19 research outputs found
Phytosanitary Rules for the Movement of Olive (Olea europaea L.) Propagation Material into the European Union (EU)
No full textPhytosanitary legislation involves government laws that are essential to minimize the risk of the introduction and diffusion of pests, especially invasive non-native species, as a consequence of the international exchange of plant material, thus allowing us to safeguard agricultural production and biodiversity of a territory. These measures ensure compliance with adequate requirements relating to the absence of pests, especially of harmful quarantine organisms through inspections and diagnosis tests of the consignments to ascertain the presence of the pests concerned. They also regulate the eradication and containment measures that are implemented in the eventuality of an unintentional introduction of these organisms. In the present contribution, the current plant protection legislation for the exchange of plants or propagation material within the European Union or for export to foreign countries, represented by Regulation (EU) 2016/2031, has been reviewed, with a particular focus on the olive tree (Olea europaea L.). Furthermore, a brief summary of the main olive tree pests transmissible with the propagation material is also reported, indicating their current categorization with respect to the relative quarantine status
exploits pit membranes of susceptible olive cultivars to spread systemically in the xylem
No full textXylella fastidiosa subspecies pauca strain De Donno (XfDD) ST53 is the causal agent of olive quick decline syndrome, a severe disease first described in Apulia, Italy. Although the two local cultivars Cellina di Nardo and Ogliarola Salentina showed high susceptibility, traits of resistance to the bacterium were found in the cultivar Leccino. Previous studies in field-grown olives suggested that vascular occlusions and anatomophysiological properties of the different cultivars played a role in the olive response to XfDD. The present investigation reports observations at the early stage of the infection on artificially inoculated olives. Electron microscope studies showed that XfDD exploits the pit membranes (PMs) of the susceptible cultivar Cellina di Nardo to spread systemically. In this cultivar, PMs were degraded upon XfDD infection, suggesting activity of bacterial cell wall-degrading enzymes. Moreover, occluded vessels contained an amorphous electrondense matrix resembling gum. Conversely, in Leccino, occluded vessels were mainly filled by callose-like granules that tightly entrapped XfDD cells. In addition, PMs from Leccino had a compact undegraded structure that was not permeable to XfDD. Our study suggests that exploitation of PMs is a key event in the infection process of X. fastidiosa subsp. pauca ST53 in susceptible olive cultivars
EVALUATION OF MINOR APULIAN OLIVE GENOTYPES FOR RESISTANCE TO XYLELLA FASTIDIOSA
No full textThe spread of olive quick decline syndrome (OQDS) caused by the bacterium
Xylella fastidiosa subsp. pauca is threatening Apulia's olive resources,
damaging the regional economy and landscape heritage. To reduce the impact
of the disease, a breeding program has been launched in 2017 aimed at
identifying new sources of resistance to expand the range of varieties that
can be used in the infected areas, together with the resistant varieties
“Leccino” and "FS17". One hundred olive samples, including 19 unknown
accessions from free pollination of Cv. Simone and 81 minor local
cultivars, were grown in the epidemic-affected areas in Apulia and tested
for resistance in a three-block randomized scheme field trial by
artificially infecting them with an X. fastidiosa strain. All cultivars
were genotyped in advance with 10 SSR markers to identify synonyms and
homonyms. Genotypes were evaluated for symptomatology, colony forming units
(cfu)/ml, and Cq value after 4 (2021), 5 (2022), and 6 (2023) years postinoculation
by Real-Time PCR assay. Molecular data were used to investigate
the genetic relationships between the resistant genotypes to provide clues
to start new olive breeding programs. The first results identified some
promising genotypes which show low symptoms, low number of cfu, and high Cq
values which indicate a potential resistance to the disease, comparable to
that of Leccino. The investigation will be continued to consolidate these
results
APULIAN OLIVE GERMPLASM AS POTENTIAL SOURCES OF RESISTANCE TO XYLELLA FASTIDIOSA
No full textThe olive tree (Olea europaea subsp. europaea var. europaea) represents the
cornerstone crop of Apulian economic system based on the production of oil
and table olives. During the last years, the high genetic variability of
Apulia's olive germplasm is being exposed to a risk of genetic erosion due
to social, economic, and climatic changes. In addition, since 2013, the
spread of the gram-negative bacterium Xylella fastidiosa subsp. pauca,
which is responsible for the olive tree rapid decline syndrome (OQDS), has
menaced Apulia's olive biodiversity, damaging the regional economy and
landscape heritage.
