The Xylella fastidiosa-Resistant Olive Cultivar “Leccino” Has Stable Endophytic Microbiota during the Olive Quick Decline Syndrome (OQDS)

Xylella fastidiosa is a highly virulent pathogen that causes Olive Quick Decline Syndrome (OQDS), which is currently devastating olive plantations in the Salento region (Apulia, Southern Italy). We explored the microbiome associated with X. fastidiosa-infected (Xf-infected) and -uninfected (Xf-uninfected) olive trees in Salento, to assess the level of dysbiosis and to get first insights into the potential role of microbial endophytes in protecting the host from the disease. The resistant cultivar “Leccino” was compared to the susceptible cultivar “Cellina di Nardò”, in order to identify microbial taxa and parameters potentially involved in resistance mechanisms. Metabarcoding of 16S rRNA genes and fungal ITS2 was used to characterize both total and endophytic microbiota in olive branches and leaves. “Cellina di Nardò” showed a drastic dysbiosis after X. fastidiosa infection, while “Leccino” (both infected and uninfected) maintained a similar microbiota. The genus Pseudomonas dominated all “Leccino” and Xf-uninfected “Cellina di Nardò” trees, whereas Ammoniphilus prevailed in Xf-infected “Cellina di Nardò”. Diversity of microbiota in Xf-uninfected “Leccino” was higher than in Xf-uninfected “Cellina di Nardò”. Several bacterial taxa specifically associated with “Leccino” showed potential interactions with X. fastidiosa. The maintenance of a healthy microbiota with higher diversity and the presence of cultivar-specific microbes might support the resistance of “Leccino” to X. fastidiosa. Such beneficial bacteria might be isolated in the future for biological treatment of the OQDS.

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HPLC-MS/MS method applied to an untargeted metabolomics approach for the diagnosis of “olive quick decline syndrome”

Analytical and Bioanalytical Chemistry ◽

10.1007/s00216-021-03279-7 ◽

2021 ◽

Author(s):

Sabrina Di Masi ◽

Giuseppe E. De Benedetto ◽

Cosimino Malitesta ◽

Maria Saponari ◽

Cinzia Citti ◽

...

Keyword(s):

Bacterial Infections ◽

High Performance ◽

High Resolution Mass Spectrometry ◽

Xylella Fastidiosa ◽

Long Chain Fatty Acids ◽

Powerful Approach ◽

Diffusible Signal Factor ◽

Profile Changes ◽

Olive Quick Decline Syndrome ◽

Olive Trees

AbstractOlive quick decline syndrome (OQDS) is a disorder associated with bacterial infections caused by Xylella fastidiosa subsp. pauca ST53 in olive trees. Metabolic profile changes occurring in infected olive trees are still poorly investigated, but have the potential to unravel reliable biomarkers to be exploited for early diagnosis of infections. In this study, an untargeted metabolomic method using high-performance liquid chromatography coupled to quadrupole-time-of-flight high-resolution mass spectrometry (HPLC-ESI-Q-TOF-MS) was used to detect differences in samples (leaves) from healthy (Ctrl) and infected (Xf) olive trees. Both unsupervised and supervised data analysis clearly differentiated the groups. Different metabolites have been identified as potential specific biomarkers, and their characterization strongly suggests that metabolism of flavonoids and long-chain fatty acids is perturbed in Xf samples. In particular, a decrease in the defence capabilities of the host after Xf infection is proposed because of a significant dysregulation of some metabolites belonging to flavonoid family. Moreover, oleic acid is confirmed as a putative diffusible signal factor (DSF). This study provides new insights into the host-pathogen interactions and confirms LC-HRMS-based metabolomics as a powerful approach for disease-associated biomarkers discovery in plants. Graphical abstract

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Role of Broiler Carcasses and Processing Plant Air in Contamination of Modified-Atmosphere-Packaged Broiler Products with Psychrotrophic Lactic Acid Bacteria

Applied and Environmental Microbiology ◽

10.1128/aem.01644-06 ◽

2006 ◽

Vol 73 (4) ◽

pp. 1136-1145 ◽

Cited By ~ 55

Author(s):

Elina Vihavainen ◽

Hanna-Saara Lundstrï¿½m ◽

Tuija Susiluoto ◽

Joanna Koort ◽

Lars Paulin ◽

...

