scholarly journals The Power of Electropenetrography in Enhancing Our Understanding of Host Plant-Vector Interactions

Insects ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 407 ◽  
Author(s):  
Holly Shugart ◽  
Timothy Ebert ◽  
Frederick Gmitter ◽  
Michael Rogers
Keyword(s):  
Host Plant ◽  
Bacterial Pathogen ◽  
Resistance Mechanisms ◽  
Asian Citrus Psyllid ◽  
Citrus Species ◽  
Behavioral Differences ◽  
Plant Metabolites ◽  
Liberibacter Asiaticus ◽  
Plant Metabolite ◽  
Gas Chromatography Mass Spectroscopy

The invasive Asian citrus psyllid, Diaphorina citri (Hemiptera: Liviidae), is the primary vector of the phloem-infecting bacterium, Candidatus Liberibacter asiaticus. Candidatus L. asiaticus is the putative causal agent of Huanglongbing (HLB) disease, a destructive disease of Citrus. While many Citrus species are susceptible to D. citri probing and HLB disease, there are marked behavioral differences in D. citri probing responses and Ca. Liberibacter asiaticus infection severity among Citrus species. Using four mandarin hybrid selections and pummelo plants variably resistant to D. citri probing, oviposition, and survival, we explored probing differences using electropenetrography (EPG), conducted an oviposition and survival study, and determined host plant metabolites using gas-chromatography mass-spectroscopy (GC-MS). We found thirty-seven D. citri probing variables to be significantly different among tested mandarin selections and pummelo, in addition to differential oviposition and survivorship abilities on tested plants. We found sixty-three leaf metabolites with eight being significantly different among tested mandarin selections and pummelo. Detailed analysis of probing behavior, oviposition, survivorship, and host plant metabolite concentrations reveals the complex, layered resistance mechanisms utilized by resistant Citrus against D. citri probing. EPG is a powerful technology for screening Asian citrus psyllid resistant Citrus to elucidate host plant-vector interactions, with an aim to minimize vector probing and eliminate the spread of the bacterial pathogen, Ca. L. asiaticus.

Maternal Contribution of Candidatus Liberibacter asiaticus to Asian Citrus Psyllid (Hemiptera: Liviidae) Nymphs Through Oviposition Site Inoculation and Transovarial Transmission

2019 ◽  
Author(s):  
Alicia J Kelley ◽  
Kirsten S Pelz-Stelinski
Keyword(s):  
Vertical Transmission ◽  
Horizontal Transmission ◽  
Infected Plant ◽  
Bacterial Pathogen ◽  
Oviposition Site ◽  
Asian Citrus Psyllid ◽  
Candidatus Liberibacter Asiaticus ◽  
Infected Adult ◽  
Candidatus Liberibacter ◽  
Liberibacter Asiaticus

Abstract Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), transmits Candidatus Liberibacter asiaticus (Las), the bacterial pathogen putatively responsible for citrus huanglongbing. Multiple studies have shown psyllids acquire Las more frequently, and are more likely to inoculate susceptible plants, when they acquire Las as nymphs. Understanding the transmission of Las to nymphs is critical to the Las lifecycle. The objective of this study was to determine the transmission Las by female D. citri to their offspring. Two transmission pathways were quantified: horizontal transmission (acquisition of Las via feeding at the oviposition site) and vertical transmission (transovarial). Eggs of individual, infected females were transferred to an uninfected seedling to assess vertical transmission. In a second experiment, horizontal transmission was evaluated by replacing eggs laid by infected females with uninfected nymphs. Nymphs exposed to Las via horizontal transmission of the oviposition site were more likely to acquire Las than from vertical transmission. Las deposited in flush by an infected adult female feeding during oviposition was sufficient for infecting nymphs. Combined results of both experiments suggest that vertical transmission allows Las to spread in low amounts even when infected plant hosts are not available and that inoculation of the oviposition site provides a source of Las to developing nymphs via the plant phloem. These data support the hypothesis that transmission through infected plant material via maternal inoculation is a primary pathway of Las transmission between vector and host.

scholarly journals Effect of Adjuvants on Oxytetracycline Uptake upon Foliar Application in Citrus

