Development Of Bacterial Canker Research Articles

Distribution and damage of bacterial canker on lemon bushes in the conditions of the Southern part of Azerbaijan

This paper summarises and presents the results of two-year (2020–2021) field and laboratory studies on the spread and harmfulness of bacterial canker of citrus crops (Xanthomonas citri (Hasse) Dowson.) on mid-ripening lemon cultivars (Citrus limon L.). Experimental field research conducted by us in 2020–2021. It has been established that bacterial canker (Xanthomonas citri) is found mainly on lemon bushes (Citrus limon L.). The pathogen also causes canker (Xanthomonas citri) on kinkans (Fortunella margarita (Lour) Swingle.), poncirus (Poncirus (L.) Raf.), lime (Cirtus aurantiifolia (Christm.) Swingle.). Japanese cultivars of oranges (Citrus sinensis (L.) Osbeck.) and citron (Citrus medica L.) are distinguished by significant tolerance. The most resistant are tangerines (Cirtus reticulata Blanco.) – they are almost not affected by bacterial canker (Xanthomonas citri). We have established environmental factors that contribute to the wide spread and development of bacterial canker (Xanthomonas citri) on lemon bushes in the southern part of Azerbaijan. The main indicators of the harmfulness of bacterial canker (Xanthomonas citri) have been identified. The potential for the death of canker-infected lemon fruits has been established. The characteristic features of external and internal signs of the disease were established. A scheme for combating bacterial canker (Xanthomonas citri) has been developed, and the optimal concentration of fungicides that retard the growth and development of pathogens has also been established. Photographs of bacterial canker (Xanthomonas citri) damage to lemon fruits are presented.

Advances in the Characterization of the Mechanism Underlying Bacterial Canker Development and Tomato Plant Resistance

Bacterial canker caused by the Gram-positive actinobacterium Clavibacter michiganensis is one of the most serious bacterial diseases of tomatoes, responsible for 10–100% yield losses worldwide. The pathogen can systemically colonize tomato vascular bundles, leading to wilting, cankers, bird’s eye lesions, and plant death. Bactericidal agents are insufficient for managing this disease, because the pathogen can rapidly migrate through the vascular system of plants and induce systemic symptoms. Therefore, the use of resistant cultivars is necessary for controlling this disease. We herein summarize the pathogenicity of C. michiganensis in tomato plants and the molecular basis of bacterial canker pathogenesis. Moreover, advances in the characterization of resistance to this pathogen in tomatoes are introduced, and the status of genetics-based research is described. Finally, we propose potential future research on tomato canker resistance. More specifically, there is a need for a thorough analysis of the host–pathogen interaction, the accelerated identification and annotation of resistance genes and molecular mechanisms, the diversification of resistance resources or exhibiting broad-spectrum disease resistance, and the production of novel and effective agents for control or prevention. This review provides researchers with the relevant information for breeding tomato cultivars resistant to bacterial cankers.

Systematic Analysis and Functional Validation of Citrus Pectin Acetylesterases (CsPAEs) Reveals that CsPAE2 Negatively Regulates Citrus Bacterial Canker Development.

The present study was designed to serve as a comprehensive analysis of Citrus sinensis (C. sinensis) pectin acetylesterases (CsPAEs), and to assess the roles of these PAEs involved in the development of citrus bacterial canker (CBC) caused by Xanthomonas citri subsp. citri (Xcc) infection. A total of six CsPAEs were identified in the genome of C. sinensis, with these genes being unevenly distributed across chromosomes 3, 6, and 9, and the unassembled scaffolds. A subset of CsPAEs were found to be involved in responses to Xcc infection. In particular, CsPAE2 was identified to be associated with such infections, as it was upregulated in CBC-susceptible variety Wanjincheng and inversely in CBC-resistant variety Calamondin. Transgenic citrus plants overexpressing CsPAE2 were found to be more susceptible to CBC, whereas the silencing of this gene was sufficient to confer CBC resistance. Together, these findings provide evolutionary insights into and functional information about the CsPAE family. This study also suggests that CsPAE2 is a potential candidate gene that negatively contributes to bacterial canker disease and can be used to breed CBC-resistant citrus plants.

Temperature at the early stages of Clavibacter michiganensis subsp. michiganensis infection affects bacterial canker development and virulence gene expression

Clavibacter michiganensis subsp. michiganensis (Cmm), the causal agent of bacterial canker and wilt, causes severe economic losses in tomato net‐houses and greenhouses worldwide. In this study, seedlings which were transplanted and inoculated monthly over 2 years wilted and died earlier in the spring (21–24°C) and autumn (18–23°C) than in the winter (15–18°C) and summer (28–31°C): T50 (the time taken for 50% of the plants to wilt or die) was 2 and 3–4 months after inoculation, respectively. A highly significant correlation was found between the average temperatures during the first month after inoculation and T50; the shortest T50 mortality (70 days) was observed for an average temperature of 26°C. Expression of virulence genes (pat‐1, celA, chpC and ppaA) by Cmm was higher in plants inoculated in the spring than in those inoculated in the summer. In another set of experiments, seedlings were inoculated and maintained in controlled‐environment growth chambers for 2 weeks. Subsequently, they were transplanted and maintained in commercial‐type greenhouses for 4–5 months. The temperatures prevailing in the first 48 h after inoculation were found to affect Cmm population size and virulence gene expression and to have season‐long effects on bacterial canker development.

