Massimiliano Morelli

Massimiliano Morelli
Italian National Research Council | CNR · Institute for Sustainable Plant Protection

Biologist, PhD in Crop Protection

About

133
Publications
27,227
Reads
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1,080
Citations
Citations since 2016
93 Research Items
1047 Citations
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Introduction
Massimiliano Morelli currently works at the Italian National Research Council, Institute for Sustainable Plant Protection, in Bari (Italy). Massimiliano does research in Bacterial and Viral Diseases of plants. He is currently a member of the research team coordinating the H2020-funded projects 'POnTE' (Pest Organisms Threatening Europe) and 'XF-ACTORS' (Xylella Fastidiosa Active Containment Through a multidisciplinary-Oriented Research Strategy).'
Additional affiliations
November 2015 - present
National Research Council (CNR)
Position
  • Fixed-Term Researcher (RTD)
July 2015 - October 2015
Università degli Studi di Bari Aldo Moro
Position
  • Volunteer Trainee
May 2014 - July 2015
Italian National Research Council
Position
  • Independent Contractor
Education
January 2009 - January 2012
Università degli Studi di Bari Aldo Moro
Field of study
  • Crop Protection
October 2005 - October 2006
Università degli Studi di Bari Aldo Moro
Field of study
  • Qualified Technician for Phythopathological Diagnostics
October 2003 - July 2005
Università degli Studi di Bari Aldo Moro
Field of study
  • Environmental and Evolutionary Biology

Publications

Publications (133)
Article
Full-text available
This Scientific report provides an update of the Xylella spp. host plant database, aiming to provide information and scientific support to risk assessors, risk managers and researchers dealing with Xylella spp. Upon a mandate of the European Commission, EFSA created and regularly updated a database of host plant species of Xylella spp. The current...
Article
Full-text available
Following a request from the European Commission, EFSA was asked to create and regularly update a database of host plant species of Xylella spp. The mandate now covers the period 2021–2026 and EFSA is requested to release an update of the database twice per year. The aim of the database is to provide information and scientific support to risk asses...
Article
Full-text available
The root-endophytic fungus Piriformospora indica (=Serendipita indica) has been revealed for its growth-promoting effects and its capacity to induce resistance in a broad spectrum of host plants. However, the bioefficacy of this fungus had not yet been tested against any pathogen affecting onion (Allium cepa). In this study, the biocontrol potency...
Article
Full-text available
Since 2013, Xylella fastidiosa Wells et al. has been reported to infect several hosts and to be present in different areas of Europe. The main damage has been inflicted on the olive orchards of southern Apulia (Italy), where a severe disease associated with X. fastidiosa subspecies pauca strain De Donno has led to the death of millions of trees. Th...
Article
Full-text available
Following a request from the European Commission, EFSA was asked to create and regularly update a database of host plant species of Xylella spp. Complying with an extension of the previous mandate, which now covers the period 2021-2026, the current version of Xylella spp. host plant database updates the previous release dated April 2020. Informativ...
Conference Paper
Full-text available
Prevalence and bacterial population size of Xylella fastidiosa (Xf) were studied in multivarietal olive groves located in the demarcated infected area of Apulia (southern Italy), under high natural pressure of inoculum. Surveys to assess the occurrence of typical Xylella-induced symptoms and the prevalence of infections included the cultivars Oglia...
Conference Paper
Full-text available
The compelling search for a strategy to tackle Xylella fastidiosa strain 'De Donno' and the Olive Quick Decline Syndrome (OQDS) it causes in olive trees, led us to explore the possibility to identify potential biocontrol agents among the microbial communities naturally inhabiting xylem vessels of infected trees. To this aim, we pursued a multiappro...
Conference Paper
Full-text available
Several studies have been conducted on the epidemiology of the virulent pathogen X. fastidiosa subsp. pauca strain 'De Donno' that is causing a severe disease in olive trees, but limited data are available on its phenotypic and biological traits. To fill this knowledge gap, the in vitro behaviour of the strain was investigated, exploring relevant b...
