scholarly journals Salicylic acid mediated immune response of Citrus Sinensis to varying frequencies of herbivory and pathogen inoculation

2020 ◽  
Author(s):  
Freddy Ibanez ◽  
Joon Hyuk Suh ◽  
Yu Wang ◽  
Monique Rivera ◽  
Mamoudou Setamou ◽  
...  
Keyword(s):  
Immune Response ◽  
Salicylic Acid ◽  
Defense Response ◽  
Citrus Sinensis ◽  
Sweet Orange ◽  
Defense Responses ◽  
Insect Vector ◽  
Diaphorina Citri ◽  
Liberibacter Asiaticus

AbstractPlant immunity against pathogens and pests is comprised of complex mechanisms orchestrated by signaling pathways regulated by plant hormones [Salicylic acid (SA) and Jasmonic acid (JA)]. Investigations of plant immune response to phytopathogens and phloem-feeders have revealed that SA plays a critical role in reprogramming of the activity and/or localization of transcriptional regulators via post-translational modifications. We explored the contributing effects of herbivory by a phytopathogen vector [Asian citrus psyllid, Diaphorina citri] and pathogen [Candidatus Liberibacter asiaticus (CLas)] infection on response of sweet orange [Citrus sinensis (L.) Osbeck] using manipulative treatments designed to mimic the types of infestations/infections that citrus growers experience when cultivating citrus in the face of Huanglongbing (HLB) disease. A one-time (7 d) inoculation access period with CLas-infected vectors caused SA-associated upregulation of PR-1, stimulating defense response after a long period of infection without herbivory (270 and 330 days). In contrast, while repeated (monthly) ‘pulses’ of 7 d psyllid feeding injury stimulated immunity in CLas-infected citrus by increasing [SA] in leaves initially (up to 120 d), long-term (270 and 330 days) repeated herbivory caused [SA] to decrease coincident with upregulation of genes associated with SA metabolism (BMST and DMR6). Similarly, transcriptional responses and metabolite (SA and its analytes) accumulation in citrus exposed to a continuously reproducing population of D. citri exhibited a transitory upregulation of genes associated with SA signaling at 120 days and a posterior downregulation after long-term psyllid (adults and nymphs) feeding (270 and 330 days). Herbivory played an important role in regulation of SA accumulation in mature leaves of C. sinensis, whether or not those trees were coincidentally infected with CLas. Our results indicate that prevention of feeding injury inflicted by D. citri from the tritrophic interaction may allow citrus plants to better cope with the consequences of CLas infection, highlighting the importance of vector suppression as a component of managing this cosmopolitan disease.Author SummaryWe explored tritrophic interactions among an insect vector (Diaphorina citri) – phytopathogen (Candidatus Liberibacter asiaticus) – and cultivated fruit crop [sweet orange, Citrus sinensis (L) Osbeck]. Transcriptional and metabolic responses of plants were analyzed over an extended time-course of disease progression after various frequencies of herbivore feeding and durations of pathogen infection using manipulative treatments designed to mimic the types of infestations/infections that citrus growers experience when cultivating citrus in the presence of the devastating citrus disease, huanglongbing. We found that in the absence of coincident psyllid feeding damage, citrus trees could mount a defense response against the pathogen by activating the salicylic acid (SA) pathway. Repeated, monthly ‘pulses’ of herbivory led to pronounced stimulation of SA transcription that was coincident with diminished pathogen titers in plants. Although insect injury initially activated SA-dependent defense responses, continuous and/or long-term (≥ 270 d) herbivory shut down PR-1-dependent defense responses against the pathogen. Our results provide a mechanism explaining how vector suppression contributes to maintaining health of cultivated citrus in areas where huanglongbing is endemic. Our results also point to specific gene targets that may yield novel genotypes expressing tolerance against CLas after appropriate manipulations.