Keyword(s):

Lactic Acid ◽

Lactic Acid Bacteria ◽

16S Rrna Genes ◽

Rrna Genes ◽

23S Rrna ◽

Processing Plant ◽

Modified Atmosphere ◽

Production Plant ◽

Meat Spoilage

ABSTRACT Some psychrotrophic lactic acid bacteria (LAB) are specific meat spoilage organisms in modified-atmosphere-packaged (MAP), cold-stored meat products. To determine if incoming broilers or the production plant environment is a source of spoilage LAB, a total of 86, 122, and 447 LAB isolates from broiler carcasses, production plant air, and MAP broiler products, respectively, were characterized using a library of HindIII restriction fragment length polymorphism (RFLP) patterns of the 16 and 23S rRNA genes as operational taxonomic units in numerical analyses. Six hundred thirteen LAB isolates from the total of 655 clustered in 29 groups considered to be species specific. Sixty-four percent of product isolates clustered either with Carnobacterium divergens or with Carnobacterium maltaromaticum type strains. The third major product-associated cluster (17% of isolates) was formed by unknown LAB. Representative strains from these three clusters were analyzed for the phylogeny of their 16S rRNA genes. This analysis verified that the two largest RFLP clusters consisted of carnobacteria and showed that the unknown LAB group consisted of Lactococcus spp. No product-associated LAB were detected in broiler carcasses sampled at the beginning of slaughter, whereas carnobacteria and lactococci, along with some other specific meat spoilage LAB, were recovered from processing plant air at many sites. This study reveals that incoming broiler chickens are not major sources of psychrotrophic spoilage LAB, whereas the detection of these organisms from the air of the processing environment highlights the role of processing facilities as sources of LAB contamination.

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Coaggregation among Nonflocculating Bacteria Isolated from Activated Sludge

Applied and Environmental Microbiology ◽

10.1128/aem.69.10.6056-6063.2003 ◽

2003 ◽

Vol 69 (10) ◽

pp. 6056-6063 ◽

Cited By ~ 91

Author(s):

Anushree Malik ◽

Masashi Sakamoto ◽

Shohei Hanazaki ◽

Masamitsu Osawa ◽

Takanori Suzuki ◽

...

Keyword(s):

16S Rrna ◽

Activated Sludge ◽

Aggregate Size ◽

Spectrophotometric Assay ◽

Full Length ◽

16S Rrna Genes ◽

Rrna Genes ◽

Acinetobacter Junii ◽

Acinetobacter Johnsonii

ABSTRACT Thirty-two strains of nonflocculating bacteria isolated from sewage-activated sludge were tested by a spectrophotometric assay for their ability to coaggregate with one other in two-membered systems. Among these strains, eight showed significant (74 to 99%) coaggregation with Acinetobacter johnsonii S35 while only four strains coaggregated, to a lesser extent (43 to 65%), with Acinetobacter junii S33. The extent and pattern of coaggregation as well as the aggregate size showed good correlation with cellular characteristics of the coaggregating partners. These strains were identified by sequencing of full-length 16S rRNA genes. A. johnsonii S35 could coaggregate with strains of several genera, such as Oligotropha carboxidovorans, Microbacterium esteraromaticum, and Xanthomonas spp. The role of Acinetobacter isolates as bridging organisms in multigeneric coaggregates is indicated. This investigation revealed the role of much-neglected nonflocculating bacteria in floc formation in activated sludge.

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Increase in ring width, vessel number and δ18O in olive trees infected with Xylella fastidiosa

Tree Physiology ◽

10.1093/treephys/tpaa095 ◽

2020 ◽

Vol 40 (11) ◽

pp. 1583-1594

Author(s):

Erika Sabella ◽

Samuele Moretti ◽

Holger Gärtner ◽

Andrea Luvisi ◽

Luigi De Bellis ◽

...

Keyword(s):

