Characterization of isolates that cause black rot of crucifers in East Africa

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Mulema, Joseph M. K. ; Vicente, Joana G. ; Pink, David ; Jackson, Alison C. ; Chacha, Duncan O. ; Wasilwa, L. A. (Lusike A.) ; Kinyua, Zakary M. ; Karanja, Daniel K. ; Holub, E. B. ; Hand, Paul (2012)

A study was conducted in the East African countries of Kenya, Tanzania and Uganda in the months of July and August 2009 with the objectives of assessing the status of black rot and race structure of Xanthomonas campestris pv. campestris in the three countries. Samples infected with black rot were collected from farmers’ fields mainly from Brassica oleracea crops (broccoli, cabbage, cauliflower and kales). A total of 399 farms were surveyed of which 260 were from Kenya, 91 from Tanzania and 48 from Uganda. Following successful isolations, a total of 249 isolates of the causal agent, Xanthomonas campestris pv. campestris were recovered. Pathogenicity of all isolates was confirmed on B. oleracea susceptible cultivars Copenhagen Market F1 and Wirosa F1. Sixty of the 250 isolates were race-typed using a differential set Brassica spp. Only two races, 1 (Kenya and Tanzania) and 4 (Kenya, Tanzania and Uganda) were observed however, another race (5) was observed from one isolate recovered from a B. rapa sample obtained from Tanzania in 2003. Genomic fingerprinting with repetitive-PCR revealed clusters that did not depict significant correlations between isolates and geographical location, isolates and host adaptation or isolates and race. However, it did demonstrate existence of genetic differences within the East African X. campestris pv. campestris population indicating that it is not a similar clonal population of the same genetic background.
  • References (6)

    Cook, A. A., Larson, R. H. & Walker, J. C. (1952). Studies on the disease cycle of black rot of crucifers. Phytopathology, 42, 162-167.

    Fargier, E. & Manceau, C. (2007). Pathogenicity assays restrict the species Xanthomonas campestris into three pathovars and reveal nine races within X. campestris pv. campestris. Plant Pathol., 56, 805-818.

    Flor, H. H. (1971). Current status of the gene-for-gene concept. Annu. Rev. Phytopathol., 9, 275-296.

    Flor, H. H. & Comstock, V. E. (1972). Identification of rust-conditioning genes in flax cultivars. Crop Sci., 12, 800-804.

    Hammer, Ø., Harper, D. A. T. & Ryan, P. D. (2001). PAST: Paleontological statistics software package for education and data analysis. Palaeontologia Electronica, 4, 9.

    Jensen, B. D., Massomo, S. M. S., Swai, I. S., Hockenhull, J. & Andersen, S. B. (2005). Field evaluation for resistance to black rot pathogen Xanthomonas campestris pv. campestris in cabbage (Brassica oleracea). Eur. J. Plant Pathol., 113, 297-308.

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