Inhibitory activities of venom alkaloids of Red Imported Fire Ant against Clavibacter michiganensis subsp. michiganensis in vitro and the application of piperidine alkaloids to manage symptom development of bacterial canker on tomato in the greenhouse

Tomato bacterial canker caused by Clavibacter michiganensis subsp. michiganensis (CMM) is a highly destructive disease that has caused major economic losses in tomato production worldwide. In seeking disease management alternatives, the inhibitory activity of alkaloids extracted from the Red Imported Fire Ant was studied in the laboratory and the greenhouse. Piperidine and piperideine alkaloids each significantly inhibited CMM growth on nutrient agar plates. The inhibitory activity of piperidine alkaloids was stable at 4 ° C and 22 ° C for 12 weeks and at 54 ° C for 4 weeks. The growth of CMM was negatively correlated with the concentration of piperidine alkaloids in nutrient broth. In the greenhouse, piperidine alkaloids also significantly reduced the symptom development on two tomato cultivars, Better Boy and DRK7018F1. This is the first demonstration that piperidine and piperideine alkaloids from the Red Imported Fire Ant are highly inhibitory against a plant-pathogenic bacterium, viz. CMM. Piperidine alkaloids could provide satisfactory management of CMM bacterial canker on tomato seedlings in the greenhouse. Our findings may lead to the development of a new group of bactericides.

Influence of Stem Diameter, Water Content, and Freezing-Thawing on Bacterial Canker Development in Excised Stems of Dormant Stone Fruit

ABSTRACT In excised dormant stems of peach (Prunus persica), prune (Prunus domestica), and almond (Prunus dulcis), stem diameter, stem hydration, and freezing-thawing influenced the extent of infection caused by Pseudomonas syringae pv. syringae. Bacterial lesion length increased with increasing stem diameter, demonstrating the need to account for the effects of stem diameter when lesion length data are analyzed. Lesion length increased or decreased with stem hydration or dehydration, respectively. However, tissue water content was not a good indicator of tissue susceptibility to infection by P. syringae pv. syringae, as larger diameter stems had larger lesions and lower water content than did smaller diameter stems. After freezing at -5 degrees C for 12 to 24 h, inoculations made during the thawing process produced significantly larger lesions than did inoculations performed before freezing or after thawing. These results support the hypothesis that the increased susceptibility to bacterial canker that is associated with noninjurious freezing is a result of the increased passive spread of bacteria through water redistribution when inoculation is performed during the thawing process. Plant tissue water relationship characteristics that can influence water movement during freezing and thawing may be an important component of bacterial canker development in stone fruit trees.

Rating Scales to Assess Cold Injury and Bacterial Canker Development in Peach Trees in the Field

Abstract Visual rating scales were developed for evaluating tissue injury in peach trees [Prunus persica (L.) Batsch] in the orchard due to cold/winter temperatures and bacterial canker (Pseudomonas syringae van Hall) development. The numerical ratings on a scale of 1 to 9 separately describe key stages of damage and its severity due to cold and bacterial canker and are portrayed pictorially for clarity. Accurate estimation of tree status at very early stages of injury and good correlation with ultimate tree survival have been possible through the use of these rating scales. This information has been incoporated in the data collection for a regional research project dealing with the development and evaluation of rootstocks for peach in the southern United States and also is under consideration for use in another regional project involving peach in addition to apple, pear, and cherry.

The effect of cold on development of bacterial canker in apricot trees infected with Pseudomonas syringae pv. syringae

There is a close association between the development of bacterial canker diseases of apricot trees caused by Pseudomonas syringae pv. syringae and low winter temperatures. Laboratory experiments with apricot stem pieces showed that neither bacterial infection, nor below freezing temperatures, alone cause phloem necrosis and disease only occurs when bacterial infections precede exposure of stem pieces to −5°C by 5 to 10 days. Multiplication of the pathogen prior to freezing utilizes the sugars in the phloem tissue and results in a 19 to 48% reduction in sugar levels. As a consequence of the lowered sugar content the infected phloem and cambium become sensitive to frost injury and when such tissues are stressed by frost they become even more susceptible to the pathogen so that bacterial numbers increase to 10 6 to 10 7 cells cm −2 phloem tissue.

