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 Development on Infected Citrus over Generations Increases Vector Infection by ‘Candidatus Liberibacter Asiaticus in Diaphorina citri’

Insects ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 469
Author(s):  
Inaiara de Souza Pacheco ◽  
Diogo Manzano Galdeano ◽  
João Roberto Spotti Lopes ◽  
Marcos Antonio Machado
Keyword(s):  
Management Strategies ◽  
Fourth Generation ◽  
Diaphorina Citri ◽  
Candidatus Liberibacter Asiaticus ◽  
Candidatus Liberibacter ◽  
Citrus Huanglongbing ◽  
Liberibacter Asiaticus ◽  
Citrus Orchards ◽  
Vector Efficiency ◽  
Control And Eradication

‘Candidatus Liberibacter asiaticus’ (CLas) is a major causal agent of citrus Huanglongbing (HLB), which is transmitted by Asian citrus psyllid (ACP), Diaphorina citri, causing severe losses in various regions of the world. Vector efficiency is higher when acquisition occurs by ACP immature stages and over longer feeding periods. In this context, our goal was to evaluate the progression of CLas population and infection rate over four ACP generations that continuously developed on infected citrus plants. We showed that the frequency of CLas-positive adult samples increased from 42% in the parental generation to 100% in the fourth generation developing on CLas-infected citrus. The bacterial population in the vector also increased over generations. This information reinforces the importance of HLB management strategies, such as vector control and eradication of diseased citrus trees, to avoid the development of CLas-infected ACP generations with higher bacterial loads and, likely, a higher probability of spreading the pathogen in citrus orchards.

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.

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 Latency and Persistence of ‘Candidatus Liberibacter asiaticus’ in Its Psyllid Vector, Diaphorina citri (Hemiptera: Liviidae)

2017 ◽  
Vol 107 (3) ◽  
pp. 264-272 ◽  
Author(s):  
Maria Cristina Canale ◽  
Arthur Fernando Tomaseto ◽  
Marineia de Lara Haddad ◽  
Helvécio Della Coletta-Filho ◽  
João Roberto Spotti Lopes
Keyword(s):  
Latent Period ◽  
Acquisition Time ◽  
Diaphorina Citri ◽  
Candidatus Liberibacter Asiaticus ◽  
Old Adults ◽  
Sequential Inoculation ◽  
Candidatus Liberibacter ◽  
Citrus Huanglongbing ◽  
Liberibacter Asiaticus ◽  
Series Of Experiments

Although ‘Candidatus Liberibacter asiaticus’ (Las) is a major pathogen associated with citrus huanglongbing (HLB), some characteristics of transmission by the psyllid vector Diaphorina citri are not fully understood. We examined the latent period and persistence of transmission of Las by D. citri in a series of experiments at 25°C, in which third-instar psyllid nymphs and 1-week-old adults were confined on infected citrus for an acquisition access period (AAP), and submitted to sequential inoculation access periods (IAPs) on healthy citrus seedlings. The median latent period (LP50, i.e., acquisition time after which 50% of the individuals can inoculate) of 16.8 and 17.8 days for psyllids that acquired Las as nymphs and adults, respectively, was determined by transferring single individuals in 48-h IAPs. Inoculation events were intermittent and randomly distributed over the IAPs, but were more frequent after acquisition by nymphs. A minimum latent period of 7 to 10 days was observed by transferring groups of 10 psyllids in 48-h IAPs, after a 96-h AAP by nymphs. Psyllids transmitted for up to 5 weeks, when submitted to sequential 1-week IAPs after a 14-day AAP as nymphs. The long latent period and persistence of transmission are indirect evidences of circulative propagation of Las in D. citri.

scholarly journals Murraya paniculata and Swinglea glutinosa as Short-Term Transient Hosts of ‘Candidatus Liberibacter asiaticus’ and Implications for the Spread of Huanglongbing

2019 ◽  
Vol 109 (12) ◽  
pp. 2064-2073 ◽  
Author(s):  
Juan Camilo Cifuentes-Arenas ◽  
George Andrew Charles Beattie ◽  
Leandro Peña ◽  
Silvio Aparecido Lopes
Keyword(s):  
Sweet Orange ◽  
Diaphorina Citri ◽  
Candidatus Liberibacter Asiaticus ◽  
Principal Vector ◽  
Dead End ◽  
Valencia Orange ◽  
Murraya Paniculata ◽  
Citrus Rootstock ◽  
Candidatus Liberibacter ◽  
Liberibacter Asiaticus

Murraya paniculata and Swinglea glutinosa are aurantioid hosts of the Asian citrus psyllid (ACP) Diaphorina citri, the principal vector of ‘Candidatus Liberibacter asiaticus’ (Las). Las is the pathogen associated with huanglongbing (HLB), the Asian form of which is the most devastating disease of Citrus species and cultivars (Rutaceae: Aurantioideae). M. paniculata is a common ornamental and S. glutinosa is grown as an ornamental, a citrus rootstock, and a hedgerow fence plant. Because of the uncertain status of these plants as reservoirs of Las, a series of cross-inoculation bioassays were carried out in different environments, using infected Valencia sweet orange (Citrus × aurantium) infected shoot tops as a source of inoculum and D. citri nymphs and adults reared on M. paniculata and S. glutinosa to inoculate pathogen-free Valencia orange plantlets. In contrast to sweet orange, Las was more unevenly distributed and reached much lower titers in M. paniculata and S. glutinosa. Infections in M. paniculata and S. glutinosa were also transient. Very few insects that successfully acquired Las from M. paniculata and S. glutinosa were able to transmit the pathogen to healthy citrus. Transmission rates were low from M. paniculata (1.0%) and S. glutinosa (2.0%) and occurred only in a controlled environment highly favorable to Las and ACP using 10-day-old adults that completed their life cycle on Las-positive plants. Our study showed that in HLB-endemic areas, M. paniculata and S. glutinosa can be deemed as epidemiologically dead-end hosts for Las and are not important alternative hosts of the pathogen for transmission to citrus. However, under a combination of conditions highly favorable to Las infection and transmission and in the absence of effective quarantine procedures, these plants could eventually serve as carriers of Las to regions currently free from HLB.

scholarly journals Genome Sequence Resource of ‘Candidatus Liberibacter asiaticus’ strain 9PA From Brazil

Plant Disease ◽  
2021 ◽  
Vol 105 (1) ◽  
pp. 199-201
Author(s):  
P. A. Silva ◽  
J. Huang ◽  
N. A. Wulff ◽  
Z. Zheng ◽  
R. Krugner ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Sweet Orange ◽  
Whole Genome Sequence ◽  
Whole Genome ◽  
Candidatus Liberibacter Asiaticus ◽  
Citrus Production ◽  
Candidatus Liberibacter ◽  
Citrus Huanglongbing ◽  
Liberibacter Asiaticus ◽  
And Control

‘Candidatus Liberibacter asiaticus’, an unculturable α-proteobacterium, is associated with citrus huanglongbing (HLB), a devastating disease threatening citrus production in Brazil and worldwide. In this study, a draft whole-genome sequence of ‘Ca. L. asiaticus’ strain 9PA from a sweet orange (cultivar Pera) tree collected in São Paulo State, Brazil, is reported. The 9PA genome is 1,231,881 bp, including two prophages, with G+C content of 36.7%. This is the first report of a whole-genome sequence of ‘Ca. L. asiaticus’ from Brazil or South America. The 9PA genome sequence will enrich ‘Ca. L. asiaticus’ genome resources and facilitate HLB research and control in Brazil and the world.

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