Antibiotics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 677
Author(s):  
Nabil Killiny ◽  
Faraj Hijaz ◽  
Pedro Gonzalez-Blanco ◽  
Shelley E. Jones ◽  
Myrtho O. Pierre ◽  
...  
Keyword(s):  
Foliar Application ◽  
Foliar Spray ◽  
Bacterial Pathogen ◽  
Water Addition ◽  
Candidatus Liberibacter ◽  
Citrus Huanglongbing ◽  
Liberibacter Asiaticus ◽  
Trunk Injection ◽  
Citrus Leaves ◽  
Target Effects

Recently in Florida, foliar treatments using products with the antibiotics oxytetracycline and streptomycin have been approved for the treatment of citrus Huanglongbing (HLB), which is caused by the putative bacterial pathogen ‘Candidatus Liberibacter asiaticus’. Herein, we assessed the levels of oxytetracycline and ‘Ca. L. asiaticus’ titers in citrus trees upon foliar applications with and without a variety of commercial penetrant adjuvants and upon trunk injection. The level of oxytetracycline in citrus leaves was measured using an oxytetracycline ELISA kit and ‘Ca. L. asiaticus’ titer was measured using quantitative PCR. Low levels of oxytetracycline were taken up by citrus leaves after foliar sprays of oxytetracycline in water. Addition of various adjuvants to the oxytetracycline solution showed minimal effects on its uptake by citrus leaves. The level of oxytetracycline in leaves from trunk-injected trees was higher than those treated with all foliar applications. The titer of ‘Ca. L. asiaticus’ in the midrib of leaves from trees receiving oxytetracycline by foliar application was not affected after four days and thirty days of application, whereas the titer was significantly reduced in oxytetracycline-injected trees thirty days after treatment. Investigation of citrus leaves using microscopy showed that they are covered by a thick lipidized cuticle. Perforation of citrus leaf cuticle with a laser significantly increased the uptake of oxytetracycline, decreasing the titer of ‘Ca. L. asiaticus’ in citrus leaves upon foliar application. Taken together, our findings indicate that trunk injection is more efficient than foliar spray even after the use of adjuvants. Our conclusion could help in setting useful recommendations for the application of oxytetracycline in citrus to improve tree health, minimize the amount of applied antibiotic, reduce environmental exposure, and limit off-target effects.

scholarly journals Global patterns in genomic diversity underpinning the evolution of insecticide resistance in the aphid crop pest Myzus persicae

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Kumar Saurabh Singh ◽  
Erick M. G. Cordeiro ◽  
Bartlomiej J. Troczka ◽  
Adam Pym ◽  
Joanna Mackisack ◽  
...  
Keyword(s):  
Host Plant ◽  
Myzus Persicae ◽  
Resistance Mechanisms ◽  
Genomic Diversity ◽  
Resistance Mutations ◽  
Host Plant Adaptation ◽  
Repeated Evolution ◽  
Evolution Of Resistance ◽  
Selective Forces ◽  
Clonal Lines

AbstractThe aphid Myzus persicae is a destructive agricultural pest that displays an exceptional ability to develop resistance to both natural and synthetic insecticides. To investigate the evolution of resistance in this species we generated a chromosome-scale genome assembly and living panel of >110 fully sequenced globally sampled clonal lines. Our analyses reveal a remarkable diversity of resistance mutations segregating in global populations of M. persicae. We show that the emergence and spread of these mechanisms is influenced by host–plant associations, uncovering the widespread co‐option of a host-plant adaptation that also offers resistance against synthetic insecticides. We identify both the repeated evolution of independent resistance mutations at the same locus, and multiple instances of the evolution of novel resistance mechanisms against key insecticides. Our findings provide fundamental insights into the genomic responses of global insect populations to strong selective forces, and hold practical relevance for the control of pests and parasites.

scholarly journals Xanthomonas campestris Promotes Diffusible Signal Factor Biosynthesis and Pathogenicity by Utilizing Glucose and Sucrose from Host Plants

