Red alert! How disease disables tomato plant's 'intruder alarm'December 05, 2008How a bacterium overcomes a tomato plant's defences and causes disease, by sneakily disabling the plant's intruder detection systems, is revealed in new research out today (4 December) in Current Biology. The new study focuses on a pathogen which causes bacterial speck disease in tomato plants. This bacterial invasion causes black lesions on leaves and fruit. Severe infection can cause extensive and costly damage to tomato crops, and researchers believe that understanding more about how this microbe works could lead to new ways of tackling it, and other plant diseases, without the need for pesticides. Scientists have found that the pathogen is very effective at attacking tomato plants because it deactivates and destroys receptors which normally alert the plant to the presence of a dangerous disease - in the same way that an intruder would deactivate the burglar alarm before gaining entry to a house. Professor John Mansfield from Imperial College London's Department of Life Sciences, one of the authors of the paper, says: "Once the receptors have been taken out, the plant's defences are 'offline' and the bacterium is able to spread rapidly, feeding on the plant without encountering any kind of resistance." Together with colleagues at the Max Planck Institute in Cologne and Zurich-Basel Plant Science Centre, Professor Mansfield used an experimental model plant called Arabidopsis, which is also affected by the disease, to examine what happens at the molecular level when bacterial speck infects a plant. The team found that the pathogen injects a protein into the host cell, which then deactivates and destroys, from the inside, receptors on the cell's surface which are designed to alert the plant to the presence of invading microbes. Deactivating the receptors stalls the plant's defence mechanism in its initial stages - ordinarily the cell surface receptors would kickstart a chain reaction leading to the production of antimicrobial compounds to fight and kill off the bacterial invader. Professor Mansfield says: "This area of research has a wider significance beyond black speck disease in tomato, because the microbes that cause plant diseases probably all employ similar attacking strategies to suppress resistance in their hosts. The more we understand about how the pathogens that cause disease overcome the innate immunity to infection in crop plants, the better our chances of developing approaches to disease control that do not require the use of potentially harmful pesticides" Imperial College London |
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| Related Bacterium Current Events and Bacterium News Articles Insect Resistance to Bt Crops can be Predicted, Monitored, and Managed Since 1996, crop plants genetically modified to produce bacterial proteins that are toxic to certain insects, yet safe for people, have been planted on more than 200 million hectares worldwide. Factors from common human bacteria may trigger multiple sclerosis Current research suggests that a common oral bacterium may exacerbate autoimmune disease. The related report by Nichols et al, "Unique Lipids from a Common Human Bacterium Represent a New Class of TLR2 Ligands Capable of Enhancing Autoimmunity," appears in the December 2009 issue of The American Journal of Pathology. Delft breakthrough in bioethanol production from agricultural waste With the introduction of a single bacterial gene into yeast, researchers from Delft University of Technology in the Netherlands achieved three improvements in bioethanol production from agricultural waste material: 'More ethanol, less acetate and elimination of the major by-product glycerol' This week the invention was published in the scientific journal Applied and Environmental Microbiology. Biologists discover bacterial defense mechanism against aggressive oxygen Bacteria possess an ingenious mechanism for preventing oxygen from harming the building blocks of the cell. On the Trail of a Vaccine for Lyme Disease: Yale Researchers Target Tick Saliva A protein found in the saliva of ticks helps protect mice from developing Lyme disease, Yale researchers have discovered. The findings, published in the November 19 issue of Cell Host & Microbe, may spur development of a new vaccine against infection from Lyme disease, which is spread through tick bites. Sweet as can be: how E. coli gets ahead Scientists at the University of York have discovered how certain bacteria such as Escherichia coli have evolved to capture rare sugars from their environment giving them an evolutionary advantage in naturally competitive environments like the human gut. Iowa State University researcher discovers key to vital DNA, protein interaction A researcher at Iowa State University has discovered how a group of proteins from plant pathogenic bacteria interact with DNA in the plant cell, opening up the possibility for what the scientist calls a "cascade of advances." New insight into predicting cholera epidemics in the Bengal Delta Cholera, an acute diarrheal disease caused by the bacterium Vibrio cholerae, has reemerged as a global killer. Outbreaks typically occur once a year in Africa and Latin America. But in Bangladesh the epidemics occur twice a year - in the spring and again in the fall. Iron controls patterns of nitrogen fixation in the Atlantic Scientists including researchers from the National Oceanography Centre, Southampton and the University of Essex have discovered that interactions between iron supply, transported through the atmosphere from deserts, and large-scale oceanic circulation control the availability of a crucial nutrient, nitrogen, in the Atlantic. There's a speed limit to the pace of evolution, Penn biologists say Researchers at the University of Pennsylvania have developed a theoretical model that informs the understanding of evolution and determines how quickly an organism will evolve using a catalogue of "evolutionary speed limits." More Bacterium Current Events and Bacterium News Articles |
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