Joana Costa

• PhD in Biology (Microbiology)
• Researcher at University of Coimbra

Xanthomonads, including Xanthomonas and Xylella species, constitute a large and significant group of economically and ecologically important plant pathogens. Up-to-date knowledge of these pathogens and their hosts is essential for the development of suitable control measures. Traditional review articles or book chapters have inherent limitations, i...

Sunflower is a short-season crop of the Asteraceae family and the Helianthus genus and is the fourth most important oilseed crop in the world. During a field campaign, unusual symptoms (necrosis and longitudinal cracking of the petiole) were observed in a sunflower crop grown in the region of Kavarna (Dobrich district, Bulgaria) and strains of the...

Xanthomonads, including Xanthomonas and Xylella species, constitute a large and significant group of economically and ecologically important plant pathogens. Up-to-date knowledge of these pathogens and their hosts is essential for the development of suitable control measures. Traditional review articles or book chapters have inherent limitations, i...

In Portugal, the Cova da Beira region is well-known for the production of Prunus spp. and is considered the main peach production area in the country. In the spring of 2021 and 2022, field surveys in peach and nectarine orchards showed symptoms of decline such as cankers, gummosis, dry branches, abortion of flowers, mummified fruits and the partial...

Present, emerging or re-emerging plant diseases due to infection by bacteria of the Lysobacteraceae (syn: Xanthomonadaceae) family are continually challenging food security and cause significant losses to the economies of European countries each year [...]

This Standard describes a diagnostic protocol for Erwinia amylovora

Xylella fastidiosa represents a major threat to important crops worldwide including almond, citrus, grapevine, and olives. Nowadays, there are no efficient control measures for X. fastidiosa, and the use of preventive measures and host resistance represent the most practical disease management strategies. Research on vessel-associated microorganism...

Arbutus unedo L. (strawberry tree) is a multipurpose Ericaceae tree with a circum-Mediterranean distribution and tolerant to abiotic and biotic stresses. The bioactive compounds and edible berries make this species attractive from an economical perspective, which causes a high demand for true to type plants. As micropropagation techniques are quite...

Bacteria in the genus Xanthomonas infect a wide range of crops and wild plants, with most species responsible for plant diseases that have a global economic and environmental impact on the seed, plant, and food trade. Infections by Xanthomonas spp. cause a wide variety of non-specific symptoms, making their identification difficult. The coexistence...

The Pseudomonas syringae pv. actinidiae pandemic has been compromising the production of the kiwifruit industry in major producing countries. Abiotic factors and plant gender are known to influence the disease outcome. To better understand their impact, we have determined the diversity of the leaf bacterial communities using the V5-V6 region of the...

Arbutus unedo L. is a resilient tree with a circum-Mediterranean distribution. Besides its ecological relevance, it is vital for local economies as a fruit tree. Several microorganisms are responsible for strawberry tree diseases, leading to production constrictions. Thus, the development of alternative plant protection strategies is necessary, suc...

Arbutus unedo L. is a resilient tree with a circum-Mediterranean distribution. Besides its ecological relevance, it is vital for local economies as a fruit tree. Several microorganisms are responsible for strawberry tree diseases leading to production constrictions. Thus, the development of alternative plant protection strategies is necessary and b...

Specific scope This Standard describes a diagnostic protocol for Pseudomonas syringae pv. actinidiae. It should be used in conjunction with PM 7/76 Use of EPPO Diagnostic Protocols.¹ Specific approval and amendment Approved in 2014–09. Revised in 2021–06. Authors and contributors are given in the Acknowledgements section.

Background: Xanthomonas citri pv. fuscans (Xcf) and Xanthomonas phaseoli pv. phaseoli (Xpp) are the causal agents of common bacterial blight of bean (CBB), an important disease worldwide that remains difficult to control. These pathogens belong to distinct species within the Xanthomonas genus and have undergone a dynamic evolutionary history inclu...

