Occurrence fungi causing black foot on young grapevines and nursery rootstock plants in Italy

Summary. Young grapevine plants with decline and wood necrosis symptoms were collected from vineyards and nurseries in the Apulia and Molise regions, Italy, from 2013 to 2015. Isolations of fungi were prepared from 45 diseased grapevine plants, and the cultures were identified. Several species commonly associated with Petri disease, Botryosphaeria dieback, and black foot disease were isolated. A detailed study was carried out, and 182 isolates resembling Cylindrocarpon-like asexual forms were identified through morphological characterisation and DNA analysis of internal transcribed spacer regions 1 and 2 of the rRNA gene and the partial β-tubulin gene. Dactylonectria torrensensis and Ilyonectria liriodendri were identified based on morphological features and the partial histone 3 gene, so these fungi can be defined as the causal agents of black foot on grapevine for the first time in Italy. Thelonectria blackeriella is also described as a new species, through morphological characterisation and multigenic analysis using sequence data for five loci (large subunit RNA, internal transcribed spacers, β-tubulin, actin, RNA polymerase II subunit 1). This new species was associated with black foot symptoms according to preliminary pathogenicity tests, with representative isolates of each of the three species. Pathogenicity tests showed that these species can cause black streaking in the wood of 1-year-old grapevine rootstock shoots. The identification of D. torresensis, I. liriodendri and T. blackeriella from young grapevine plants and rooted rootstock highlights the importance of black foot disease in Italy, which has previously been overlooked

HPLC-HRMS global metabolomics approach for the diagnosis of "olive quick decline syndrome" markers in olive trees leaves

10openInternationalItalian coauthor/editorOlive quick decline syndrome (OQDS) is a multifactorial disease affecting olive plants. The onset of this economically devastating disease has been associated with a Gram-negative plant pathogen called Xylella fastidiosa (Xf). Liquid chromatography separation coupled to high-resolution mass spectrometry detection is one the most widely applied technologies in metabolomics, as it provides a blend of rapid, sensitive, and selective qualitative and quantitative analyses with the ability to identify metabolites. The purpose of this work is the development of a global metabolomics mass spectrometry assay able to identify OQDS molecular markers that could discriminate between healthy (HP) and infected (OP) olive tree leaves. Results obtained via multivariate analysis through an HPLC-ESI HRMS platform (LTQ-Orbitrap from Thermo Scientific) show a clear separation between HP and OP samples. Among the differentially expressed metabolites, 18 different organic compounds highly expressed in the OP group were annotated; results obtained by this metabolomic approach could be used as a fast and reliable method for the biochemical characterization of OQDS and to develop targeted MS approaches for OQDS detection by foliage analysisopenAsteggiano, A.; Franceschi, P.; Zorzi, M.; Aigotti, R.; Dal Bello, F.; Baldassarre, F.; Lops, F.; Carlucci, A.; Medana, C.; Ciccarella, G.Asteggiano, A.; Franceschi, P.; Zorzi, M.; Aigotti, R.; Dal Bello, F.; Baldassarre, F.; Lops, F.; Carlucci, A.; Medana, C.; Ciccarella, G

Management of Branched Broomrape in Field Processing Tomato Crop

In recent years, there has been a considerable increase in land area used for tomato (Lycopersicon esculentum Mill.) in many countries around the world. The essential role is played by Italy at a worldwide level as the country with the third biggest production of tomatoes for processing. Phelipanche ramosa (L) Pomel, commonly known as branched broomrape, is a root holoparasitic weed for many crops, particularly for the processing tomato. Due to its physical and metabolic overlap with the crop, its underground parasitism, and hardly destructible seed bank, the control of this parasite in the field is difficult. Results of research studies, many of them on environmental-friendly methods such as preventive, agronomic, and biological carried out in southern Italy, are discussed and summarized. The results can constitute a relevant basis for further experimental studies

A real time loop-mediated isothermal amplification (RealAmp) assay for rapid detection of Pleurostoma richardsiae in declining olive plants