Prevalent transmission of 'Candidatus Liberibacter asiaticus’ over ‘Ca. Liberibacter americanus’ in a long-term controlled environment

2021 ◽  
Author(s):  
Maria Cândida de Godoy Gasparoto ◽  
Isabela Vescove Primiano ◽  
Renato Bassanezi ◽  
Silvia Afonseca Lourenço ◽  
Luiz Montesino ◽  
...  
Keyword(s):  
Sweet Orange ◽  
Insect Vector ◽  
Diaphorina Citri ◽  
Candidatus Liberibacter Asiaticus ◽  
Candidatus Liberibacter ◽  
Citrus Huanglongbing ◽  
Liberibacter Asiaticus ◽  
Citrus Orchards ◽  
Test Plants

In Brazil, citrus huanglongbing (HLB) is associated with ‘Candidatus Liberibacter americanus’ (CLam) and ‘Ca. Liberibacter asiaticus’ (CLas). However, there are few studies about HLB epidemiology when both Liberibacter spp. and its insect vector, the Asian citrus psyllid (ACP, Diaphorina citri), are present. The objective of this work was to compare the transmission of HLB by ACP when both CLam and CLas are present as primary inoculum. Two experiments were performed under screenhouse conditions from April 2008 to January 2012 (experiment 1) and from February 2011 to December 2015 (experiment 2). The experiments were carried out with sweet orange plants infected with CLam or CLas as inoculum source surrounded by sweet orange healthy plants. One hundred Liberibacter-free adult psyllids were monthly confined to the source of inoculum plants for 7 days with subsequent free movement inside the screenhouse. Fortnightly, nymphs and adults of psyllids were monitored. Psyllid and leaf samples were collected periodically for Liberibacter detection by PCR or qPCR. CLas was detected more frequently than CLam in both psyllid and leaf samples. No mixed infections were detected in the psyllids. A clear prevalence of CLas over CLam was observed in both experiments. The final HLB incidences were 16.7 and 14.5% of Liberibacter-positive test plants, and CLas was detected in 92.3 and 93.1% of these infected plants. Mixed infection was observed only in 3.8% of infected test plants in experiment 1. These results endorse the shift in the prevalence of CLam to CLas observed in citrus orchards of São Paulo, Brazil.

scholarly journals Salicylic acid mediated immune response of Citrus sinensis to varying frequencies of herbivory and pathogen inoculation

2022 ◽  
Vol 22 (1) ◽  
Author(s):  
Freddy Ibanez ◽  
Joon Hyuk Suh ◽  
Yu Wang ◽  
Monique Rivera ◽  
Mamoudou Setamou ◽  
...  
Keyword(s):  
Immune Response ◽  
Salicylic Acid ◽  
Citrus Sinensis ◽  
Plant Immunity ◽  
Critical Role ◽  
Transcriptional Responses ◽  
The Face ◽  
Inoculation Access Period ◽  
Citrus Leaves

Abstract Background Plant immunity against pathogens and pests is comprised of complex mechanisms orchestrated by signaling pathways regulated by plant hormones [Salicylic acid (SA) and Jasmonic acid (JA)]. Investigations of plant immune response to phytopathogens and phloem-feeders have revealed that SA plays a critical role in reprogramming of the activity and/or localization of transcriptional regulators via post-translational modifications. We explored the contributing effects of herbivory by a phytopathogen vector [Asian citrus psyllid, Diaphorina citri] and pathogen [Candidatus Liberibacter asiaticus (CaLas)] infection on response of sweet orange [Citrus sinensis (L.) Osbeck] using manipulative treatments designed to mimic the types of infestations/infections that citrus growers experience when cultivating citrus in the face of Huanglongbing (HLB) disease. Results A one-time (7 days) inoculation access period with CaLas-infected vectors caused SA-associated upregulation of PR-1, stimulating defense response after a long period of infection without herbivory (270 and 360 days). In contrast, while repeated (monthly) ‘pulses’ of 7 day feeding injury by psyllids stimulated immunity in CaLas-infected citrus by increasing SA in leaves initially (up to 120 days), long-term (270 and 360 days) repeated herbivory caused SA to decrease coincident with upregulation of genes associated with SA metabolism (BMST and DMR6). Similarly, transcriptional responses and metabolite (SA and its analytes) accumulation in citrus leaves exposed to a continuously reproducing population of D. citri exhibited a transitory upregulation of genes associated with SA signaling at 120 days and a posterior downregulation after long-term psyllid (adults and nymphs) feeding (270 and 360 days). Conclusions Herbivory played an important role in regulation of SA accumulation in mature leaves of C. sinensis, whether or not those trees were coincidentally infected with CaLas. Our results indicate that prevention of feeding injury inflicted by D. citri from the tritrophic interaction may allow citrus plants to better cope with the consequences of CaLas infection, highlighting the importance of vector suppression as a component of managing this cosmopolitan disease.