2019 ◽  
Vol 32 (2) ◽  
pp. 157-166 ◽  
Author(s):  
Chunyan Zhang ◽  
Mingfa Lv ◽  
Wenfang Yin ◽  
Tingyan Dong ◽  
Changqing Chang ◽  
...  
Keyword(s):  
Host Plant ◽  
Xanthomonas Campestris ◽  
Infection Process ◽  
Plant Metabolites ◽  
Multiple Strategies ◽  
Exogenous Addition ◽  
Diffusible Signal Factor ◽  
Signal Production ◽  
Induced Changes ◽  
Encoding Genes

The plant pathogen Xanthomonas campestris pv. campestris produces diffusible signal factor (DSF) quorum sensing (QS) signals to regulate its biological functions and virulence. Our previous study showed that X. campestris pv. campestris utilizes host plant metabolites to enhance the biosynthesis of DSF family signals. However, it is unclear how X. campestris pv. campestris benefits from the metabolic products of the host plant. In this study, we observed that the host plant metabolites not only boosted the production of the DSF family signals but also modulated the expression levels of DSF-regulated genes in X. campestris pv. campestris. Infection with X. campestris pv. campestris induced changes in the expression of many sugar transporter genes in Arabidopsis thaliana. Exogenous addition of sucrose or glucose, which are the major products of photosynthesis in plants, enhanced DSF signal production and X. campestris pv. campestris pathogenicity in the Arabidopsis model. In addition, several sucrose hydrolase–encoding genes in X. campestris pv. campestris and sucrose invertase–encoding genes in the host plant were notably upregulated during the infection process. These enzymes hydrolyzed sucrose to glucose and fructose, and in trans expression of one of these enzymes, CINV1 of A. thaliana or XC_0805 of X. campestris pv. campestris, enhanced DSF signal biosynthesis in X. campestris pv. campestris in the presence of sucrose. Taken together, our findings demonstrate that X. campestris pv. campestris applies multiple strategies to utilize host plant sugars to enhance QS and pathogenicity.

scholarly journals Interactions between the Prophage 919TP and Its Vibrio cholerae Host: Implications of gmd Mutation for Phage Resistance, Cell Auto-Aggregation, and Motility

Viruses ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2342
Author(s):  
Na Li ◽  
Yigang Zeng ◽  
Bijie Hu ◽  
Tongyu Zhu ◽  
Sine Lo Svenningsen ◽  
...  
Keyword(s):  
Bacterial Pathogen ◽  
Genomic Analysis ◽  
Resistant Mutant ◽  
Resistance Mechanisms ◽  
Phage Resistance ◽  
Comparative Genomic ◽  
Lytic Phage ◽  
O Antigen ◽  
Trade Offs ◽  
Base Pair Deletion

Prophage 919TP is widely distributed among Vibrio cholera and is induced to produce free φ919TP phage particles. However, the interactions between prophage φ919TP, the induced phage particle, and its host remain unknown. In particular, phage resistance mechanisms and potential fitness trade-offs, resulting from phage resistance, are unresolved. In this study, we examined a prophage 919TP-deleted variant of V. cholerae and its interaction with a modified lytic variant of the induced prophage (φ919TP cI-). Specifically, the phage-resistant mutant was isolated by challenging a prophage-deleted variant with lytic phage φ919TP cI-. Further, the comparative genomic analysis of wild-type and φ919TP cI--resistant mutant predicted that phage φ919TP cI- selects for phage-resistant mutants harboring a mutation in key steps of lipopolysaccharide (LPS) O-antigen biosynthesis, causing a single-base-pair deletion in gene gmd. Our study showed that the gmd-mediated O-antigen defect can cause pleiotropic phenotypes, e.g., cell autoaggregation and reduced swarming motility, emphasizing the role of phage-driven diversification in V. cholerae. The developed approach assists in the identification of genetic determinants of host specificity and is used to explore the molecular mechanism underlying phage-host interactions. Our findings contribute to the understanding of prophage-facilitated horizontal gene transfer and emphasize the potential for developing new strategies to optimize the use of phages in bacterial pathogen control.

scholarly journals The plant defense signal galactinol is specifically used as a nutrient by the bacterial pathogen Agrobacterium fabrum