Conference Paper
Full-text available
Xylella fastidiosa (Xf) uses a cell-cell communication system to promote collective behaviors within the population. Such system, named Quorum sensing as it is based on cell density, relies on the production, perception, and response to chemical signals that regulate the expression of genes encoding virulence factors or responsible of the bacterial...
Conference Paper
Full-text available
Remote sensing efforts made as part of European initiatives via POnTE, XF-ACTORS and the JRC, as well as through regional programs, have focused, among others, on the development of algorithms for the early detection of Xylella fastidiosa (Xf)-induced symptoms. Airborne campaigns carried out between 2016 and 2019 collected high-resolution hyperspec...
Article
Full-text available
Xylella fastidiosa subsp. pauca strain De Donno has been recently identified as the causal agent of a severe disease affecting olive trees in a wide area of the Apulia Region (Italy). While insights on the genetics and epidemiology of this virulent strain have been gained, its phenotypic and biological traits remained to be explored. We investigate...
Book
Full-text available
The term “endophytes” usually refers to communities of microorganisms, typically bacteria or fungi, which colonize the internal portion of plants, mainly vascular tissues, interacting with the host in either beneficial or neutral mode. The scientific community customarily classifies endophytes into three main subsets based on facultative, obligate...
Article
Full-text available
The dynamics of Xylella fastidiosa infections in the context of the endophytic microbiome was studied in field-grown plants of the susceptible and resistant olive cultivars Kalamata and FS17. Whole metagenome shotgun sequencing (WMSS) coupled with 16S/ITS rRNA gene sequencing was carried out on the same trees at two different stages of the infectio...
Article
Full-text available
With the increasing social concern in avoiding, or at least reducing, the application of pesticides and chemical fertilizers, in favor of sustainable eco-friendly alternatives, the search for beneficial microorganisms and microbial-derived compounds has become one of the most popular Research Topics in the field of plant-microbe interactions (Cardo...
Article
Full-text available
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 sa...
Conference Paper
Full-text available
Numerous attempts have been made to test the use of endophytic bacteria to control diseases caused by Xylella fastidiosa (Xf), but promising results obtained in vitro have often proved inadequate once transferred to the field. A new encouraging possibility came from the observation that the bacterium Paraburkholderia phytofirmans PsJN, widely studi...
Conference Paper
Full-text available
Xylella fastidiosa subsp. pauca strain De Donno has been recently identified as the causal agent of a severe disease affecting olive trees in a wide area of the Apulia Region (Italy). While insights on the genetics and epidemiology of this virulent strain have been gained, the complex network of interactions with the main susceptible host remains t...
Conference Paper
Full-text available
Xylella fastidiosa (Xf) is continuing to emerge as a devastating bacterial pathogen for many economically relevant species. Xf subsp. pauca strain De Donno is associated with olive quick decline syndrome (OQDS), a destructive disease occurring in the southern area of Apulia (Italy). In susceptible olive cultivars, symptoms are characterised by init...
Conference Paper
Full-text available
Olive quick decline syndrome (OQDS) is a devastating olive disease, which emerged few years ago in the region of Apulia (southern Italy) as a result of the bacterial infections caused by Xylella fastidiosa subsp. pauca. Bacterial infections were consistently associated with severe desiccations on the local cvs Cellina di Nardò and Ogliarola salenti...
Conference Paper
Full-text available
As olive is the most widespread fruit tree in Montenegro, eventual detection of the bacterium Xylella fastidiosa would cause great economic losses, besides implying the implementation of a permanent monitoring campaign. This is especially due to the importance of early detection of the bacteria as well as its vector(s) for the timely implementation...
Article
Full-text available
Olive Quick Decline Disease (OQDS) is a devastating olive disease emerged few years ago in the region of Apulia (southern Italy) as a result of the bacterial infections caused by Xylella fastidiosa subsp. pauca. Bacterial infections were consistently associated to severe desiccations on the local cvs Cellina diNardò and Ogliarola salentina,whereas...
Conference Paper
Full-text available
Diffusible lipid species are exploited by bacteria for regulating cell motility, cell-to-cell communication, activation of metabolism and proliferation. The most widely investigated lipid family is represented by diffusible signal factors (DSFs) responsible for quorum sensing. Xylella fastidiosa (Xf) uses the DSFs to coordinate genes involved in th...