Probing the application of OmpA-derived peptides to disrupt the acquisition of ‘Candidatus Liberibacter asiaticus’ by Diaphorina citri

2021 ◽  
Author(s):  
Marcus Vinicius Merfa e Silva ◽  
Eduarda Regina Fischer ◽  
Mariana de Souza e Silva ◽  
Carolina Sardinha Francisco ◽  
Helvécio Coletta-Filho ◽  
...  
Keyword(s):  
Control Strategies ◽  
Insect Vector ◽  
Diaphorina Citri ◽  
Candidatus Liberibacter Asiaticus ◽  
In Planta ◽  
Host Interaction ◽  
Vector Population ◽  
Candidatus Liberibacter ◽  
Liberibacter Asiaticus ◽  
Bacterial Outer Membrane

Huanglongbing (HLB) is currently the most devastating disease of citrus worldwide. Both bacteria ‘Candidatus Liberibacter asiaticus’ (CLas) and ‘Ca. Liberibacter americanus’ (CLam) are associated with HLB in Brazil, but with a strong prevalence of CLas over CLam. Conventionally, HLB management focuses on controlling the insect vector population (Diaphorina citri; also known as Asian citrus psyllid – ACP) by spraying insecticides, an approach demonstrated to be mostly ineffective. Thus, development of novel more efficient HLB control strategies is required. The multifunctional bacterial outer membrane protein OmpA is involved in several molecular processes between bacteria and their hosts and has been suggested as a target for bacterial control. Curiously, OmpA is absent in CLam in comparison to CLas, suggesting a possible role on host-interaction. Therefore, in the current study, we have treated ACPs with different OmpA-derived peptides aiming to evaluate the acquisition of CLas by the insect vector. Treatment of psyllids with 5 µM of Pep1, Pep3, Pep5 and Pep6 in artificial diet significantly reduced the acquisition of CLas, while increasing the concentration of Pep5 and Pep6 to 50 µM abolished this process. In addition, in planta treatment with 50 µM of Pep6 also significantly decreased the acquisition of CLas and sweet orange plants stably absorbed and maintained this peptide for as long as three months post the final application. Together, our results demonstrate the promising use of OmpA-derived peptides as a novel biotechnological tool to control CLas.

A Review of Huanglongbing (Citrus Greening) Management in Citrus Using Nutritional Approaches in China

2011 ◽  
Vol 12 (1) ◽  
pp. 24 ◽  
Author(s):  
Yulu Xia ◽  
Gecheng Ouyang ◽  
Ronald A. Sequeira ◽  
Yu Takeuchi ◽  
Ignacio Baez ◽  
...  
Keyword(s):  
Nutrient Management ◽  
Field Survey ◽  
Cultural Practices ◽  
Sweet Orange ◽  
Asian Citrus Psyllid ◽  
Diaphorina Citri ◽  
Candidatus Liberibacter Asiaticus ◽  
Candidatus Liberibacter ◽  
Citrus Maxima ◽  
Liberibacter Asiaticus

The Asian form of huanglongbing (HLB) is caused by ‘Candidatus Liberibacter asiaticus (Las),’ a phloem-limited bacterium transmitted by the Asian citrus psyllid, Diaphorina citri Kuwayama. Nutrient management, together with other cultural practices such as pruning and irrigation, for mitigation of the disease has been practiced in China for many years. Our literature review, field survey, and interviews with Chinese scientists and growers indicate that these cultural practices were generally ineffective for the disease management. However, a nutritional approach in conjunction with other cultural practices such as irrigation can maintain grove productivity for a certain time depending on the type of citrus species/cultivars, the age of the trees, the propagation method of the plants, the Asian citrus psyllid (ACP) (Diaphorina citri Kuwayama) population, and other factors. Symptomatic mature pommelo (Citrus maxima Merr) and sweet orange (C. sinensis L. Osbeck) plants can commonly survive and maintain a certain level of productivity for an additional 4 to 5 years, even longer assuming vigorous ACP control. Accepted for publication 27 June 2011. Published 3 October 2011.