Pleurostoma richardsiae is associated with host trunk diseases, known to cause dieback, cankers and wilting of woody trees, and human infections. This fungus was isolated from wood tissues of declining olive trees and grapevines showing esca disease symptoms, in the Apulia region of Italy. Fungus detection has been based on morphological and molecular features, which are time-consuming to identify and require well-trained personnel. Improvement of Pl. richardsiae detection in olive was achieved through development of real time loop-mediated isothermal amplification targeting the intergenic spacer (IGS) region of the fungus. Specificity of the assay was confirmed using ten Pl. richardsiae strains and 36 other fungus strains of species usually isolated from declining olive trees. The achieved limit of detection was 7.5 × 10-2 ng μL-1 of Pl. richardsiae genomic DNA. A preliminary validation of RealAmp was also performed using material from infected olive plants artificially inoculated in a greenhouse

Mitigation and adaptation to climate change of plant pathogens

The impact of climate change on plant diseases poses a serious threat to food security [1-4]. Climate change has a direct effect on the occurrence and severity of disease in crops. Global plant health assessment and crop loss estimation due to pests and diseases has been made especially for cropping regions defined by the major crops of wheat, rice, maize, potato and soybean [5]

Vegeto-productive behaviour and fruit quality of two cultivars of apricot, ‘Orange Rubis®’ and ‘Farbaly®’, as influenced by different biostimulants

Agricultural biostimulants (ABs), products with specific action, natural or synthetic, mineral or organic, have been introduced recently as fertilizers that are applied in small quantities in order to increase nutrient uptake, growth and development of plants and improve quality, productivity, crop resistance and the environmental positive impacts. This trial aims to evaluate the effect of four different commercial ABs (Bion® 50 WG, Hendophit® PS, Ergostim® and Radicon®) on two cultivars of apricot (‘Orange Rubis®’ and ‘Farbaly®’), grown in experimental field at Cerignola (Foggia district, Apulian region, southern Italy). The biostimulants used were related products of humic acids that induce effects on yield, fruit quality and grower income of some fruit trees. Several foliar treatments were applied at different times during the growth season of each crop. Total yield of fruits tree-1 was also determined. Other than that related with vegeto-productive behaviour, many fruit quality parameters were evaluated, including also total polyphenols content and antioxidant activity. Experimental data showed some specific differences among the biostimulant treatments. Growth was not affected while productivity was only moderately affected in one of the two cultivars and not always positively. Main influences were found regarding qualitative attributes of fruits. The soluble solids content in ‘Farbaly’ was clearly positively affected by Bion® and Hendophyt® treatments while no effect of ABs was observed in ‘Orange Rubis’. Results suggest that effects of ABs are ‘genotype dependent’ and that probably doses and scheduling of ABs application should be precisely defined in each agricultural context

Vegeto-Productive Behavior and Fruit Quality of Two Cultivars of Apricot, 'Orange rubis®' and 'Farbaly®', as Influenced by Different Biostimulants

Agricultural biostimulants (ABs), products with specific action, natural or synthetic, mineral or organic, have been introduced recently as fertilizers that are applied in small quantities in order to increase nutrient uptake, growth and development of plants and improve quality, productivity, crop resistance and the environmental positive impacts. This trial aims to evaluate the effect of four different commercial ABs (Bion® 50 WG, Hendophit® PS, Ergostim® and Radicon®) on two cultivars of apricot (‘Orange rubis®’ and ‘Farbaly®’), grown in experimental field at Cerignola (Foggia district, Apulian region, Southern Italy). The biostimulants used were related products of humic acids that induce effects on yield, fruit quality and grower income of some fruit trees. Several foliar treatments were applied at different time during the growth season of each crops. Total yield of fruits per tree was also determined. Other than that related with vegeto-productive behavior, many fruit quality parameters were evaluated, including also total polyphenols content and antioxidant activity. Experimental data showed some specific differences among the biostimulant treatments. Growth was not affected while productivity was only moderately affected in one of the two cultivars and not always positively. Main influenced were found regarding qualitative attributes of fruits. The soluble solids content in ‘Farbaly’ was clearly positively affected by Bion® and Hendophyt® treatments while no effect of ABs was observed in ‘Orange Rubis’. Results suggest that effects of ABs is ‘genotype dependent’ and that probably doses and scheduling of ABs application should be precisely defined in each agricultural context

First Report of Phaeoacremonium oleae and P. viticola Associated with Olive Trunk Diseases in Italy