Conference Paper
Full-text available
La determinazione del profilo ionico di foglie sintomatiche e asintomatiche è stata effettuata su due cultivar di olivo che rispondono in maniera diversa all’infezione di Xylella fastidiosa. Lo studio ha lo scopo di esplorare i meccanismi coinvolti nello sviluppo dei sintomi e/o nell’interazione pianta patogeno.
Conference Paper
Full-text available
Recenti investigazioni hanno mostrato l’efficacia del batterio Paraburkholderia phytofirmans PsJN nel ridurre gli effetti di Pierce’s Disease in vite. Il nostro studio intende verificare le possibilità di impiego di PsJN come agente di controllo biologico di X. fastidiosa, valutando le sue modalità di colonizzazione e persistenza in olivo e misuran...
Conference Paper
Full-text available
Xylella fastidiosa usa acidi grassi cis-2-insaturi come specie lipidiche diffusibili. Queste molecole diffondono nell’ospite per comunicare con altre cellule e modulare risposte geniche relative a produzione di biofilm e motilità. In questo lavoro presentiamo l’identificazione di DSFs estratti da terreni di coltura in cui X. fastidiosa è stato prop...
Conference Paper
Full-text available
Numerous research efforts are currently underway to identify novel biocontrol agentsfor the management of diseases associated with Xylella fastidiosa. Despite the encouraging premises, most of these studies proved unable to provide long-term effects or failed once they were examined at the field-scale. An intriguing exception was that of the rhizos...
Conference Paper
Full-text available
The plant vascular system is the route of transport of mineral elements that play key roles in controlling a multitude of metabolic functions. The xylem colonizer Xylella fastidiosa, like any other endophyte, has enacted a series of strategies to compete with the host for mineral ions, and ensure its growth. Many of the strategies are linked to the...
Conference Paper
Full-text available
The core microbiome has been increasingly recognized to be central to plant health. However, the extent to which host plant may play a role in shaping its core microbiome and their implications for host susceptibility/resistance to a particular disease, remains poorly understood. Such knowledge, besides providing insight on the potential role of co...
Conference Paper
Full-text available
Different chemical species are utilized from bacteria as signals for cell-to-cell communication during Quorum Sensing. A widely investigated family of chemical signals from plant pathogenic bacteria are the diffusible signal factors (DSFs). In Xylella fastidiosa and related Xanthomonas species, these DSFs are produced by a synthase (RpfF) and inter...
Conference Paper
Full-text available
Field observations carried out in Salento (Italy) in the area infected by Xylella fastidiosa (Xf) evidenced that olive trees of the cultivar 'Leccino' show milder symptoms, if compared to those observed in the susceptible cv. 'Ogliarola salentina'. A transcriptome profiling of the two cultivars infected with the Xf De Donno strain revealed differen...
Conference Paper
Full-text available
Microbial endophytes are well known to protect host plants against pathogens, thus representing a promising strategy for the control of Xylella fastidiosa in olive trees. Although their high potential for being used as biocontrol agents, there are pending questions regarding to which extent endophytes enhance plant defences. For example, how microb...
Article
Full-text available
Europe’s major X. fastidiosa outbreaks have progressed steadily in the past years as data on the bacterial strains causing them, and on the host range and vectors of the pathogen in various regions, became available. The initial uncertainty around these critical epidemiological aspects of the X. fastidiosa invasions hampered estimates of their rate...
Conference Paper
Full-text available
Biofilm formation is among the relevant virulence mechanisms of several plant pathogenic bacteria, including Xylella fastidiosa. Mainly composed of exopolysaccharides, biofilm allows bacterial cells to adhere to the surfaces and form communities protected from the hostile xylematic environment. Previous studies have shown that X. fastidiosa biofilm...
Conference Paper
Full-text available
Xylella fastidiosa (Xf) is a xylem-limited bacterial plant pathogen that is responsible for Olive Quick Decline Syndrome (OQDS), a devastating disease reported in Salento (Apulia, Italy). Field observations show that olive cv. ‘Leccino’ show milder symptoms when compared to the highly susceptible cv. ‘Ogliarola’. A prior transcriptome analysis of ‘...