Bacteria in the genus Xanthomonas infect a wide range of crops and wild plants, with most species responsible for plant diseases that have a global economic and environmental impact on the seed, plant, and food trade. Infections by Xanthomonas spp. cause a wide variety of non-specific symptoms, making their identification difficult. The coexistence...

Maize is one of the most important crops worldwide and is the number one arable crop in Portugal. A transition from the conventional farming system to organic agriculture requires optimization of cultivars and management, the interaction of plant–soil rhizosphere microbiota being pivotal. The objectives of this study were to unravel the effect of p...

Os riscos de natureza biológica apresentam grande diversidade e complexidade, resultado tanto da natureza dos organismos envolvidos como da multiplicidade de processos que podem estar subjacentes à manifestação do próprio risco, o que dificulta a implementação de ações de controlo ou prevenção. De uma forma geral, os riscos biológicos decorrem de i...

Pseudomonassyringae pv. actinidiae (Psa) is a gram-negative bacterium responsible for the bacterial canker in Actinidia chinensis var. deliciosa and A. chinensis var. chinensis, a quarantine organism threatening the kiwifruit industry sustainability. The present study aimed to determine the genetic structure of the endophytic and epiphytic populati...

Pseudomonas syringae pv. actinidiae (Psa) is a quarantine bacterium affecting all the Portuguese main areas of kiwifruit production. We report the draft genome of six Psa strains isolated from symptomatic leaves of Actinidia chinensis cv. deliciosa in a study that determined the genetic population structure of the endophytic and epiphytic populatio...

Strawberry tree (Arbutus unedo L.) is an evergreen Mediterranean tree from cosmopolitan Ericaceae family, well adapted to biotic and abiotic stress. It can grow on poor marginal lands and thrives in the Mediterranean forests due to its sprouting ability after forest fires. It's a source of bioactive compounds with antioxidant activity and its round...

Passion fruit, Passiflora edulis Sims f. edulis, is native to Central and South America and is commercialized in most of the tropical and subtropical zones of the world. Many of the producing countries see their expansion limited owing to the presence of various plant pathogens that challenge the development of this crop (Teixeira et al. 2016). Fus...

Pollination is an important biodiversity-dependent service supporting food provisioning and affecting directly the yield and quality of over 75% of crops worldwide. Actinidia deliciosa is a dioecious species and therefore efficient pollination, i.e., pollen transfer between male and female plants, is a key feature in fruit production. Moreover, kiw...

Soils are discontinuous and heterogeneous ecosystems, with properties determined by environmental factors (i.e. climate, parent material, organisms and time factor). Different soils reflect the impact of the various factors involved in their genesis and, as their physicochemical characteristics shift in different axes (surface and subsurface horizo...

Legionella pneumophila is a ubiquitous bacterium in freshwater environments and in many man-made water systems capable of inducing pneumonia in humans. Despite its ubiquitous character most studies on L. pneumophila virulence focused on clinical strains and isolates from man-made environments, so little is known about the nature and extent of virul...

Background Given the role of spA as a pivotal virulence factor decisive for Staphylococcus aureus ability to escape from innate and adaptive immune responses, one can consider it as an object subject to adaptive evolution and that variations in spA may uncover pathogenicity variations. Results The population genetic structure was deduced from the...

SidJ is a Dot/Icm effector involved in the trafficking or retention of ER-derived vesicles to Legionella pneumophila vacuoles whose mutation causes an observable growth defect, both in macrophage and amoeba hosts. Given the crucial role of this effector in L. pneumophila virulence we investigated the mechanisms shaping its molecular evolution. The...

Some strategies have been found in prokaryotes to adapt to extreme environments, where physicochemical values are higher or lower than that which is considered standard for most living organisms. Saline environments represent a challenge to the survival of microorganisms due to the low water activity and the high concentrations of inorganic ions th...

The biosynthetic pathway for the rare compatible solute mannosylglucosylglycerate (MGG) accumulated by Rhodopirellula baltica, a marine member of the phylum Planctomycetes, has been elucidated. Like one of the pathways used in the thermophilic bacterium Petrotoga mobilis, it has genes coding for glucosyl-3-phosphoglycerate synthase (GpgS) and manno...

