Maria Luisa Raimondo

Phaeoacremonium species associated with olive wilt and decline in southern Italy

Six Phaeoacremonium species (spp.) were isolated from symptomatic wood of olive trees (Olea europea) in Apulia (southern Italy) that showed crown wilt and twig and branch dieback. These Phaeoacremonium spp. were identified according to their morphological characteristics and by analyses of partial sequences of the actin and β-tubulin genes. Combining these cultural, morphological and molecular data, three Phaeoacremonium spp. were isolated that are already known to be responsible for severe decline of olive in Apulia, Phaeoacremonium aleophilum, Phaeoacremonium alvesii and Phaeoacremonium parasiticum, together with three other Phaeoacremonium spp. that are associated for the first time with wilt, decline and dieback of olive orchards in Italy and worldwide: Phaeoacremonium italicum, Phaeoacremonium sicilianum and Phaeoacremonium scolyti. To understand and to confirm their involvement in wilt and decline of olive trees, pathogenicity assays were performed on shoots of young olive plants. The data indicate that all six of these Phaeoacremonium spp. can cause discolouration, necrotic wood, and death of shoots, although different levels of virulence were observed, with Pm. italicum, Pm. aleophilum and Pm. sicilianum producing greater necrotic lesions than the other Phaeoacremonium spp. investigated here.

Phaeoacremonium italicum sp. nov., associated with esca of grapevine in southern Italy

To date at least 42 Phaeoacremonium species are known throughout the world. These fungal pathogens are responsible for several syndromes that occur in wood of different hosts, 27 of which have been associated with decline and dieback diseases or esca of grapevine and have been abundantly isolated from necrotic wood of grapevines with Petri and esca disease in vineyards worldwide. During a survey carried out in five vineyards of the grapevine cultivar Italia, several symptomatic samples were collected. A collection of 28 Phaeoacremonium isolates was analyzed. The phylogenetic relationships of the isolates were determined through the study of the β-tubulin and actin gene sequences. Combining morphological, culture and molecular data, three known Phaeoacremonium spp. were found, namely Pm. aleophilum, Pm. parasiticum and Pm. scolyti. One new species is described. Phaeoacremonium italicum can be identified by the common occurrence of bundles of up to 13, conidiophores with up to seven septa, occasionally branched, percurrent rejuvenation and predominantly phialides of type II. This novel species thus is isolated for the first time from grapevine in Apulia (southern Italy).

Fungal bioremediation of olive mill wastewater: Using a multi-step approach to model inhibition or stimulation.

BACKGROUND Olive mill wastewaters (OMWWs) possess a strong environmental impact; the use of fungi as tools for bioremediation could be a promising method. RESULTS Twenty-nine fungi were grown on minimal media supplemented with five different kinds of OMWWs (5-15%). Radial growth was assessed for 21 days and the data were modelled through the Dantigny-logistic like function to estimate τ, i.e. the time to attain half of the maximum diameter. Growth on potato dextrose agar and water agar (WA, minimal medium without supplementation) was used as reference. The differences in τ between PDA/WA and minimal media with OMWWs were modelled through a multi-factorial ANOVA, using the concentration of OMWW, the kind of wastes and fungi as categorical predictors. Finally, a principal component analysis was run to group and divide resistant and sensitive fungi. Some fungi experienced a positive Δτ, thus suggesting an inhibition by OMWW, whereas other isolates were enhanced. CONCLUSIONS Some isolates (for example Aspergillus ochraceus) showed a promising trend and could be possible candidates for a validation on a real scale.

First report of stem wilt and root rot of Schlumbergera truncata caused by Fusarium oxysporum f. sp. Opuntiarum in southern Italy.

