Fixed Paraffin Embedded (FFPE) EMC did not show any other mutated cases. In conclusion, exon 11 KIT mutation was detected only in one out of 20 EMC cases analyzed, indicating that KIT alteration is not a recurrent event in these tumors and cannot explain the EMC sensitivity to sunitinib, although it is an actionable mutation in the individual case in which it has been identified