To reduce the impact of Xylella fastidiosa, breeding programs have been
started to identify agronomically interesting traits and new sources of
tolerance or resistance.
So far, two cultivars "Leccino" and "FS17" (also known as "Favolosa")
showed resistance to X. fastidiosa in contrast to the susceptible cultivars
"Cellina di Nardò" and "Ogliarola salentina". In addition, recent studies
have shown a moderate tolerance in "Frantoio," "Toscanina," "Termite di
Bitetto," "Maiatica," "Dolce di Cassano," "Oliastro," "Nociara," and
"Nocellara Etnea."
This study aims to investigate the variability of interactions with
X. fastidiosa of a large panel of Apulian olive genotypes.
Sixty olive samples (50 cultivars and 10 unknown genotypes) were grown up
in an experimental field, following a randomized block with 5 replicates,
located in the west part of the infected area in province of Lecce, and
they were inoculated with X. fastidiosa. Monitoring of colony-forming units
(CFU) by RealTime-PCR assay allowed to identify a different behavior of the
genotypes to the infection, based on the Cq values. A preliminary subset of
most promising tolerant genotypes (PT) including both cultivars and
unknown, was identified and characterized by molecular analysis with a set
of 10 SSR markers. The allelic profiles were compared with the molecular
profiles deposited in the Di.S.S.P.A database consisting of about 600 olive
genotypes widespread in the Mediterranean basin. Lynch and Ritland Method
(LRM), Neighbor-joining and STRUCTURE analysis allowed to highlight cases
of synonymy and homonymy, evaluate the genetic relationships between
unknown olive genotypes and cultivars, and investigate the genetic
structure of this Apulian olive germplasm
Isolation and molecular characterization of a Xylella fastidiosa subsp. multiplex strain from almond (Prunus dulcis) in Apulia, Southern Italy
No full textXylella fastidiosa is a xylem-limited phytopathogenic bacterium under regulation in the European Union as a priority pest. Given the potential risk posed by this pathogen to cultivated and ornamental plants, mandatory annual surveys and laboratory testing are required in Member States to early detect outbreaks. In the course of surveys carried out during early spring 2024 in the Apulia region (Southern Italy), X. fastidiosa subsp. multiplex was identified using quantitative real-time Polymerase Chain
Reaction (qPCR), in a non-symptomatic sample from an almond tree (Prunus dulcis) in an orchard located in Santeramo in Colle, in Bari province. Multilocus sequence typing (MLST) was used to identify the subspecies and sequence type (ST) of the bacterium using the genomic DNAs extracted from the infected sample. Comparative sequence analysis of the seven MLST allele genes indicated that the obtained nucleotide
sequences completely matched allele sequences of X. fastidiosa in PubMLST database corresponding to the allelic profile (Sequence Type) ST26 related to subsp. multiplex. Bacterial colonies consistent in morphology with X. fastidiosa were isolated from asymptomatic host samples and identity was confirmed by real-time PCR analysis. This is the first report of detection of X. fastidiosa subsp. multiplex ST26 in the EU
Apulian Autochthonous Olive Germplasm: A Promising Resource to Restore Cultivation in Xylella fastidiosa-Infected Areas
No full textThe olive tree (Olea europaea subsp. europaea var. europaea) represents the cornerstone crop of Apulian agriculture, which is based on the production of oil and table olives. The high genetic variability of the Apulian olive germplasm is at risk of genetic erosion due to social, economic, and climatic changes. Furthermore, since 2013, the spread of the Gram-negative bacterium Xylella fastidiosa subsp. pauca responsible for the olive quick decline syndrome (OQDS) has been threatening olive biodiversity in Apulia, damaging the regional economy and landscape heritage. The aim of this study was to investigate the differential response to X. fastidiosa infection in a collection of 100 autochthonous Apulian olive genotypes, including minor varieties, F1 genotypes, and reference cultivars. They were genotyped using 10 SSR markers and grown for 5 years in an experimental field; then, they were inoculated with the bacterium. Symptom assessments and the quantification of bacterium using a qPCR assay and colony forming units (CFUs) were carried out three and five years after inoculation. The study allowed the identification of nine putatively resistant genotypes that represent a first panel of olive germplasm resources that are useful both for studying the mechanisms of response to the pathogen and as a reserve for replanting in infected areas
COMPARATIVE TRANSCRIPTOME ANALYSIS OF FOUR OLIVE CULTIVARS IN RESPONSE TO INFECTION BY XYLELLA FASTIDIOSA
