Faculty of Natural and Agricultural Sciences
School of Biological Sciences
Department of Microbiology and Plant Pathology
Selected Highlights from Research Findings
Over the past five years, the Department of Microbiology and Plant Pathology has established a research group that focuses on the bacterial pathogens of plants. This includes pathogens of importance to both the agricultural and forestry sectors in South Africa. The pathogen that has received the most attention thus far is Pantoea ananatis. It is not only a pathogen that is found on a wide range of plants, but has also been implicated in opportunistic human infections. It is frequently isolated from different environmental sources, including the plant environment and from insects. It thus has an extraordinary ability to survive in a multitude of environmental niches, under a variety of conditions, and causes cross-kingdom infections. The research has primarily centred on developing reliable methods of identifying Pantoea species and attempting to understand their ability to infect the host and survive in its absence.
In order to distinguish between the Pantoea species, two approaches were developed, fluorescent amplified fragment length polymorphisms (f-AFLPs) and multilocus sequence analysis (MLSA). These techniques have allowed the researchers to move species incorrectly placed in the genus Pantoea and Pectobacterium to Tatumella and Pantoea respectively. They have also described one new Tatumella species, as well as 11 Pantoea species. The majority of these species are plant-associated, although clinical strains were also identified.
In 2006, Inqaba Biotech, using 454 technology, sequenced the genome of a virulent strain of P. ananatis isolated from Eucalyptus. This was the first plant pathogen to be sequenced in Africa. The genome has now been assembled and annotated, and compared to the genomes of closely related species. The pathogen shares various virulence and survival factors that are only associated with either plant pathogens, bacteria associated with insect hosts or human and animal pathogens. The genome sequence of P. ananatis thus gives an indication of an organism that is well adapted to survival in a wide range of environments and that is capable of causing disease symptoms in a number of hosts.
In the Potato Pathology Programme, Dr Jacquie van der Waals has been investigating the etiology, spread and virulence of Pectobacterium and Dickeya species on potatoes in South Africa. One of the most important findings is the first report of Pectobacterium carotovorum ssp. Brasiliensis, which causes blackleg of potatoes in South Africa This pathogen appears to be the most important causal agent of blackleg in the country. The disease poses a major potential threat to the South African potato industry, especially in terms of seed exports, tuber quality and
yield.
Contact person: Prof TA Coutinho.
Over the past five years, the Department of Microbiology and Plant Pathology has established a research group that focuses on the bacterial pathogens of plants. This includes pathogens of importance to both the agricultural and forestry sectors in South Africa. The pathogen that has received the most attention thus far is Pantoea ananatis. It is not only a pathogen that is found on a wide range of plants, but has also been implicated in opportunistic human infections. It is frequently isolated from different environmental sources, including the plant environment and from insects. It thus has an extraordinary ability to survive in a multitude of environmental niches, under a variety of conditions, and causes cross-kingdom infections. The research has primarily centred on developing reliable methods of identifying Pantoea species and attempting to understand their ability to infect the host and survive in its absence.
In order to distinguish between the Pantoea species, two approaches were developed, fluorescent amplified fragment length polymorphisms (f-AFLPs) and multilocus sequence analysis (MLSA). These techniques have allowed the researchers to move species incorrectly placed in the genus Pantoea and Pectobacterium to Tatumella and Pantoea respectively. They have also described one new Tatumella species, as well as 11 Pantoea species. The majority of these species are plant-associated, although clinical strains were also identified.
In 2006, Inqaba Biotech, using 454 technology, sequenced the genome of a virulent strain of P. ananatis isolated from Eucalyptus. This was the first plant pathogen to be sequenced in Africa. The genome has now been assembled and annotated, and compared to the genomes of closely related species. The pathogen shares various virulence and survival factors that are only associated with either plant pathogens, bacteria associated with insect hosts or human and animal pathogens. The genome sequence of P. ananatis thus gives an indication of an organism that is well adapted to survival in a wide range of environments and that is capable of causing disease symptoms in a number of hosts.
In the Potato Pathology Programme, Dr Jacquie van der Waals has been investigating the etiology, spread and virulence of Pectobacterium and Dickeya species on potatoes in South Africa. One of the most important findings is the first report of Pectobacterium carotovorum ssp. Brasiliensis, which causes blackleg of potatoes in South Africa This pathogen appears to be the most important causal agent of blackleg in the country. The disease poses a major potential threat to the South African potato industry, especially in terms of seed exports, tuber quality and
yield.
Contact person: Prof SN Venter.
