Plants are indispensable to our life not only by providing food and oxygen but also by preserving the environment; by preventing outflow of water and soil, and by removing chemical pollutants from the air and soil. However, the ever-expanding activities of humans and the accompanying changes in both the regional and global environments have been threatening the lives of plants, especially vulnerable species. We are investigating the effects of various environmental factors, such as air pollutants, on plants and, by using modern biotechnology, are trying to improve or make good use of their abilities for environmental preservation. We are also engaged in environmental risk assessment of genetically modified plants.
1. DNA microarray for diagnosis of plants
Various detrimental factors in the environment damage plants, resulting in growth inhibition or withering. However, it is not easy to identify causal factors by visually inspecting the damaged plants. Furthermore, it is often necessary to detect stressed plants before the appearance of damage. Therefore, we are trying to develop a sensitive and reliable method for plant diagnosis, based on measuring changes in expression of a set of genes in a DNA microarray. With this method, we have been able to detect and discriminate between plants stressed by ozone, drought, or mechanical wounding.
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Genes with enhanced expression |
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Genes with unchanged expression |
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2. Generation of ozone-tolerant plants
Plants have an ability to purify polluted air; however, those planted or growing in or around big cities are often damaged by high concentrations of pollutants, especially ozone, resulting in damping off or attenuated vitality. Ethylene, a senescence-inducing plant growth regulator, is involved in the damage process. We identified the enzymes catalyzing ozone-induced ethylene production. By modifying the gene for one of these enzymes, we have succeeded in generating transgenic plants that exhibit enhanced tolerance to ozone.
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3. Development of a visual marker for identification of genetically modified plants
Various genetically modified plants, often called ﾒtransgenic plantsﾓ, have been generated and utilized for a variety of purposes, and their potential effects on our health and natural environment have been a matter of public concern. A satisfactory method to evaluate such effects needs to be established and it is important to monitor transgenic plants and their effects in the natural environment. A marker enabling us to easily discriminate transgenic plants from natural plants is needed for such a purpose. We are investigating the use of abnormal leaf morphology, caused by introduction of a homeobox gene, for such a marker of transgenic plants.
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