Supplementary information

The intracellular accumulation of small organic solutes was described in the marine bacterium Rhodopirellula baltica, which belongs to the globally distributed phylum Planctomycetes whose members exhibit an intriguing lifestyle and cell morphology. Sucrose, α-glutamate, trehalose and mannosylglucosylglycerate (MGG) are the main solutes involved in...

R. baltica extract proton spectrum. Proton spectrum (A) and sugar anomeric region of the proton spectrum (B) acquired at 800.33 MHz of an extract of R. baltica grown at 25°C with 150% ASW in N+ medium. (PDF)

Given the role of type II protein secretion system (T2S) in the ecology and pathogenesis of Legionella pneumophila, it is possible that this system is a target for adaptive evolution. The population genetic structure of L.pneumophila was inferred from the partial sequences of rpoB and from the complete sequence of three T2S structural components (l...

Rubrobacter xylanophilus is the only actinobacterium known to accumulate the organic solute mannosylglycerate (MG); moreover, the accumulation of MG is constitutive. The key enzyme for MG synthesis, catalysing the conversion of GDP-mannose (GDP-Man) and D-3-phosphoglycerate (3-PGA) into the phosphorylated intermediate mannosyl-3-phosphoglycerate an...

Given the role of DotA protein in establishing successful infections and the diversity of host cells interacting with Legionella pneumophila in nature, it is possible that this gene product is a target for adaptive evolution. We investigated the influence of L. pneumophila isolates from natural environments with the molecular evolution of this cruc...

The compatible solute mannosylglucosylglycerate (MGG), recently identified in Petrotoga miotherma, also accumulates in Petrotoga mobilis in response to hyperosmotic conditions and supraoptimal growth temperatures. Two functionally connected genes encoding a glucosyl-3-phosphoglycerate synthase (GpgS) and an unknown glycosyltransferase (gene Pmob_11...

Traditional geothermally heated therapeutic spas, widely distributed in Europe, use water that is not disinfected. The colonization of therapeutic spas by Legionella spp. has been reported and several outbreaks and sporadic cases of legionellosis have been associated with the use of these facilities. We tested the effectiveness of hyperchlorination...

The pathway for the synthesis of glucosylglycerate (GG) in the thermophilic bacterium Persephonella marina is proposed based on the activities of recombinant glucosyl-3-phosphoglycerate (GPG) synthase (GpgS) and glucosyl-3-phosphoglycerate phosphatase (GpgP). The sequences of gpgS and gpgP from the cold-adapted bacterium Methanococcoides burtonii w...

The pathway for the synthesis of the organic solute glucosylglycerate (GG) is proposed based on the activities of the recombinant glucosyl-3-phosphoglycerate synthase (GpgS) and glucosyl-3-phosphoglycerate phosphatase (GpgP) from Methanococcoides burtonii. A mannosyl-3-phosphoglycerate phosphatase gene homologue (mpgP) was found in the genome of M....

Groundwater samples (111) from six different boreholes located in two geographical areas were examined for the presence of legionellae over a 7-year period. The number of Legionella isolates detected was generally low. The colonization of the aquifers was not uniform, and the persistence of Legionella was independent of the hydraulic pumps and the...

Mannosylglycerate (MG) is a common compatible solute found in thermophilic and hyperthermophilic prokaryotes. In this study we characterized a mesophilic and bifunctional mannosylglycerate synthase (MGSD) encoded in the genome of the bacterium Dehalococcoides ethenogenes. mgsD encodes two domains with extensive homology to mannosyl-3-phosphoglycera...

Several isolates, belonging to two new species of the same novel genus of gamma-proteobacteria, were recovered from drilled well (borehole) and spa water at São Gemil in central Portugal. These organisms are phylogenetically most closely related to the strictly intracellular uncultured species of the genus Rickettsiella, which cause disease in arth...