Prof. Teresa Coutinho
Dept of Microbiology and Plant Pathology
Forestry and Agricultural Biotechnology Institute (FABI)
University of Pretoria
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Pantoea ananatis is the causal agent of bacterial blight and die-back of young eucalypts in South Africa.  This bacterium causes spots on the leaves which often coalesce to form larger lesions.  Shoot tip die-back may also occur.  The disease is particularly problematic in nurseries and mainly on E. grandis x E. nitens clones.

P. ananatis not only attacks this host but has also been found to cause a stalk disease of maize locally and cause a variety of other symptoms on onions, melons, pineapple, rice and sudan grass in other parts of the world.  It has also been reported to cause infections in humans.  Little is known about the ecology and biology of the diseases caused by P. ananatis.  In the case of eucalypts, we know it is a common epiphyte on leaves, and that high relative humidity and warm temperatures favour disease development. 

Genomics provides a wealth of information including all the proteins that the organism can produce.  This helps in the understanding of the ecology, biology and pathology of a pathogen.  Through funding obtained from the University of Pretoria and the NRF, the genome of a virulent strain of P. ananatis from eucalypts was sequenced in May 2007. The genome is 4.7 megabases in size (Fig. 1). 

The genome has been put through a computer system which has annotated known genes and it has been compared to the sequences of other genomes of bacteria belonging to the same family.  A number of pathogenicity factors have been identified and their function is currently being investigated.  We have discovered several unique elements in this genome which is going to provide a deeper understanding of how P. ananatis functions as both a pathogen of plants and humans.  This research is being undertaken in collaboration with the Scottish Crops Research Institute in the UK. 

Profs. Teresa Coutinho and Fanus Venter
Dept of Microbiology and Plant Pathology
Forestry and Agricultural Biotechnology Institute (FABI)
University of Pretoria
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