Abstract
In the present study, the pathogenicity of 36 isolates of Guignardia species isolated from asymptomatic ‘Tahiti’ acid lime fruit peels and leaves, ‘Pêra-Rio’ sweet orange leaves and fruit peel lesions, and a banana leaf were characterized. For pathogenicity testing, discs of citrus leaves colonized by Phyllosticta citricarpa under controlled laboratory conditions were kept in contact with the peels of fruit that were in susceptible states. In addition, pathogenicity was related to morphological characteristics of colonies on oatmeal (OA) and potato dextrose agar (PDA). This allowed the morphological differentiation between G. citricarpa and G. mangiferae. Polymerase chain reactions (PCRs) were also used to identify non-pathogenic isolates based on primers specific to G. citricarpa. A total of 14 pathogenic isolates were detected during pathogenicity tests. Five of these were obtained from leaf and fruit tissues of the ‘Tahiti’, which until this time had been considered resistant to the pathogen. Given that the G. citricarpa obtained from this host was pathogenic, it would be more appropriate to use the term insensitive rather than resistant to categorize G. citricarpa. A non-pathogenic isolate was obtained from lesions characteristic of citrus black spot (CBS), indicating that isolation of Guignardia spp. under these conditions does not necessarily imply isolation of pathogenic strains. This also applied to Guignardia spp. isolates from asymptomatic citrus tissues. Using fluorescent amplified fragment length polymorphism (fAFLP) markers, typically pathogenic isolates were shown to be more closely related to one another than to the non-pathogenic forms, indicating that the non-pathogenic isolates display higher levels of genetic diversity.
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References
Agrios, G. N. (1995). Plant Pathology (3rd ed., pp. 3–41). San Diego: Academic.
Baayen, R. P., Bonants, P. J. M., Verkley, G., Carroll, G. C., Van Der Aa, H. A., De Weerdt, M., et al. (2002). Nonpathogenic isolates of citrus black spot fungus, Guignardia citricarpa identified as a cosmopolitan endophyte of woody plants, G. mangiferae (Phyllosticta capitalensis). Phytopathology, 92, 464–477.
Bonants, P. J. M., Carroll, G. C., De Weerdt, M., Van Brouwershaven, I. R., & Baayen, R. P. (2003). Development and validation of a fast PCR-based detection method for pathogenic isolates of citrus black spot fungus, Guignardia citricarpa. European Journal of Plant Pathology, 109, 503–513.
Blanco, C. G. (1999). Guignardia citricarpa Kiely: Análise genética cariotípica e interação com o hospedeiro. Ph.D. thesis. Piracicaba: Universidade de São Paulo.
Camargo, L. E. A. (1995). Análise genética da resistência e da patogenicidade. In A. Bergamin Filho, H. Kimati, & L. Amorim (Eds.) Manual de Fitopatologia-princípios e conceitos (vol. 1, pp. 470–492).São Paulo: Ceres.
European and Mediterranean Plant Protection Organization (2003). Diagnostic protocols for regulated pests. Guignardia citricarpa Bulletin, 23, 271–280.
Felsenstein, J. (1985). Confidence limits on phylogenies: An approach using the bootstrap. Evolution, 39, 783–790.
Glienke, C. (1995). Variabilidade genética no fungo endofítico Guignardia citricarpa Kiely detectada por RAPD.(MsC dissertation. Curitiba: Universidade Federal do Paraná.
Kotzé, J. M. (1981). Epidemiology and control of citrus black spot in South Africa. Plant Disease, 65, 945–950.
Kotzé, J. M. (1988). Black spot. In L. W. Timmer, S. M. Garnsey, & J. H. Grahan (Eds.). Compedium of citrus diseases (2nd ed., pp. 10–12). St. Paul: Academic Press Society.
Kumar, S., Tamura, K., Jakobsen, I. B., & Nei, M. (2005). Mega 2: Molecular evolutionary genetics analysis software. Tempe: Arizona State University. Retrieved April 14, 2005 from http://www.megasoftware.net/.
Lemir, A. H. M., Stadnik, M. J., Buchenauer, H., & Canton, N. V. (2000). In vitro production of ascospores and pathogenicity of Guignardia citricarpa, causal agent of citrus black spot. Summa Phytopathologica, 26, 374–376.
McOnie, K. C. (1964). The latent occurrence in citrus and other hosts of a Guignardia easily confused with G. citricarpa, the citrus black spot pathogen. Phytopathology, 54, 40–43.
Saitou, N., & Nei, M. (1987). The neighbor-joining method: A new method for reconstructing phylogenetic trees. Molecular Biology and Evolution, 4, 406–425.
Sambrook, J., Maniatis, T., & Fritsh, E. F. (1989). Molecular cloning: A laboratory manual (2nd ed). New York: Cold Spring Harbor Laboratory.
Shillito, R. D., & Saul, M. W. (1988). Protoplast isolation and transformation. Plant molecular biology: A practical approach (pp. 161–186). Oxford: IRL Press.
Whiteside, J. O. (1973). The possibilities of using ground sprays to control citrus greasy spot. Proceedings Florida State Horticultural Society, 8619–8623.
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Baldassari, R.B., Wickert, E. & de Goes, A. Pathogenicity, colony morphology and diversity of isolates of Guignardia citricarpa and G. mangiferae isolated from Citrus spp.. Eur J Plant Pathol 120, 103–110 (2008). https://doi.org/10.1007/s10658-007-9182-0
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DOI: https://doi.org/10.1007/s10658-007-9182-0