Schlumbergera truncata (Haw.) Moran, belonging to the Cactaceae, is a very common ornamental cactus in southern Italy. In November 2011, sudden stem wilt and root rot was observed in about 45% of vegetatively propagated plants cultivated as potted ornamental plants in a commercial greenhouse in Cerignola (Foggia Province, Apulia, Italy). The roots and collars of the plants showed brown rot. Yellow sunken lesions that were similar to cortical cankers were detected at basal level of the stem. Ten plants with these symptoms were analyzed by fungal isolation techniques. Small (0.5 cm) tissue portions from root, collar, and basal stem were plated on potato dextrose agar (PDA) after disinfection with 75% ethanol for 1 to 2 min, 0.2% NaOCl for 1 to 2 min, and a wash with sterile distilled water. A fungal isolate that was morphologically similar to Fusarium sp. was isolated from 85% of these tissue samples. It had nucleotide sequences of the internal transcribed spacer region (ITS1-5.8S-ITS2) of ribosomal DNA (GenBank Accession No. KC196121) 100% identical to those of the comparable sequences of Fusarium oxysporum (HQ651161). The nucleotide sequences of its translation elongation factor 1-α (EF-1α) gene (KC196120) showed 100% identity to sequences of F. oxysporum f. sp. opuntiarum (DQ837689, AF246881) retrieved from GenBank. Pathogenicity tests were performed at 22 ± 3°C on 18 45-day-old plants of S. truncate by adding of a 5-ml aliquot of conidial suspension adjusted to 5 × 106 conidia/ml to soil of each plant. Six non-inoculated plants were used for a control treatment and sprayed with 5 ml of sterilized water. Plants were maintained in greenhouse at 22 ± 3°C. After 10 days, nine of the inoculated plants showed wilting, and after 45 days, all of them were dead, with root and collar rot and lesions on the basal stem. Control plants were symptomless. Kochs postulates were fulfilled as the pathogen was reisolated from all of the symptomatic tissues and identified as Fusarium sp. On the basis of 3-septate macroconidia (mean 31.75 × 3.21 μm; range, 26 to 35 μm long, 3.0 to 4.2 μm wide), aseptate microconidia, single chlamydospores, and monophialide conidiophores on carnation leaf agar, and molecular analyses, the fungus was identified as F. oxysporum f. sp. opuntiarum (Speg) (1,2,3). In Italy, F. oxysporum f. sp. opuntiarum was reported as basal stem rot of Echinocactus grusoni (4). To our knowledge, this is the first report of stem wilt and root rot of S. truncata caused by F. oxysporum f. sp. opuntiarum in Italy. References: (1) W. Gerlach. Phytopathol. Z. 74:197, 1972. (2) W. L. Gordon. Can. J. Bot. 43:1309, 1965. (3) P. E. Nelson et al. Fusarium Species: An Illustrated Manual for Identification. Pennsylvania State University Press, University Park, 1983. (4) G. Polizzi et al. Plant Dis. 88:85, 2004.

Pathogenicity assessment of different Plectosphaerella species on basil, pepper and tomato crops in southern Italy

A and semiarid areas has a hydrological rainfall pattern characterized by variability, intense rainfall, as the rainfall volumes are concentrated into short periods of time with widely varying temporal recurrence of rainfall events consequently, high peak flows occurred. In most of Brazil semiarid he conventional soil management still is burning for the establishment crops. In this soil use, the natural resources are under risk and prone to degradation. In this conditions the soil use capacity of semiarid watersheds is soon exceeded due to soil cover of shrub decrease. The major degradation sign is the water erosion that generates the sediment through interrill, rill and gully erosion. The fluvial systems of arid and semiarid environments are featured by periods without flow, and the suspended sediment transport can occur in high suspended sediment concentration values in ascending hydrograph, which are associated with the sediment in the entrainment threshold that deposited in the preceding year. In this context, we are developing a project in a small watershed with 14.71 km2 (Carnauba Watershed from Brazilian semiarid) in which the farmers are seeding corn, beans and cactus without burn residues to prepare the soil through environmental compensation, as a mitigation to climate changes. In this project are included 10 farmers during two years in the Carnauba watershed, in which the flow and suspended sediment are been monitoring, and in the project end it will be expect to observe decrease in suspended sediment flux.T influence of organic matter vis-a-vis humic acids on the availability of nutrient status and its impact on the cultivation of rice (Variety MTU 1010) followed by mustard (Variety B-9), was studied in Typic Fluvaquent soil under Old Alluvial zone of West Bengal, India. Soil texture was identified as sandy clay loam, bulk density 1.34 Mg m-3, oxidizable OC 1.16 g 100gm-1, pH 6.34, total nitrogen 0.14 g 100gm-1, available phosphate, potash and sulphate 25.90, 127.40, 39.56 kg ha-1, respectively. Soils received recommended doses of fertilizers for cultivation of paddy (N:P2O5:K2O::60:30:30) followed by mustard (N:P2O5:K2O::80:40:40) along with FYM at 5.0 and 2.5 t ha-1, both Commercial and FYM extracted humic acid (CHA & EHA) at 0.5, 0.25 kg ha-1, respectively as per treatment combinations and following RBD treatment. Rhizosphere soil (0-15 cm) and plant samples were periodically collected and analysed for C:N ratio, available phosphate, potash and sulphur with their integral effect on crop growth. At PI and branching stages of paddy and mustard, the highest content of available phosphate, potash and sulphur was recorded and gradually decreasd towards harvesting stage. EHA resulted highest availability of phosphate and sulphur, however CHA enhanced the content of potash in soil, resulted significant uptake of nutrients within plants and qualitative enrichment through biometric parameters and yield.The aim of this study was evaluation of the effect of aging germination and activity of antioxidant enzymes in seeds of Allium cepa L. and Brassica oleracea var capitata with seed priming treatment. In the present paper the different seaweed extract from Ulva lactuca L. (G1), U. reticulata forsskal (G2), Padina pavonica L. (B3), Sargassum johnstonii Setchell & Gardner (B4), Kappaphycus alvarezii (R5) and Gracillaria corticata J. Ag. (R6) was applied as seed priming and performed prior to accelerated ageing treatment with the investigation of activities of catalase (CAT) and peroxidase (POD) during accelerated aging. Our result indicates that to enhance germination characteristics in aged seeds with priming treatment also reveals positive effect of seed priming on the germination percentage, vigour index, seedling length and antioxidant activity of enzyme. The highest germination percentage, vigour index, seedling length and enzyme activity were achieved in given priming treatment with aging (12 day of aging) as compared to control condition (0 day of aging).Methodology & Theoretical Orientation: In this study, an attempt has been made to characterize a novel bi-directional promoter from the Indian cassava mosaic virus (ICMV, family: Geminiviridae) by both transient and transgenic assays to satisfy such demands. We have made several sequential deletion constructs of the bidirectional promoter of ICMV, both in the viral-sense orientation (driving the expression of AV1/ coat protein and AV2; the CP-promoter) and in the complementary-sense orientation (driving the expression of Replication associated protein and other 3 ORFs; the Rep-promoter). The deletion-constructs, two for each of these promoters were made in pBI121 binary vector driving the expression of the Gus gene; care was taken not to delete key motifs such as TATA box (using PlantCARE analysis). Transient as well as transgenic expression was assayed.