scholarly journals Metabolic Profiling of Hybrids Generated from Pummelo and Citrus latipes in Relation to Their Attraction to Diaphorina citri, the Vector of Huanglongbing

Metabolites ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 477
Author(s):  
Nabil Killiny ◽  
Shelley E. Jones ◽  
Faraj Hijaz ◽  
Abdelaziz Kishk ◽  
Yulica Santos-Ortega ◽  
...  
Keyword(s):  
Leaf Morphology ◽  
Bacterial Pathogen ◽  
Gas Chromatography Mass Spectrometry ◽  
Insect Vector ◽  
Diaphorina Citri ◽  
Metabolomic Analysis ◽  
Citrus Industry ◽  
Candidatus Liberibacter ◽  
Citrus Maxima ◽  
Liberibacter Asiaticus

The citrus industry at present is severely affected by huanglongbing disease (HLB). HLB is caused by the supposed bacterial pathogen “Candidatus Liberibacter asiaticus” and is transmitted by the insect vector, the Asian citrus psyllid, Diaphorina citri Kuwayama. Developing new citrus hybrids to improve HLB management is much needed. In this study, we investigated the metabolomic profiles of three new hybrids produced from the cross of C2-5-12 Pummelo (Citrus maxima (L.) Osbeck) × pollen from Citrus latipes. The hybrids were selected based on leaf morphology and seedling vigor. The selected hybrids exhibited compact and upright tree architecture as seen in C. latipes. Hybrids were verified by simple sequence repeat markers, and were subjected to metabolomic analysis using gas chromatography-mass spectrometry. The volatile organic compounds (VOCs) and polar metabolites profiling also showed that the new hybrids were different from their parents. Interestingly, the levels of stored VOCs in hybrid II were higher than those observed in its parents and other hybrids. The level of most VOCs released by hybrid II was also higher than that released from its parents. Additionally, the preference assay showed that hybrid II was more attractive to D. citri than its parents and other hybrids. The leaf morphology, compact and upright architecture of hybrid II, and its attraction to D. citri suggest that it could be used as a windbreak and trap tree for D. citri (double duty), once its tolerance to HLB disease is confirmed. Our results showed that metabolomic analysis could be successfully used to understand the biochemical mechanisms controlling the interaction of D. citri with its host plants.

scholarly journals Near-Complete Genome Sequences of a Wolbachia Strain Isolated from Diaphorina citri Kuwayama (Hemiptera: Liviidae)

2020 ◽  
Vol 9 (35) ◽  
Author(s):  
Surendra Neupane ◽  
Sylvia I. Bonilla ◽  
Andrew M. Manalo ◽  
Kirsten S. Pelz-Stelinski
Keyword(s):  
Complete Genome ◽  
Wolbachia Strain ◽  
Insect Vector ◽  
Diaphorina Citri ◽  
Genome Sequences ◽  
Content Type ◽  
Liberibacter Asiaticus

ABSTRACT Wolbachia strains are one of three endosymbionts associated with the insect vector of “Candidatus Liberibacter asiaticus,” Diaphorina citri Kuwayama (Hemiptera: Liviidae). We report three near-complete genome sequences of samples of Wolbachia from D. citri (wDi), with sizes of 1,518,595, 1,542,468, and 1,538,523 bp.

Temporal Dynamics of Candidatus Liberibacter asiaticus Titer in Mature Leaves from Citrus sinensis cv Valencia Are Associated with Vegetative Growth

2019 ◽  
Vol 113 (2) ◽  
pp. 589-595 ◽  
Author(s):  
Freddy Ibanez ◽  
Lukasz L Stelinski
Keyword(s):  
Vegetative Growth ◽  
Citrus Sinensis ◽  
Temporal Dynamics ◽  
Critical Role ◽  
Insect Vector ◽  
In Planta ◽  
Mature Leaves ◽  
Candidatus Liberibacter ◽  
Liberibacter Asiaticus ◽  
The Impact

