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Studies on the bacterium Candidatus Liberibacter spp., causal agent of citrus huanglongbing (ex-greening): diagnosis, biology and management

Grant number: 05/00718-2
Support type:Research Projects - Thematic Grants
Duration: February 01, 2006 - January 31, 2010
Field of knowledge:Agronomical Sciences - Agronomy - Plant Health
Principal researcher:Marcos Antonio Machado
Grantee:Marcos Antonio Machado
Home Institution: Instituto Agronômico (IAC). Agência Paulista de Tecnologia dos Agronegócios (APTA). Secretaria de Agricultura e Abastecimento (São Paulo - Estado). Campinas , SP, Brazil
Pesquisadores principais:
Helvecio Della Coletta Filho ; Sílvio Aparecido Lopes
Assoc. researchers:Alessandra Alves de Souza ; Dagmar Ruth Stach - Machado ; Diva Do Carmo Teixeira ; Edson Rodrigues Filho ; Eduardo Fermino Carlos ; Elaine Cristina Martins ; Elliot Watanabe Kitajima ; Gustavo Adolfo Astua Monge ; Juliana de Freitas Astúa ; Lilian Amorim ; Marco Aurélio Takita ; Maria Fátima das Graças Fernandes da Silva ; Maria Luísa Penteado Natividade Targon ; Mariângela Cristofani-Yaly ; Milton Groppo Júnior ; Nelson Arno Wulff ; Nelson Gimenes Fernandes ; Pedro Takao Yamamoto
Associated scholarship(s):08/09056-0 - Transmission and quantification of Candidatus Liberibacter americanus in periwinkle plants (Catharanthus roseus), BP.IC
08/01208-6 - Screening and evaluation of promoters and target genes aiming to citrus huanglongbing (greening) resistance, BP.PD
06/00768-2 - Bioinformatics for metagenome projects of the bacterium Candidatus Liberibacter, agent of huanglongbing (ex-greening) as well as transcriptome and shotgun of citrus leprosis mite (Brevipalpus phoenicis), BP.TT


The citrus industry is one of the most important activities of the agribusiness in Brazil, where the state of São Paulo is the main citrus producer and exporter of Frozen Concentrated Orange Juice (FCOJ). In Brazil, the low yield (around 2 boxes/tree/year) is highly associated to the incidence of pests and diseases (resulting in a substantial influence over the production costs), the production in non-irrigated areas, and the narrow genetic basis that has been used (i.e., only a few varieties grown in most of the orchards). In the past 20 years, many economically important diseases and pests have occurred in Brazil, which includes citrus variegated chlorosis (CVC), leprosis, black spot, alternaria brown spot, sudden death, citrus fruit borer, citrus leaf miner (CLM), scales, etc. Until recently, there has not been reported in the western hemisphere the occurrence of the huanglongbing (ex-greening), an extremely aggressive and damaging citrus disease wherever it occurs in the world. However, in 2004, the causal agent of the disease, the bacterium Candidatus Liberibacter spp., was for the first time found in the state of Sao Paulo in citrus plants that resembled its typical symptoms. Huanglongbing is one of the most destructive and severe diseases of citrus and causes damages in the plant development (chlorosis, leaf drop, and reduction of growth and roots) and fruit (misshapen, seed abortion, drop, and growth reduction). The causal agent is a phloem-limited bacterium, which has not been isolated so far, and is transmitted by the Asian citrus psyllid (Diaphorina citri), an insect easily found in Brazil. Under a multidisciplinary effort that has been made by putting together various research groups in the state of Sao Paulo, this proposal, as a thematic project, seeks to enhance the knowledge on the Huanglongbing pathossystem, which is still completely not understood under the conditions of the state of Sao Paulo. In spite of this, the objectives of this proposal involve to uncover partially the bacterium's genome, develop alternative systems for diagnostics, identify the bacterial diversity, find out how the bacterium multiplies in the citrus and other hosts tissues, study the effects of temperature over the severity and intensity of symptoms and bacterial multiplication as well as to evaluate the acquisition and persistence of the bacterium in the vector insect. Identification of these factors will provide the basis for orderly dissection of the processes underlying pathogenicity and, as a result, ways for the management of the disease and its vector. (AU)

Articles published in Pesquisa FAPESP Magazine about the research grant:
Let loose the wasps on the orange groves 
Avispas sueltas en los naranjales 
Fighting the yellow dragon 
Articles published in Agência FAPESP Newsletter about the research grant:
Articles published in other media outlets (0 total):
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Scientific publications (6)
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
COLETTA-FILHO, H. D.; CARLOS, E. F.; ALVES, K. C. S.; PEREIRA, M. A. R.; BOSCARIOL-CAMARGO, R. L.; DE SOUZA, A. A.; MACHADO, M. A.. In planta multiplication and graft transmission of `Candidatus Liberibacter asiaticus' revealed by Real-Time PCR. European Journal of Plant Pathology, v. 126, n. 1, p. 53-60, . (05/00718-2)
LOPES, S. A.; FRARE, G. F.; CAMARGO, L. E. A.; WULFF, N. A.; TEIXEIRA, D. C.; BASSANEZI, R. B.; BEATTIE, G. A. C.; AYRES, A. J.. Liberibacters associated with orange jasmine in Brazil: incidence in urban areas and relatedness to citrus liberibacters. PLANT PATHOLOGY, v. 59, n. 6, p. 1044-1053, . (05/00718-2, 07/55013-9)
BASSANEZI, RENATO B.; MONTESINO, LUIZ H.; GIMENES-FERNANDES, NELSON; YAMAMOTO, PEDRO T.; GOTTWALD, TIM R.; AMORIM, LILIAN; BERGAMIN FILHO, ARMANDO. Efficacy of Area-Wide Inoculum Reduction and Vector Control on Temporal Progress of Huanglongbing in Young Sweet Orange Plantings. PLANT DISEASE, v. 97, n. 6, p. 789-796, . (05/00718-2, 07/55013-9)
BASSANEZI, RENATO B.; PRIMIANO, V, ISABELA; MOREIRA, ALECIO S.. Inoculum reduction and vector control on the temporal progress of citrus variegated chlorosis incidence. Pest Management Science, v. 77, n. 7, p. 3333-3340, . (05/00718-2, 07/55013-9)
BASSANEZI, R. B.; BELASQUE, JR., J.; MONTESINO, L. H.. Frequency of symptomatic trees removal in small citrus blocks on citrus huanglongbing epidemics. CROP PROTECTION, v. 52, p. 72-77, . (05/00718-2, 07/55013-9)
GASPAROTO, M. C. G.; COLETTA-FILHO, H. D.; BASSANEZI, R. B.; LOPES, S. A.; LOURENCO, S. A.; AMORIM, L.. Influence of temperature on infection and establishment of `Candidatus Liberibacter americanus' and `Candidatus Liberibacter asiaticus' in citrus plants. PLANT PATHOLOGY, v. 61, n. 4, p. 658-664, . (05/00718-2)

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