Applied and Environmental Microbiology (2008) 74, 3690-3701

Rodrigo P.P. Almeida, Fernanda E. Nascimento, John Chau, Simone S. Prado, Chi-Wei Tsai, Sílvio A. Lopes and Joao R.S. Lopes (2008)
Genetic structure and biology of Xylella fastidiosa strains causing disease in citrus and coffee in Brazil
Applied and Environmental Microbiology 74 (12), 3690-3701
Abstract: Xylella fastidiosa is a vector-borne, plant-pathogenic bacterium that causes disease in citrus (citrus variegated chlorosis [CVC]) and coffee (coffee leaf scorch [CLS]) plants in Brazil. CVC and CLS occur sympatrically and share leafhopper vectors; thus, determining whether X. fastidiosa isolates can be dispersed from one crop to another and cause disease is of epidemiological importance. We sought to clarify the genetic and biological relationships between CVC- and CLS-causing X. fastidiosa isolates. We used cross-inoculation bioassays and microsatellite and multilocus sequence typing (MLST) approaches to determine the host range and genetic structure of 26 CVC and 20 CLS isolates collected from different regions in Brazil. Our results show that citrus and coffee X. fastidiosa isolates are biologically distinct. Cross-inoculation tests showed that isolates causing CVC and CLS in the field were able to colonize citrus and coffee plants, respectively, but not the other host, indicating biological isolation between the strains. The microsatellite analysis separated most X. fastidiosa populations tested on the basis of the host plant from which they were isolated. However, recombination among isolates was detected and a lack of congruency among phylogenetic trees was observed for the loci used in the MLST scheme. Altogether, our study indicates that CVC and CLS are caused by two biologically distinct strains of X. fastidiosa that have diverged but are genetically homogenized by frequent recombination.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Rodrigo P.P. Almeida, João Roberto Spotti Lopes

Research topic(s) for pests/diseases/weeds:
molecular biology - genes
general biology - morphology - evolution

---

Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Xylella fastidiosa	Citrus (genus)
	Xylella fastidiosa	Coffee (Coffea)