No full textThe recent outbreak of Olive Quick Decline Syndrome (OQDS) caused by the
bacterium Xylella fastidiosa subsp. pauca is radically changing agriculture
on the Salento peninsula in the Apulia Region, in Southern Italy. Despite
great efforts, it has not yet been possible to bring the disease under
control, so a better knowledge of the mechanisms of disease ethiology is
needed. The main focus of this project was a comparative transcriptome
analysis of four olive cultivars known for their different susceptibilityto
Xylella: Leccino and Donna Francesca as tolerant, and Oliva Rossa and
Cellina as susceptible. Olive samples were grown in certified screenhouseat
DiSSPA- University of Bari Aldo Moro, and for each cultivar, three
replicates from healthy plants and three replicates infected with X.f. were
analysed. The total RNA was extracted from leaf and pidicel tissue using a
commercial kit, the RNA-seq libraries were synthesized and sequenced on
Illumina platform Novaseq 6000. The analysis revealed genes with
differential expression in the two resistant and the two susceptible
varieties. Data analysis revealed a complex pattern of gene expression with
more than 800 differentially expressed genes (DEGs) including a number of
defense-related genes
An integrated strategy for pathogen surveillance unveiled Xylella fastidiosa ST1 outbreak in hidden agricultural compartments in the Apulia region (Southern Italy)
No full textAnnual surveillance programs for the plant pathogenic bacterium Xylella fastidiosa are implemented in Europe as part of the preventive phytosanitary strategies enforced to face the emergence of the detrimental infections reported in olives in southern Italy. The programs include inspections and sampling of host plants by prioritizing those showing suspicious symptoms or those known to be highly susceptible to different strains and subspecies of the bacterium. In the framework of these programs numerous outbreaks have been unraveled, with several strains and subspecies found to infect a relatively large host range in France, Spain, Portugal and Italy. Here we report the results of an integrated surveillance approach implemented in the Apulia Region (southern Italy), where a conventional survey program on host plants is complemented by monitoring and testing for X. fastidiosa the insect vectors. In the framework of this program, bacterium-positive spittlebugs were intercepted in the Xylella-free area of the region, close to one of the most relevant Italian table grape production district. Such findings prompted further investigation to identify the bacterial reservoir in the host plants. Almond and grapevine were found to be the most frequently infected hosts, with infections caused by isolates of X. fastidiosa subspecies fastidiosa ST1. Investigations are ongoing to assess the extent and history of the outbreak, to assess and estimate the potential impacts, and define the best options for its containment
Resistenza a Xylella fastidiosa in diverse cultivar di olivo
No full textOSSERVAZIONI E RILIEVI di campo integrati
da saggi diagnostici effettuati su diverse cultivar in
un’area fortemente infetta da Xylella fastidiosa confermano
i fenomeni di resistenza già osservati in
precedenti studi sulla cultivar Leccino e individuano nella selezione
FS-17® un’ulteriore e potenziale fonte di resistenza al batterio.
Al contrario, si rafforzano le evidenze sull’elevata suscettibilità
delle cultivar Cellina di Nardò e Ogliarola salentin
Re.Ger.O.P.: An Integrated Project for the Recovery of Ancient and Rare Olive Germplasm
No full textThe olive tree is one of the most important economic, cultural, and environmental
resources for Italy, in particular for the Apulian region, where it shows a wide diversity.
The increasing attention to the continuous loss of plant genetic diversity due to social,
economic and climatic changes, has favored a renewed interest in strategies aimed at the
recovery and conservation of these genetic resources. In the frame of a project for the
valorization of the olive Apulian biodiversity (Re.Ger.O.P. project), 177 minor genotypes
were recovered in different territories of the region. They were submitted to morphological,
molecular, technological and phytosanitary status analysis in comparison with reference
cultivars, then they were propagated and transferred in an ex situ field. All the available
information was stored in an internal regional database including photographic
documentation and geographic position. The work allowed obtaining information about
the genetic diversity of Apulian germplasm, to clarify cases of homonymy and synonymy,
to check the sanitary status, and to identify candidate genotypes useful both to set up
breeding programs and to enrich the panel of olive cultivars available to farmers for
commercial exploitation