Article
Full-text available
Plant pathogens cause significant losses to agricultural yields and increasingly threaten food security 1 , ecosystem integrity and societies in general2-5. Xylella fastidiosa is one of the most dangerous plant bacteria worldwide, causing several diseases with profound impacts on agriculture and the environment 6 . Primarily occurring in the Americ...
Conference Paper
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Early detection of infections in programs of production of virus-tested vine propagating material is of paramount importance to reduce costs of maintaining sanitized plants. In Apulia (Italy), the Regional Project “Re.Ge.Vi.P.”, aiming to the recovery, conservation and sanitary improvement of autochthonous vine cultivars, gave the cue to assess the...
Article
The detection of the four grapevine viruses (GLRaV-1, GLRaV-3, GFLV and ArMV) regulated in European Union plant material certification, requires sensitive and specific diagnostic tools. A strategy of simultaneous detection in a real-time single tube amplification was developed, based on the EvaGreen binding dye. The melting curve analysis (MCA) of...
Article
Full-text available
In autumn 2013, the presence of Xylella fastidiosa, a xylem-limited Gram-negative bacterium, was detected in olive stands of an area of the Ionian coast of the Salento peninsula (Apulia, southern Italy), that were severely affected by a disease denoted olive quick decline syndrome (OQDS). Studies were carried out for determining the involvement of...
Conference Paper
Full-text available
Xylella fastidiosa (Xf) subsp. pauca phylotype ST53 is responsible for a devastating disease on olive crops, in the southern area of Apulia (Italy). Despite the vast literature available on Xf-host relationships, scarce and barely recent efforts have been made to investigate the potential role of microbial interactions on the disease phenotype of X...
Conference Paper
Full-text available
A large program of mechanical inoculations and vector-mediated transmission experiments was launched in the past 2 years, and continuously implemented, in the attempt to disclose the role of the olive-infecting strain of X. fastidiosa in the olive quick decline disease (OQDS) and to ascertain the crop species under threat due to the expansion of th...
Conference Paper
Full-text available
So far no effective field applicable therapeutic strategy exists to combat the severe diseases associated to X. fastidiosa. Therefore, various experimental applications to seek for a sustainable approach for the mitigation of the impact of the infections on olive trees were explored. In 2015-2016, four field trials were set in the infected area in...
Conference Paper
Full-text available
A multi-factorial strategy is required to co-exist with X. fastidiosa infections, which are devastating olive trees in the southern area of Apulia (Italy). Observations in the outbreak area can provide information on potential approaches for containment. Olive cvs Leccino and FS17 show lessened symptoms and host lower bacterial populations (1,2) th...
Conference Paper
Full-text available
X. fastidiosa subsp. pauca causes diseases in citrus and olive plants. Fortunately, there are citrus species and olive varieties more tolerant to X. fastidiosa and therefore good genotypes to search for genetic sources of resistance. Following this approach, global gene expression analyses were recently achieved using Citrus reticulata cv. Ponkan a...
Conference Paper
Full-text available
X. fastidiosa is a plant pathogenic bacterium, which is causing the ‘Olive Quick Decline Syndrome’ (OQDS), on olive trees in the southern part of Apulia region. The knowledge of mechanisms regulating olive- X. fastidiosa interactions is fundamental to develop biocontrol strategies. In Pierce’s Disease (PD) the pathogen virulence relies on a fine ba...
Conference Paper
Full-text available
Endophytic bacteria are of biotechnological and agronomic interest as they promote plant healthiness by producing and secreting plant growth regulators, and antagonizing phytopathogens through the induction of resistance mechanisms, and the supply of nutritional elements. One of the factors that may influence the behavior of olive towards the ‘quic...
Conference Paper
Full-text available
While different sources of natural resistance to X. fastidiosa have been described in grapevines and citrus, lack of solid information exists on possible sources of resistance/tolerance in the cultivars that characterize the wide olive germplasm. Preliminary field observations and laboratory analyses of a few cultivars, have shown that differential...