Over 300 trunk, branch, and stem samples with vascular discoloration, necrotic wood, and shoot death were collected from olive (Olea europaea) orchards in Lecce, Brindisi, Bari, and Foggia provinces (Apulia region, Italy) from October to May from 2013 to 2019. Small chips of symptomatic wood samples were surface sterilized (5% NaOCl, 3 min; 70% ethanol, 30 s), rinsed (sterile distilled water, ×3), and placed onto potato dextrose agar (PDA) plates amended with 500 ppm of streptomycin sulfate. After 14 days at 25°C in the dark, hyphal tips of growing fungi, including different taxa, for instance Phaeoacremonium and Botryosphaeriaceae spp., were transferred to new PDA plates and incubated until sporulation. Monoclonal colonies resembling Phaeoacremonium-like genus (Mostert et al. 2006) were selected for further study, and genomic DNA of 59 representative isolates was extracted (Carlucci et al. 2013). Partial actin and β-tubulin genes were amplified with primers ACT-512F/ACT-783R (Carbone and Kohn 1999), and T1 (O’Donnell and Cigelnik 1997) and Bt2b (Glass and Donaldson 1995), respectively. The sequenced amplicons were compared by BLAST algorithms with reference strains of Phaeoacremonium spp. retrieved from GenBank. Forty-four isolates showed 99 to 100% similarity with reference strains P. italicum, P. minimum, P. parasiticum, P. scolyti, and P. sicilianum (Carlucci et al. 2015), nine with P. oleae, and six with P. viticola. Actin and β-tubulin sequences of P. oleae (Pm14) and P. viticola (Pm34) were submitted to GenBank (MW714561, MW714563; MZ318697, MZ318696). Microscopy of P. oleae isolates showed the following: conidiophores branched and unbranched, (18.7 to) 21.9 to 57.1 (to 67.8) × (2.9 to) 3.3 to 4.7 (to 5.2) (mean, 38.9 × 4.1) μm (n = 30); conidia oblong-ellipsoidal to obovoid or subcylindrical, 3.4 to 5.5 μm long, and 1.5 to 2.4 (mean, 4.6 × 2.2) μm wide (n = 30). Microscopy of P. viticola isolates showed the following: conidiophores subcylindrical, branched at base (6.7 to) 8.9 to 27.2 (to 29.3) × (2.0 to) 2.6 to 3.3 (to 3.7) (mean, 21.4 × 3.2) μm (n = 30); conidia oblong-ellipsoidal to obovoid or subcylindrical, 3.3 to 6.8 μm long, and 1.1 to 2.2 (mean, 4.2 × 1.6) μm wide (n = 30). In spring 2020, artificial inoculations were carried out with P. oleae (Pm14, Pm46) and P. viticola (Pm34, Pm43) strains on 10 healthy, 2-year-old olive seedlings of cultivar ‘Coratina’. Agar plugs (diameter, 0.3 to 0.5 cm) from 10-day-old cultures grown on water agar at 23 ± 2°C were inserted under the bark of small wounds in the stems (length, 0.4 to 1.0 cm) made with a sterile scalpel. After inoculation, the wounds were wrapped with wet sterile cotton wool and sealed with Parafilm. Ten control olive seedlings were inoculated with sterile agar plugs. The experiment was replicated three times. All inoculated young olive plants were grown in pots in a greenhouse without temperature control. After 120 days, inoculated plants showed decline symptoms, and when cut longitudinally, brown streaks were observed in the wood. For P. oleae these streaks measured 3.0 to 5.5 cm long (standard deviation [SD], 0.9 cm), and for P. viticola they were 1.8 to 3.5 cm (SD, 0.62 cm). Both fungal species were reisolated from the symptomatic wood from 85 and 80%, respectively, of these inoculated olive seedlings, fulfilling Koch’s postulates. No symptoms were observed from olive seedlings used as control. P. oleae was first described as a fungal pathogen of wild olive (O. europaea subsp. cuspidata) in South Africa by Spies et al. (2018) and P. viticola as a fungal pathogen of grapevine in France by Dupont et al. (2000). To the best of our knowledge, this is the first report of P. oleae associated with olive trunk disease in Italy and the first report of P. viticola associated with olive trunk disease worldwide