2018 ◽  
Vol 293 (21) ◽  
pp. 7930-7941 ◽  
Author(s):  
Thibault Meyer ◽  
Armelle Vigouroux ◽  
Magali Aumont-Nicaise ◽  
Gilles Comte ◽  
Ludovic Vial ◽  
...  
Keyword(s):  
Competitive Advantage ◽  
Plant Defense ◽  
Higher Plants ◽  
Bacterial Pathogen ◽  
Binding Mode ◽  
Plant Colonization ◽  
Plant Metabolites ◽  
Tomato Plants ◽  
Periplasmic Binding Proteins ◽  
Nanomolar Range

The bacterial plant pathogen Agrobacterium fabrum uses periplasmic-binding proteins (PBPs) along with ABC transporters to import a wide variety of plant molecules as nutrients. Nonetheless, how A. fabrum acquires plant metabolites is incompletely understood. Using genetic approaches and affinity measurements, we identified here the PBP MelB and its transporter as being responsible for the uptake of the raffinose family of oligosaccharides (RFO), which are the most widespread d-galactose–containing oligosaccharides in higher plants. We also found that the RFO precursor galactinol, recently described as a plant defense molecule, is imported into Agrobacterium via MelB with nanomolar range affinity. Structural analyses and binding mode comparisons of the X-ray structures of MelB in complex with raffinose, stachyose, galactinol, galactose, and melibiose (a raffinose degradation product) revealed how MelB recognizes the nonreducing end galactose common to all these ligands and that MelB has a strong preference for a two-unit sugar ligand. Of note, MelB conferred a competitive advantage to A. fabrum in colonizing the rhizosphere of tomato plants. Our integrative work highlights the structural and functional characteristics of melibiose and galactinol assimilation by A. fabrum, leading to a competitive advantage for these bacteria in the rhizosphere. We propose that the PBP MelB, which is highly conserved among both symbionts and pathogens from Rhizobiace family, is a major trait in these bacteria required for early steps of plant colonization.

Cordia myxa L.1, a New Host Plant Record for Asian Citrus Psyllid, Diaphorina citri Kuwayama2

2019 ◽  
Vol 44 (1) ◽  
pp. 331 ◽  
Author(s):  
Muhammad Arshad ◽  
Muhammad Irfan Ullah ◽  
Naciye Sena Çağatay ◽  
Fatma Dikmen ◽  
Asad Abdullah ◽  
...  
Keyword(s):  
Host Plant ◽  
Asian Citrus Psyllid ◽  
Diaphorina Citri ◽  
New Host ◽  
Cordia Myxa

Detection of resistance genes from Pseudomonas aeruginosa using immunomagnetic isolation and chemiluminescence

2020 ◽  
Vol 10 (3) ◽  
pp. 412-418
Author(s):  
Fei Xu ◽  
Cheng Chen ◽  
Xing Li ◽  
Bo Zhang
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Resistance Genes ◽  
High Efficiency ◽  
Bacterial Pathogen ◽  
Resistance Mechanisms ◽  
Clinical Samples ◽  
Specific Gene ◽  
Beta Lactamases ◽  
Immunomagnetic Isolation ◽  
Encoding Gene

Pseudomonas aeruginosa (P. aeruginosa) is a common opportunistic and nosocomial bacterial pathogen. Various multi-resistance mechanisms present across numerous P. aeruginosa strains counteract conventional antimicrobial therapy, thereby becoming a great challenge. This study aimed to establish the application of immunomagnetic isolation and chemiluminescence to detect the presence of extended spectra of β-lactamases encoding genes: blaTEM and blaVEB; metallo-beta-lactamases encoding gene: blaVIM; aminoglycoside modifying enzymes encoding gene: aac(6)II, ant(3)I; and the specific gene for P. aeruginosa, gyrB. P. aeruginosa was specifically selected using the immunomagnetic nanoparticles (IMNPs) in the six parallel bacterial plates counting, proving that they are reliable. Then, the high efficiency of IMNPs@Probes in targeting the resistance genes of P. aeruginosa was demonstrated using the results of chemiluminescent intensities of blaTEM, blaVEB, blaVIM aac(6)II, ant(3)I, and gyrB (more than 10 times higher than that of the control). Sixty-eight in situ clinical samples were tested for the presence of these resistance genes, and one more blaTEM and three more blaVIM individuals were detected using this method compared to the traditional PCR. Thus, the application of our method in clinical screening is specific, accurate, and reliable, and it could be useful in the administration of appropriate treatment.

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