Article
Full-text available
In Italy, grapevine certification system requires the status of “virus controlled” for multiplication and commercialization. This system entails free plant propagation material from Grapevine virus A (GVA), Grapevine virus B (GVB), Grapevine leafroll-associated virus 1, 2, 3 (GLRaV-1, -2, -3), Grapevine fanleaf virus (GFLV), Grapevine fleck virus (...
Conference Paper
Full-text available
A study of the sanitary status of ancient native grapevine cultivars and biotypes of Apulia (Italy) was performed in the framework of the project Re.Ge.Vi.P. (“Recovery of Apulian grape germplasm”), A total of 80 native table and wine grapes (the majority of which described in historical pre-philloxera reports) were recovered throughout the Apulian...
Conference Paper
Full-text available
In Italy, grapevine certification system requires the status of “virus controlled” for multiplication and commercialization. This system entails free plant propagation material from Grapevine virus A (GVA), Grapevine virus B (GVB), Grapevine leafroll-associated virus 1, 2, 3 (GLRaV-1, -2, -3), Grapevine fanleaf virus (GFLV), Grapevine fleck virus (...
Article
Full-text available
The quarantine bacterium Xylella fastidiosa is responsible for several diseases in a wide range of cultivated and wild plants. Few efforts have been made to investigate the potential use of endophytic symbionts on the disease phenotype of Xf-infected plants. The aim of our study is to evaluate if Paraburkholderia phytofirmans PsJN strain, a plant g...
Article
Full-text available
Xylella fastidiosa (Xf) is a xylem-limited bacterium, regulated as a quarantine pest, that is causing a devastating disease on olive crops in the southern area of Apulia (Italy) and whose potential spread in the Mediterranean area poses a severe threat to EU agriculture and landscape environment. Xf virulence is related to the expression of a clust...
Chapter
Full-text available
A devastating outbreak of a strain of Xylella fastidiosa is ravaging the olive trees of southern Puglia, Italy (Saponari et al., 2015). The bacterium, discovered in 2013, causes the Olive Quick Decline Syndrome (OQDS), a destructive disease characterized by apical and marginal leaf scorching, extensive branch and twig dieback, followed by death of...
Conference Paper
Full-text available
A strain of Xylella fastidiosa is ravaging the olive trees of Southern Apulia, Italy (Saponari et al., 2013). The bacterium causes the Olive Quick Decline Syndrome (OQDS), a disease showing symptoms of apical and marginal leaf scorching, extensive branch and twig dieback and death of the trees (Martelli et al., 2016). Transmission tests demonstrate...
Article
Full-text available
Gli istituti di ricerca pugliesi riportano i risultati ottenuti dall’impiego di attivatori delle difese della pianta e dell’N-acetilcisteina per il contenimento dei sintomi del complesso del disseccamento rapido dell’olivo. Recent experimentation to control Xylella fastidiosa The Apulian Research Institutes report the results obtained using plant...
Conference Paper
Full-text available
Xylella fastidiosa (Xf) is a xylem-limited bacterium, regulated as a quarantine pest, that is causing a devastating disease on olive crops, in the southern area of Apulia (Italy). Its potential spread in the Mediterranean area poses a severe threat to EU agriculture and landscape environment. Despite the vast literature on Xf relationships with hos...
Conference Paper
Full-text available
The meadow spittlebug Philaenus spumarius (L.) has been identified as vector of Xylella fastidiosa subsp. pauca strain CoDiRO infecting several host plants in Apulia (Southern Italy), and causing a major bacterial disease on olive trees. Evidences of differential olive cultivar susceptibility to the bacterial infections were obtained from phenotypi...
Article
Full-text available
Osservazioni e rilievi di campo integrati da un programma di campionamenti e saggi diagnostici di laboratorio confermano in alcune delle varietà oggetto di studio una minore incidenza delle infezioni di Xylella fastidiosa, a cui sono associate sintomatologie di deperimento e manifestazioni di disseccamento più lievi e attenuate rispetto a quanto os...
Conference Paper
Full-text available
La Xylella fastidiosa è un batterio fitopatogeno gram-negativo, che vive e si riproduce nei vasi xylematici delle piante ospiti, impedendo, all’interno di tali apparati conduttori, il trasporto di acqua e soluti verso le foglie. Nota sin dalla fine del secolo scorso nelle Americhe, a causa dei gravi danni prodotti su colture di interesse agrario, p...