Xylella Fastidiosa ◽

Ring Width ◽

Plant Diseases ◽

Susceptible Cultivar ◽

Water Conductivity ◽

Leaf Transpiration ◽

Leaf Level ◽

Olive Quick Decline Syndrome ◽

Olive Trees ◽

Tree Stem

Abstract Xylella fastidiosa (Xf) Wells, Raju et al., 1986 is a bacterium that causes plant diseases in the Americas. In Europe, it was first detected on the Salento Peninsula (Italy), where it was found to be associated with the olive quick decline syndrome. Here, we present the results of the first tree-ring study of infected and uninfected olive trees (Olea europaea L.) of two different cultivars, one resistant and one susceptible, to establish the effects induced by the spread of the pathogen inside the tree. Changes in wood anatomical characteristics, such as an increase in the number of vessels and in ring width, were observed in the infected plants of both the cultivars Cellina di Nardò (susceptible to Xf infection) and Leccino (resistant to Xf infection). Thus, whether infection affects the mortality of the tree or not, the tree shows a reaction to it. The presence of occlusions was detected in the wood of both 4-year-old branches and the tree stem core. As expected, the percentage of occluded vessels in the Xf-susceptible cultivar Cellina di Nardò was significantly higher than in the Xf-resistant cultivar Leccino. The δ 18O of the 4-year-old branches was significantly higher in infected trees of both cultivars than in noninfected trees, while no variations in δ 13C were observed. This suggests a reduction in leaf transpiration rates during infection and seems to be related to the occlusions observed in rings of the 4-year-old branches. Such occlusions can determine effects at leaf level that could influence stomatal activity. On the other hand, the significant increase in the number of vessels in infected trees could be related to the tree’s attempt to enhance water conductivity in response to the pathogen-induced vessel occlusions.

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Aphrophoridae Role in Xylella fastidiosa subsp. pauca ST53 Invasion in Southern Italy

Pathogens ◽

10.3390/pathogens10081035 ◽

2021 ◽

Vol 10 (8) ◽

pp. 1035

Author(s):

Ugo Picciotti ◽

Nada Lahbib ◽

Valdete Sefa ◽

Francesco Porcelli ◽

Francesca Garganese

Keyword(s):

Pest Management ◽

Plant Pathogen ◽

Southern Italy ◽

Xylella Fastidiosa ◽

Xylem Sap ◽

Disease Spread ◽

Insect Vector ◽

Transmission Control ◽

Olive Quick Decline Syndrome ◽

Olive Trees

The Philaenus spumarius L. (Hemiptera Aphrophoridae) is a xylem-sap feeder vector that acquires Xylella fastidiosa subsp. pauca ST53 during feeding on infected plants. The bacterium is the plant pathogen responsible for olive quick decline syndrome that has decimated olive trees in Southern Italy. Damage originates mainly from the insect vector attitude that multiplies the pathogen potentialities propagating Xf in time and space. The principal action to manage insect-borne pathogens and to contain the disease spread consists in vector and transmission control. The analysis of an innovative and sustainable integrated pest management quantitative strategy that targets the vector and the infection by combining chemical and physical control means demonstrates that it is possible to stop the Xylella invasion. This review updates the available topics addressing vectors’ identification, bionomics, infection management, and induced disease by Xylella invasion to discuss major available tools to mitigate the damage consequent to the disease.

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Investigation of Sources, Diversity, and Variability of Bacterial Aerosols in Athens, Greece: A Pilot Study

Atmosphere ◽

10.3390/atmos13010045 ◽

2021 ◽

Vol 13 (1) ◽

pp. 45

Author(s):

Angelina Metaxatos ◽

Sydonia Manibusan ◽

Gediminas Mainelis

Keyword(s):

Field Application ◽

16S Rrna Genes ◽

Rrna Genes ◽

Airborne Bacteria ◽

Urban Air ◽

Operational Taxonomic Units ◽

Bacterial Aerosol ◽

Bacterial Aerosols ◽

Taxonomic Categories

We characterized the composition, diversity, and potential bacterial aerosol sources in Athens’ urban air by DNA barcoding (analysis of 16S rRNA genes) during three seasons in 2019. Air samples were collected using the recently developed Rutgers Electrostatic Passive Sampler (REPS). It is the first field application of REPS to study bacterial aerosol diversity. REPS samplers captured a sufficient amount of biological material to demonstrate the diversity of airborne bacteria and their variability over time. Overall, in the air of Athens, we detected 793 operational taxonomic units (OTUs), which were fully classified into the six distinct taxonomic categories (Phylum, Class, Order, etc.). These OTUs belonged to Phyla Actinobacteria, Firmicutes, Proteobacteria, Bacteroidetes, Cyanobacteria, and Fusobacteria. We found a complex community of bacterial aerosols with several opportunistic or potential pathogens in Athens’ urban air. Referring to the available literature, we discuss the likely sources of observed airborne bacteria, including soil, plants, animals, and humans. Our results on bacterial diversity are comparable to earlier studies, even though the sampling sites are different or geographically distant. However, the exact functional and ecological role of bioaerosols and, even more importantly, their impact on public health and the ecosystem requires further air monitoring and analysis.

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Ionomic Differences between Susceptible and Resistant Olive Cultivars Infected by Xylella fastidiosa in the Outbreak Area of Salento, Italy

Pathogens ◽

10.3390/pathogens8040272 ◽

2019 ◽

Vol 8 (4) ◽

pp. 272 ◽

Cited By ~ 10

Author(s):

Giusy D’Attoma ◽

Massimiliano Morelli ◽

Pasquale Saldarelli ◽

Maria Saponari ◽

Annalisa Giampetruzzi ◽

...