Over the past five years, the Department of Microbiology and Plant Pathology has established a research group that focuses on the bacterial pathogens of plants. This includes pathogens of importance to both the agricultural and forestry sectors in South Africa. The pathogen that has received the most attention thus far is Pantoea ananatis. It is not only a pathogen that is found on a wide range of plants, but has also been implicated in opportunistic human infections. It is frequently isolated from different environmental sources, including the plant environment and from insects. It thus has an extraordinary ability to survive in a multitude of environmental niches, under a variety of conditions, and causes cross-kingdom infections. The research has primarily centred on developing reliable methods of identifying Pantoea species and attempting to understand their ability to infect the host and survive in its absence.
In order to distinguish between the Pantoea species, two approaches were developed, fluorescent amplified fragment length polymorphisms (f-AFLPs) and multilocus sequence analysis (MLSA). These techniques have allowed the researchers to move species incorrectly placed in the genus Pantoea and Pectobacterium to Tatumella and Pantoea respectively. They have also described one new Tatumella species, as well as 11 Pantoea species. The majority of these species are plant-associated, although clinical strains were also identified.
In 2006, Inqaba Biotech, using 454 technology, sequenced the genome of a virulent strain of P. ananatis isolated from Eucalyptus. This was the first plant pathogen to be sequenced in Africa. The genome has now been assembled and annotated, and compared to the genomes of closely related species. The pathogen shares various virulence and survival factors that are only associated with either plant pathogens, bacteria associated with insect hosts or human and animal pathogens. The genome sequence of P. ananatis thus gives an indication of an organism that is well adapted to survival in a wide range of environments and that is capable of causing disease symptoms in a number of hosts.
In the Potato Pathology Programme, Dr Jacquie van der Waals has been investigating the etiology, spread and virulence of Pectobacterium and Dickeya species on potatoes in South Africa. One of the most important findings is the first report of Pectobacterium carotovorum ssp. Brasiliensis, which causes blackleg of potatoes in South Africa This pathogen appears to be the most important causal agent of blackleg in the country. The disease poses a major potential threat to the South African potato industry, especially in terms of seed exports, tuber quality and
yield.
Contact person: Dr JE van der Waals (Smith).
The first report of pitch canker on mature pines in South Africa was from the Tokai plantations in the Western Cape. More recently, this devastating pathogen has been observed in the Eastern Cape. Until recently, the pathogen that causes this disease, Fusarium circinatum, has been restricted to pine seedling nurseries. The occurrence of F. circinatum on mature pine trees is of great concern. It has thus become more crucial for all forestry companies to prioritise the screening and selection of trees that are tolerant or resistant to infection by this pathogen. This will be the only sure means of avoiding dramatic losses in the longer term.
The importance of this disease has also necessitated more research into the pathogen F. circinatum. In a recent initiative, the genome of this pathogen has been sequenced and researchers in the departments of Microbiology, Plant Pathology and Genetics are actively characterising this genome.
Contact person: Dr ET Steenkamp.
This virology group in the Department of Microbiology and Plant Pathology has gained wide national and international recognition. Among others, the laboratory has a longstanding collaboration with the Centers for Disease Control and Prevention (CDC) in Atlanta, USA. One interesting example of this collaboration is found in field research in Kenya, primarily aimed at rabies and rabies-related virus discovery in bat species (collectively known as lyssaviruses). This research is crucial to the elucidation of the evolution and epidemiology of these important viruses in Africa and has led to several new isolations of known lyssaviruses, a filovirus isolate (Ebola family) and the identification of several other emerging viruses from bats in Kenya. Most recently, during 2009, Dr Wanda Markotter was a member of the field research team that discovered a novel lyssavirus in Kenya, designated Shimoni bat virus (SHIBV). The new virus, clearly to be considered a new species based on subsequent genetic characterisation, was the first virus to be isolated from a Commerson's leaf-nosed bat. This will be the first new lyssavirus species described from Africa since the isolation of Duvenhage virus in 1970. The demonstration of unique African lyssavirus cycles has far-reaching implications for research into vaccines, diagnostic procedures, viral evolution, epidemiology and host/viral ecology.
In 2009, Prof Louis Nel was a member of the World Health Organization Expert Advisory Panel on rabies and related zoonoses (Switzerland and France, 2009). He was a scientific advisor to the African Rabies Expert Bureau (Senegal 2009) and a scientific assessor of the European Union programme RABMEDCONTROL (Tunisia and Spain, 2009). Over the past three years, he has championed the cause of South Africa as a potential demonstration site for the elimination of rabies – with specific focus on KwaZulu-Natal, where dog rabies is endemic. The proposal was largely based on the extensive research data this UP laboratory and its collaborators have produced in recent years. In 2009, this proposal was chosen together with two other global proposals for rabies eradication and collectively awarded $10 million from the Bill and Melinda Gates Foundation.
Contact person: Prof LH Nel.
|
