Prof. Teresa Coutinho

Forestry and Agricultural Research Institute

University of Pretoria
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There are a number of bacterial diseases of plants causing severe losses to agricultural, ornamental and forest tree species in South Africa.  Despite this there are few trained phytobacteriologists conducting research in this important area of plant pathology.  The number of postgraduate students preparing theses on bacterial diseases is also declining.  Between 1970 and 2005, 8 PhD and 39 MSc degrees were awarded to students whose research was conducted in this field.  Only six of these students obtained their degrees in the past five years.  For the same period, 1970 to 2005, 142 articles were published in accredited journals with only 10 published in the last five years. 

In the light of the above and the appearance of two bacterial diseases of Eucalyptus, bacterial blight and die-back and bacterial wilt, in South Africa Prof. Fanus Venter, a bacteriologist, and myself initiated a research project on phytobacteria.  This project falls within the Tree Protection Co-operative Programme (TPCP) in the Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria.  Our primary focus is on Pantoea spp. associated with blight on Eucalyptus.  Our first objective was to rapidly and reliably distinguish between the seven species in the genus.  After investigating various options, fluorescent Amplified Fragment Length Polymorphisms (F-AFLPs) proved to be a useful tool and a paper describing the technique was recently accepted for publication in Plant Pathology.  A PhD student, Carrie Brady, is continuing to undertake taxonomic studies on the Pantoea spp. and she is now developing a Multilocus Sequence Analysis (MLSA) scheme for distinguishing between the species.

In South Africa, bacteria blight and die-back of Eucalyptus is caused by P. ananatis.  This pathogen infects a number of different plants including, for example, pineapple, onion, rice and maize.  Teresa Goszczynska who is doing her PhD part-time is undertaking research on the problems we are experiencing in South Africa with onion seed and in maize with P. ananatis.  She is employed by the ARC-PPRI and is the curator of the South African Collection of Plant Associated and Phytopathogenic bacteria.  Understanding the mechanisms associated with the virulence of P. ananatis is being undertaken by a PhD student, Pieter de Maayer.

Typical symptoms of blight on Eucalyptus leaves caused by Pantoea ananatis

Three MSc students are part of our programme.  Lorinda Swart is identifying Pantoea spp. associated with Eucalyptus from various parts of the world.  She is using F-AFLPs as well as attempting to refine other DNA-based methods to distinguish between species.  Rebecca Makhado is looking for epiphytic and endophytic strains of Pantoea associated with resistant and susceptible Eucalyptus grandis-x E. nitens clones.  Ancel Botha is focusing on understanding the etiology of the disease caused by P. ananatis on Eucalyptus.

For the past three years, our project has been funded primary by funds received from members of the TPCP, THRIP, the NRF and a Bilateral Governmental Agreement grant.  The latter grant supports a collaborative project between our group and the Laboratory for Microbiology, University of Gent, Belgium.