Seasonal Concentration of the Pierce's Disease Bacterium in Grapevine Stems, Petioles, and Leaf Veins

Hopkins, D. L.

doi:10.1094/phyto-71-415

Cited by 90 publications

(75 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Vessels can become occluded by dense colonization, and high frequencies of blocked vessels are associated with disease symptom development (1)(2)(3). X. fastidiosa is responsible for diseases that cause economic loss in many agricultural plants; however, it can also live in symptomless hosts that serve as a source of inoculum (4).…”

mentioning

confidence: 99%

Cell-cell signaling controlsXylella fastidiosainteractions with both insects and plants

Newman

Almeida

Purcell

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

262

296

View full text Add to dashboard Cite

Xylella fastidiosa, which causes Pierce's disease of grapevine and other important plant diseases, is a xylem-limited bacterium that depends on insect vectors for transmission. Although many studies have addressed disease symptom development and transmission of the pathogen by vectors, little is known about the bacterial mechanisms driving these processes. Recently available X. fastidiosa genomic sequences and molecular tools have provided new routes for investigation. Here, we show that a diffusible signal molecule is required for biofilm formation in the vector and for vector transmission to plants. We constructed strains of X. fastidiosa mutated in the rpfF gene and determined that they are unable to produce the signal activity. In addition, rpfF mutants are more virulent than the wild type when mechanically inoculated into plants. This signal therefore directs interaction of X. fastidiosa with both its insect vector and plant host. Interestingly, rpfF mutants can still form in planta biofilms, which differ architecturally from biofilms in insects, suggesting that biofilm architecture, rather than a passive response to the environment, is actively determined by X. fastidiosa gene expression. This article reports a cell-cell signaling requirement for vector transmission. Identification of the genes regulated by rpfF should elucidate bacterial factors involved in transmission and biofilm formation in the insect.

show abstract

mentioning

confidence: 99%

Cell-cell signaling controlsXylella fastidiosainteractions with both insects and plants

Newman

Almeida

Purcell

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

262

296

View full text Add to dashboard Cite

show abstract

“…Understanding the pattern of X. fastidiosa colonization of the xylem and relating this pattern to symptom expression will further our progress in understanding PD as well as the endophytic life-style of the pathogen. To this end, several other studies have analyzed X. fastidiosa in planta using various types of microscopy, including light microscopy (13,19), scanning electron microscopy (35), transmission electron microscopy (24), and immunofluorescence microscopy (4). In these studies, it was determined that the frequency of vessels colonized and blocked by X. fastidiosa in grapes is positively correlated with disease symptom development over the growing season (19) and within individual plants (35).…”

mentioning

confidence: 99%

“…To this end, several other studies have analyzed X. fastidiosa in planta using various types of microscopy, including light microscopy (13,19), scanning electron microscopy (35), transmission electron microscopy (24), and immunofluorescence microscopy (4). In these studies, it was determined that the frequency of vessels colonized and blocked by X. fastidiosa in grapes is positively correlated with disease symptom development over the growing season (19) and within individual plants (35). X. fastidiosa colonies in the xylem were reported to be of different sizes (35), to be either distributed evenly throughout the vessel or appressed against the vessel wall (24), and sometimes to be accompanied by a matrix presumed to be a gel of either plant or bacterial origin; however, no quantitative analysis of these observations has been reported (4,13,24,35).…”

mentioning

confidence: 99%

Use of a Green Fluorescent Strain for Analysis ofXylella fastidiosaColonization ofVitis vinifera

Newman

Almeida

Purcell

et al. 2003

Appl Environ Microbiol

227

207

View full text Add to dashboard Cite

Xylella fastidiosa causes Pierce's disease of grapevine as well as several other major agricultural diseases but is a benign endophyte in most host plants. X. fastidiosa colonizes the xylem vessels of host plants and is transmitted by xylem sap-feeding insect vectors. To understand better the pattern of host colonization and its relationship to disease, we engineered X. fastidiosa to express a green fluorescent protein (Gfp) constitutively and performed confocal laser-scanning microscopic analysis of colonization in a susceptible host, Vitis vinifera. In symptomatic leaves, the fraction of vessels colonized by X. fastidiosa was fivefold higher than in nearby asymptomatic leaves. The fraction of vessels completely blocked by X. fastidiosa colonies increased 40-fold in symptomatic leaves and was the feature of colonization most dramatically linked to symptoms. Therefore, the extent of vessel blockage by bacterial colonization is highly likely to be a crucial variable in symptom expression. Intriguingly, a high proportion (>80%) of colonized vessels were not blocked in infected leaves and instead had small colonies or solitary cells, suggesting that vessel blockage is not a colonization strategy employed by the pathogen but, rather, a by-product of endophytic colonization. We present evidence for X. fastidiosa movement through bordered pits to neighboring vessels and propose that vessel-to-vessel movement is a key colonization strategy whose failure results in vessel plugging and disease.

show abstract

“…However, sampling should be performed during the period of active growth of the plants, usually from late spring to autumn in Europe [57]. For the CoDiRO strain, symptoms associated with bacterial infections are more strongly expressed in summer, although persistent during the entire year, while petioles and midribs recovered from leaf samples [58] are also the best source for diagnosis in olive trees. Vectors should preferably be collected with sweeping nets or aspirators, while only the head of the insect should be used for DNA extraction [59].…”

Section: Disease Monitoring and Widespread Distribution Of Pathogensmentioning

confidence: 99%

Sustainable Management of Plant Quarantine Pests: The Case of Olive Quick Decline Syndrome

Luvisi

Nicolì

Bellis³

2017

Sustainability

View full text Add to dashboard Cite

Abstract:The disease outbreak of Xylella fastidiosa subsp. pauca strain CoDiRO (Complesso del Disseccamento Rapido dell'Olivo) in Salento (Apulia, South Italy) associated with severe cases of olive quick decline syndrome may represent not just a new disease paradigm, but a challenge for policy formulation and science communication in plant pathology. Plant health management can be achieved by applying a technocratic model, in which objective science is thought to directly inform policy-making, or via decisionistic or inclusive models, in which scientific considerations drive risk assessment. Each could be applied to X. fastidiosa and CoDiRO strain management, thanks to consistent literature related to pathogen/host interactions, hosts, vectors, and diagnostic tools, reviewed here. However, consensus among stakeholders seems to be necessary in order to avoid plant health management failures or gridlocks, due to environmental, economic, and social implications in the X. fastidiosa threat. Here we discuss the role of consensus in building scientific opinion, reporting different approaches of governance after severe disease outbreaks in Europe. These case studies, and the available risk analysis for Xylella strains, should drive policy formulations towards more cooperative networks.

show abstract

Seasonal Concentration of the Pierce's Disease Bacterium in Grapevine Stems, Petioles, and Leaf Veins

Cited by 90 publications

References 0 publications

Cell-cell signaling controlsXylella fastidiosainteractions with both insects and plants

Cell-cell signaling controlsXylella fastidiosainteractions with both insects and plants

Use of a Green Fluorescent Strain for Analysis ofXylella fastidiosaColonization ofVitis vinifera

Sustainable Management of Plant Quarantine Pests: The Case of Olive Quick Decline Syndrome

Contact Info

Product

Resources

About