Article
Full-text available
A quince tree showing severe symptoms of a previously undescribed viral disease occurring in northern Apulia (Italy) was analysed using high-throughput sequencing of small RNA libraries, leading to the identification of a new strain of apple green crinkle associated virus (isolate AGCaV-CYD) showing peculiar traits. RT-PCR with specific primers det...
Article
Full-text available
The recent findings of the plant pathogenic bacterium Xylella fastidiosa (Xf), infecting several plant species in Italy and France, raised major concerns for its potential impact on the EU and Mediterranean agriculture. In the current EU outbreaks, olive is the predominantly affected crop, in which the bacterium has been consistently associated wit...
Conference Paper
Full-text available
Recent studies demonstrated that the virulence of Xylella fastidiosa relies on a fine balance between more motile bacterial forms, able to move and proliferate within xylem vessels, and sticky cells forming a biofilm, which are responsible for vessels blockage and insect acquisition. This different behavior is regulated in a cell density-dependent...
Conference Paper
Full-text available
The CoDiRO strain of Xylella fastidiosa (Xf), which is devastating olive trees in the Apulia Region (southern Italy), represents the first documented establishment of this plant pathogenic bacterium in Europe. Diseases induced by Xf have no chemical cure and its pathogenic mechanism(s) are not completely understood. Nevertheless, profiles and relat...
Conference Paper
Full-text available
While different sources of natural resistance to Xylella fastidiosa (Xf) have been described in grapevines and citrus, lack of consolidated information exists on the wide panel of cultivars characterizing the vast olive germplasm. Preliminary observations and analysis on few cultivars, support the evidence that differential responses to Xf infectio...
Conference Paper
Full-text available
The isolation in pure culture of the Xylella fastidiosa is one of the critical steps for establishing comprehensive research programs aiming at investigating its host range, genomics and population genetics. An isolation campaign was started in Apulia in spring 2016 to collect isolates representing several foci in the infected demarcated area of Ap...
Conference Paper
Full-text available
The International Research Consortium POnTE (Pest Organisms Threatening Europe) is being funded by the European Commission under the Horizon 2020 programme to investigate four pathogens (i.e. Xylella fastidiosa, Candidatus Liberibacter solanacearum, Hymenoscyphus fraxineus and Phythophthora spp.) representing a major threat to strategic crops and n...
Conference Paper
Full-text available
Endophytes are usually defined as microorganisms that exist and colonize tissues without causing any visible symptoms to the host plant, and can be isolated from surface-sterilized plant tissue or extracted from within the plant. Although the inadequate elimination of nucleic acids after disinfection of plant surfaces, makes the traditional definit...
Conference Paper
Full-text available
Olive Quick Decline Syndrome (OQDS) is a destructive disease of olive (Olea europaea) described in Apulia (Italy), to which the CoDiRO strain of Xylella fastidiosa subsp. pauca (Xfp) is associated. Differently from the severely affected cv. Ogliarola salentina, Xfp-infected plants of the cv. Leccino develop reduced symptoms, which are compatible wi...
Article
Full-text available
Following the introduction and establishment of the plant pathogenic bacterium Xylella fastidiosa (Xf) in the Apulia Region (southern Italy), olive turned to be the main host of the Salentinian bacterial strain and the majorly devastated crop. The mechanism of pathogenicity of Xf is still not completely understood and no means to cure the bacterium...
Article
Full-text available
While different sources of natural resistance to Xylella fastidiosa (Xf) have been described in grapevines and citrus, lack of consolidated information exists on the wide panel of cultivars characterizing the vast olive germplasm. Preliminary observations on few cultivars, support the evidence that differential cultivar responses to Xf infections m...
Article
Full-text available
The CoDiRO strain of Xylella fastidiosa subsp. pauca (Xfp) is ravaging olive (Olea europaea) groves in southern Italy, causing a destructive disease denoted Olive Quick Decline Syndrome (OQDS). Field observations show that the Xfp-infected plants of the cv. Ogliarola salentina develop more severe symptoms than that of cv. Leccino. A global transcri...