Keyword(s):

Inductively Coupled Plasma ◽

Xylella Fastidiosa ◽

Optical Emission ◽

Host Genotype ◽

Bacterial Populations ◽

Inductively Coupled ◽

Outbreak Area ◽

Olive Cultivars ◽

Olive Quick Decline Syndrome ◽

Olive Trees

Olive quick decline syndrome (OQDS) is a devastating disease of olive trees in the Salento region, Italy. This disease is caused by the bacterium Xylella fastidiosa, which is widespread in the outbreak area; however, the “Leccino” variety of olives has proven to be resistant with fewer symptoms and lower bacterial populations than the “Ogliarola salentina” variety. We completed an empirical study to determine the mineral and trace element contents (viz; ionome) of leaves from infected trees comparing the two varieties, to develop hypotheses related to the resistance of Leccino trees to X. fastidiosa infection. All samples from both cultivars tested were infected by X. fastidiosa, even if leaves were asymptomatic at the time of collection, due to the high disease pressure in the outbreak area and the long incubation period of this disease. Leaves were binned for the analysis by variety, field location, and infected symptomatic and infected asymptomatic status by visual inspection. The ionome of leaf samples was determined using inductively coupled plasma optical emission spectroscopy (ICP-OES) and compared with each other. These analyses showed that Leccino variety consistently contained higher manganese (Mn) levels compared with Ogliarola salentina, and these levels were higher in both infected asymptomatic and infected symptomatic leaves. Infected asymptomatic and infected symptomatic leaves within a host genotype also showed differences in the ionome, particularly a higher concentration of calcium (Ca) and Mn levels in the Leccino cultivar, and sodium (Na) in both varieties. We hypothesize that the ionome differences in the two varieties contribute to protection against disease caused by X. fastidiosa infection.

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Transmission of Xylella fastidiosa Subspecies Pauca Sequence Type 53 by Different Insect Species

Insects ◽

10.3390/insects10100324 ◽

2019 ◽

Vol 10 (10) ◽

pp. 324 ◽

Cited By ~ 17

Author(s):

Vincenzo Cavalieri ◽

Giuseppe Altamura ◽

Giulio Fumarola ◽

Michele di Carolo ◽

Maria Saponari ◽

...

Keyword(s):

Xylella Fastidiosa ◽

Severe Disease ◽

Xylem Sap ◽

Seasonal Abundance ◽

Philaenus Spumarius ◽

Olive Groves ◽

Sap Feeding ◽

Olive Quick Decline Syndrome ◽

Exotic Pathogen

Diseases associated with Xylella fastidiosa have been described mostly in North and South America. However, during the last five years, widespread X. fastidiosa infections have been reported in a constrained area of the Apulia region (southern Italy), in olives trees suffering a severe disease, denoted as Olive Quick Decline Syndrome (OQDS). Because many xylem sap-feeding insects can function as vectors for the transmission of this exotic pathogen in EU, several research programs are ongoing to assess the role of candidate vectors in the spread of the infections. Initial investigations identified Philaenus spumarius (L.) as the predominant vector species in the olive orchards affected by the OQDS. Additional experiments have been carried out during 2016 and 2017 to assess the role of other species. More specifically, adults of the spittlebugs Philaenus italosignus Drosopolous and Remane, Neophilaenus campestris (Fallen) and of the planthopper Latilica tunetana (Matsumura) (Issidae) have been tested in transmission experiments to assess their ability to acquire the bacterium from infected olives and to infect different susceptible hosts (olives, almond, myrtle –leaf milkwort, periwinkle). Acquisition rates determined by testing individual insects in quantitative PCR assays, ranging from 5.6% in N. campestris to 22.2% in P. italosignus, whereas no acquisition was recorded for L. tunetana. Successful transmissions were detected in the recipient plants exposed to P. italosignus and N. campestris, whereas no trasmissions occurred with L. tunetana. The known vector Philaenus spumarius has been included in all the experiments for validation. The systematic surveys conducted in 2016 and 2017 provided further evidence on the population dynamics and seasonal abundance of the spittlebug populations in the olive groves.

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Metagenomic De Novo Assembly of an Aquatic Representative of the Verrucomicrobial Class Spartobacteria

mBio ◽

10.1128/mbio.00569-12 ◽

2013 ◽

Vol 4 (3) ◽

Cited By ~ 64

Author(s):

Daniel P. R. Herlemann ◽

Daniel Lundin ◽

Matthias Labrenz ◽

Klaus Jürgens ◽

Zongli Zheng ◽

...