Abstract Huanglongbing, a highly destructive disease of citrus species, is associated with a fastidious, gram-negative, phloem-limited bacteria (Candidatus Liberibacter spp.). In Florida, the causative agent of Huanglongbing (HLB) is C. Liberibacter asiaticus (CLas) and it is transmitted by the insect vector, Asian citrus psyllid (Diaphorina citri Kuwayama). Previous investigations have revealed systemic infection of CLas with an erratic and uneven distribution of pathogen in tree phloem. However, previous investigations did not consider the potential impact of plant vegetative growth on presence/absence of CLas in planta. Our objectives were to determine: 1) the effect of vegetative growth of Citrus sinensis (L.) Osbeck cv Valencia on detection of CLas in mature leaves, and 2) the impact of CLas inoculation frequency on progression of CLas titer in citrus leaves through the first year of infection. Temporal dynamics of CLas detection were associated with vegetative flush growth. Surprisingly, there was no difference in CLas titer detected between plants exposed to infected vectors for a one-time 7 d inoculation access period, as compared with plants exposed to continuously breeding CLas-infected insects over the course of an entire year of plant infection. Our results suggest that the CLas bacterium is transported through phloem during annual movement of carbon compounds needed for vegetative plant growth, including transportation from roots to mature leaves. These results highlight the importance of vegetative growth on temporal dynamics of CLas in citrus, and suggest a critical role of the sink-source interaction on presence/absence of CLas in leaves.

Detection of Candidatus Liberibacter asiaticus from Wampee (Clausena lansium Skeels) by Nested PCR

2007 ◽  
Vol 8 (1) ◽  
pp. 53 ◽  
Author(s):  
Xiaoling Deng ◽  
Gen Zhou ◽  
Huaping Li ◽  
Jianchi Chen ◽  
Edwin L. Civerolo
Keyword(s):  
Nested Pcr ◽  
Southern China ◽  
Diaphorina Citri ◽  
Candidatus Liberibacter Asiaticus ◽  
Term Survival ◽  
Disease Vector ◽  
Candidatus Liberibacter ◽  
Liberibacter Asiaticus ◽  
Citrus Orchards

Wampee (Clausena lansium Skeels) is native to southern China and Southeast Asia. Wampee trees are attractive, with grape-like fruits and a muscat taste and are popular in home gardens. Like other members of Rutaceae, wampee has long been suspected to have yellow shoot disease or Huanglongbing (HLB) and Diaphorina citri, the disease vector, was capable of a long-term survival on Wampee. The authors recommend that eradication of wampee trees surrounding citrus orchards should be part of the overall management of citrus HLB. Accepted for publication 20 December 2007. Published 19 April 2007.

scholarly journals Signaling Crosstalk between Salicylic Acid and Ethylene/Jasmonate in Plant Defense: Do We Understand What They Are Whispering?

2019 ◽  
Vol 20 (3) ◽  
pp. 671 ◽  
Author(s):  
Ning Li ◽  
Xiao Han ◽  
Dan Feng ◽  
Deyi Yuan ◽  
Li-Jun Huang
Keyword(s):  
Salicylic Acid ◽  
Signaling Pathways ◽  
Pseudomonas Syringae ◽  
Defense Response ◽  
Systemic Acquired Resistance ◽  
Acquired Resistance ◽  
Defense Responses ◽  
Host Cells ◽  
Defense Gene Expression ◽  
Signaling Crosstalk

During their lifetime, plants encounter numerous biotic and abiotic stresses with diverse modes of attack. Phytohormones, including salicylic acid (SA), ethylene (ET), jasmonate (JA), abscisic acid (ABA), auxin (AUX), brassinosteroid (BR), gibberellic acid (GA), cytokinin (CK) and the recently identified strigolactones (SLs), orchestrate effective defense responses by activating defense gene expression. Genetic analysis of the model plant Arabidopsis thaliana has advanced our understanding of the function of these hormones. The SA- and ET/JA-mediated signaling pathways were thought to be the backbone of plant immune responses against biotic invaders, whereas ABA, auxin, BR, GA, CK and SL were considered to be involved in the plant immune response through modulating the SA-ET/JA signaling pathways. In general, the SA-mediated defense response plays a central role in local and systemic-acquired resistance (SAR) against biotrophic pathogens, such as Pseudomonas syringae, which colonize between the host cells by producing nutrient-absorbing structures while keeping the host alive. The ET/JA-mediated response contributes to the defense against necrotrophic pathogens, such as Botrytis cinerea, which invade and kill hosts to extract their nutrients. Increasing evidence indicates that the SA- and ET/JA-mediated defense response pathways are mutually antagonistic.

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