Effect of Ring and Pin Nematodes on the Development of Bacterial Canker and Cytospora Canker in Young French Prune Trees

Effect of Ring and Pin Nematodes on the Development of Bacterial Canker and Cytospora Canker in Young French Prune Trees

Evaluation of Different Methods to Assess Cold Hardiness of Peach Trees1

Abstract The reliability, capability to predict survival, and convenience of 5 cold hardiness tests — triphenyl tetrazolium chloride reduction (TTC), electrolytic conductance (EC), ninhydrin-reactive compounds (NRC), trunk cambial browning (TCB), and bacterial canker development (BCD) — were evaluated using previous season's twigs of ‘Redhaven’ peach (Prunus persica (L.) Batsch) during the 1976-77 dormancy season. TTC, NRC, and EC were all significantly correlated with TCB as well as percent tree survival (PTS) in the field, and thus proved to be quantitative, reliable and capable of predicting survival at a later date. No statistical correlation was found between BCD and other hardiness tests.

Relation of Age of Plants, Temperature, and Inoculum Concentration to Bacterial Canker Development in Resistant and Susceptible Lycopersicon spp.

Relation of Age of Plants, Temperature, and Inoculum Concentration to Bacterial Canker Development in Resistant and Susceptible Lycopersicon spp.

Studies on the mode of action and biogenesis of the phytotoxin syringomycin

Syringomycin, a polypeptide phytotoxin produced by Pseudomonas syringae, is involved in the disease development of bacterial canker of peach. Pathogenicity tests in several plant species indicated that disease development was not always related to the production of syringomycin on agar medium either by isolates of P. syringae, or other isolates such as P. mors-prunorum. At sublethal doses syringomycin inhibited uridylic acid incorporation in Geotrichum candidum but stimulated thymidylic acid incorporation. Syringomycin was found to inhibit tobacco mosaic virus local-lesion formation in tobacco and inhibit synthesis of the RNA phage MS2 in Escherichia coli. The nature of this inhibition was not completely determined, but for MS2 it appeared to involve an inhibition of phage attachment. Droplets of aqueous syringomycin solutions had a lower contact angle with polystyrene plastic than did water; this effect on surface tension indicated a possible membrane action for syringomycin. Further experiments revealed that syringomycin caused rapid hemolysis of rabbit red blood cells, and that leakage of 260 nm absorbing materials occurred from cells of G. candidum treated with syringomycin. Electron micrographs of syringomycin-treated G. candidum cells indicated that massive disruption of membrane integrity occurred with lethal doses, and that membrane abnormalities occurred at sublethal doses. Microautoradiography with 14C-labeled syringomycin indicated that syringomycin was concentrated mainly over the plasmalemma and nuclear membranes. Inhibition of syringomycin activity by sterols and certain phospholipids in agar media indicated that the binding of syringomycin on the membranes could involve membrane lipids. Calcium and magnesium ions also inhibited syringomycin activity. Rabbit antisera for cell wall material from syringomycin-producing and non-producing isolates of P. syringae reacted strongly with syringomycin; this indicated that syringomycin was structurally related to cell wall materials. It appears that syringomycin is a haptenic group of a larger cell wall antigenic substance and that syringomycin may be a product of the cell wall metabolism of P. syringae. The primary action of syringomycin appears to be a rapid detergent-like lysis of cellular membranes. The action of syringomycin on nucleic acids is probably secondary to its action on membranes.

Factors affecting development of the bacterial canker of stone fruits

Abstract does not appear. First page follows. Bacterial canker of Prunus, caused by Phytomonas cerasi (Griffin) Bergey et al.,3 has been studied by the writer, with some interruptions, for the past seven years. Certain phases, including the serious limb-canker stage, have been described from time to time (15)-(18).4 This article discusses how various factors affect canker activity after infection is established. Sequence of Events in Development of Bacterial Canker Under Orchard Conditions Stages in the Activity of Cankers.—Although a general description of canker development is in print (16), later discussion will be clarified if the sequence of changes during canker activity is described in detail at this point. An established canker will be taken as an example, and its development from early autumn to summer will be followed. This canker, present in the tree in early autumn, arose from an infection the previous winter or spring. It is a roughly elliptical area of dead bark, its margins grading away either into healthy tissue or, more frequently, into a series of reddish-brown streaks, which form a zone sometimes several inches wide at the apices of the necrotic center. In early autumn the canker appears inactive, the tissue involved being dry with no signs of water-soaking along the margins. The lateral margins of the canker may be delimited by a roll of new tissue, the outer layers of which are essentially callus in nature. The nature of the reddish-brown streaks present at the apical margins is discussed in a later section. Nothing further will be said about them here except that they are called “dormant streaks” to distinguish them from the less noticeable, dull-brown, water-soaked streaks occurring at the margins of active cankers. The designations dormant and active are used because such streaks are characteristic, respectively, of dormant (or quiescent) and active cankers.