Keyword(s):

16S Rrna ◽

Carbon Cycle ◽

Baltic Sea ◽

Glycoside Hydrolases ◽

16S Rrna Genes ◽

Rrna Genes ◽

Sulfated Polysaccharides ◽

The Baltic Sea ◽

The Baltic

ABSTRACTThe verrucomicrobial subdivision 2 classSpartobacteriais one of the most abundant bacterial lineages in soil and has recently also been found to be ubiquitous in aquatic environments. A 16S rRNA gene study from samples spanning the entire salinity range of the Baltic Sea indicated that, in the pelagic brackish water, a phylotype of theSpartobacteriais one of the dominating bacteria during summer. Phylogenetic analyses of related 16S rRNA genes indicate that a purely aquatic lineage within theSpartobacteriaexists. Since no aquatic representative from theSpartobacteriahas been cultured or sequenced, the metabolic capacity and ecological role of this lineage are yet unknown. In this study, we reconstructed the genome and metabolic potential of the abundant Baltic SeaSpartobacteriaphylotype by metagenomics. Binning of genome fragments by nucleotide composition and a self-organizing map recovered the near-complete genome of the organism, the gene content of which suggests an aerobic heterotrophic metabolism. Notably, we found 23 glycoside hydrolases that likely allow the use of a variety of carbohydrates, like cellulose, mannan, xylan, chitin, and starch, as carbon sources. In addition, a complete pathway for sulfate utilization was found, indicating catabolic processing of sulfated polysaccharides, commonly found in aquatic phytoplankton. The high frequency of glycoside hydrolase genes implies an important role of this organism in the aquatic carbon cycle. Spatiotemporal data of the phylotype’s distribution within the Baltic Sea indicate a connection toCyanobacteriathat may be the main source of the polysaccharide substrates.IMPORTANCEThe ecosystem roles of many phylogenetic lineages are not yet well understood. One such lineage is the classSpartobacteriawithin theVerrucomicrobiathat, despite being abundant in soil and aquatic systems, is relatively poorly studied. Here we circumvented the difficulties of growing aquaticVerrucomicrobiaby applying shotgun metagenomic sequencing on a water sample from the Baltic Sea. By using a method based on sequence signatures, we were able toin silicoisolate genome fragments belonging to a phylotype of theSpartobacteria. The genome, which represents the first aquatic representative of this clade, encodes a diversity of glycoside hydrolases that likely allow degradation of various complex carbohydrates. Since the phylotype cooccurs withCyanobacteria, these may be the primary producers of the carbohydrate substrates. The phylotype, which is highly abundant in the Baltic Sea during summer, may thus play an important role in the carbon cycle of this ecosystem.

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A non-targeted metabolomics study on Xylella fastidiosa infected olive plants grown under controlled conditions

Scientific Reports ◽

10.1038/s41598-020-80090-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Asmae Jlilat ◽

Rosa Ragone ◽

Stefania Gualano ◽

Franco Santoro ◽

Vito Gallo ◽

...

Keyword(s):

Xylella Fastidiosa ◽

Bacterial Pathogen ◽

Olive Tree ◽

Susceptible Variety ◽

Leaf Extracts ◽

Metabolomics Study ◽

Olive Quick Decline Syndrome ◽

Olive Trees ◽

Test Plants ◽

Targeted Approach

AbstractIn the last decade, the bacterial pathogen Xylella fastidiosa has devastated olive trees throughout Apulia region (Southern Italy) in the form of the disease called “Olive Quick Decline Syndrome” (OQDS). This study describes changes in the metabolic profile due to the infection by X. fastidiosa subsp. pauca ST53 in artificially inoculated young olive plants of the susceptible variety Cellina di Nardò. The test plants, grown in a thermo-conditioned greenhouse, were also co-inoculated with some xylem-inhabiting fungi known to largely occur in OQDS-affected trees, in order to partially reproduce field conditions in terms of biotic stress. The investigations were performed by combining NMR spectroscopy and MS spectrometry with a non-targeted approach for the analysis of leaf extracts. Statistical analysis revealed that Xylella-infected plants were characterized by higher amounts of malic acid, formic acid, mannitol, and sucrose than in Xylella-non-infected ones, whereas it revealed slightly lower amounts of oleuropein. Attention was paid to mannitol which may play a central role in sustaining the survival of the olive tree against bacterial infection. This study contributes to describe a set of metabolites playing a possible role as markers in the infections by X. fastidiosa in olive.

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