Evaluation of Fungal Growth on Olive-Mill Wastewaters Treated at High Temperature and by High-Pressure Homogenization

Reuse of olive mill wastewaters (OMWWs) in agriculture represents a significant challenge for health and safety of our planet. Phytotoxic compounds in OMWW generally prohibit use of untreated OMWWs for agricultural irrigation or direct discharge into surface waters. However, pretreated OMWW can have positive effects on chemical and microbiological soil characteristics, to fight against fungal soil-borne pathogens. Low amounts of OMWW following thermal (TT-OMWW) and high-pressure homogenization (HPH-OMWW) pretreatments counteracted growth of some of 12 soil-borne and/or pathogenic fungi examined. With fungal growth measured as standardized change in time to half maximum colony diameter, Δτ, overall, HPH-OMWW showed increased bioactivity, as increased mean Δτ from 3.0 to 4.8 days. Principal component analysis highlighted two fungal groups: Colletotrichum gloeosporioides, Alternaria alternata, Sclerotium rolfsii, and Rosellinia necatrix, with growth strongly inhibited by the treated OMWWs; and Aspergillus ochraceus and Phaeoacremonium parasiticum, with stimulated growth by the treated OMWWs. As a non-thermal treatment, HPH-OMWW generally shows improved positive effects, which potentially arise from preservation of the phenols.

Charcoal Canker of Pear, Plum, and Quince Trees Caused by Biscogniauxia rosacearum sp. nov. in Southern Italy

The genus Biscogniauxia is paraphyletic to members of the family Xylariaceae and includes at least 52 species to date that are mainly pathogens of dicotyledonous angiosperm trees. Most of these are forest trees, such as those in the genera Acacia, Acer, Alnus, Eucalyptus, Fraxinus, Populus, and Quercus, and other species of minor importance. Biscogniauxia spp. have been reported as endophytes or secondary invaders that attack only stressed plants. During a survey in rosaceous orchards in southern Italy, several charcoal cankers were observed and stroma samples were collected. A collection of 31 Biscogniauxia isolates was analyzed. Their phylogenetic relationships were determined through study of the internal transcribed spacer, β-tubulin, and actin gene sequences. Combining morphological, cultural, and molecular data, a new species of Biscogniauxia is described here as Biscogniauxia rosacearum. This new species was isolated for the first time from rosaceous hosts in Apulia. Pathogenicity tests showed that it causes symptoms on stems when artificially inoculated and produces stromata on the bark surface.