Global warming
has significant impact on conditions affecting plans, including temperature, carbon dioxide, precipitation and the interaction of these elements. Climate change induced by increasing emission of greenhouse gases such as carbon dioxide, methane, and nitrous oxide is likely to affect crops differently from region to region. The Intergovernmental Panel on Climate Change
(IPCC) reported that due to decreased water availability because of global worming, the poorest countries will be hardest hit with reduction in crop yields in most tropical and sub-tropical regions.
has significant impact on conditions affecting plans, including temperature, carbon dioxide, precipitation and the interaction of these elements. Climate change induced by increasing emission of greenhouse gases such as carbon dioxide, methane, and nitrous oxide is likely to affect crops differently from region to region. The Intergovernmental Panel on Climate Change (IPCC) reported that due to decreased water availability because of global worming, the poorest countries will be hardest hit with reduction in crop yields in most tropical and sub-tropical regions. High temperature affects the duration of crop growth cycles. It speeds up development. The shortening of such a cycle might have an adverse effect on growth and productivity as the biological age would occur sooner. High temperature stress disturbs cellular homeostasis and is responsible for severe retardation in growth and development of plant. Physiological, biochemical and molecular changes occur in plant metabolism during high temperature stress. These include protein denaturation, lipid liquefaction or perturbation of membrane integrity. Many of the changes that appear during acclimation to heat stress are reversible, but for prolonged stress period or for immense intensity of the stress, irreversible changes can occur and these can lead to death of crop plant.
Improvement of plant properties with enhanced tolerance to high temperature is one of the important ways to minimize this problem. Like high temperature, other abiotic stresses are also major obstacles to plant growth and productivity. Due to high temperature, drought, low temperature, high salinity and heavy metals in soil, every year billions of dollars are lost due to crop failure. The transcription control of stress-inducible genes is crucial in plant responses to abiotic stress. It has been identified that several kinds of transcription factors and signal transduction pathway component genes respond to environmental stresses in plants. Assembling of combination of these stress-inducible transcription factors and signal transduction pathway component genes in crop plants can reduce crop loss.
Combining of these genes is difficult by traditional plant breeding methods because there is limitation to cross plants artificially within the same species or with closely related species to bring different genes together. Transgenic technology enables plant scientists to bring useful genes together in one plant from a wide range of living sources, not just from within the species or closely related plants. The mechanism involved in this system is, identification and isolation of genes controlling specific characteristics in one kind of organism and moving copies of those genes into another different organism which will then also have those characteristics. This powerful tool enables us to combine useful genes which expand the possibilities beyond the limitations imposed by cross pollination and selection.
Bioassay is another useful method that helps quantitative estimation of the effects that result in a biological system after its exposure to a substance. This is done by comparing the activity of living organisms under standardized conditions versus the conditions under investigation. For quantitative measurement of the effects of high temperature, drought, cold, high salinity etc., bioassay method can be implicated on transgenic and non-transgenic plants.
Microarray analysis is a convenient technology for the global analysis of plant gene expression. It allows simultaneous measurement of the transcript abundance for hundreds of genes. It is a valuable tool for the characterization and identification of individual genes and gene families involved in controlling various biological processes ranging from development to response to environmental cues. In transgenic plants microarray technique identifies up-regulated and down-regulated genes. Through the analysis of these up-regulated and down-regulated genes we can assume the reasons for the phenotypic behaviour of transgenic plants to different abiotic stresses.
Searching high temperature stress inducible genes in plants--those can be a family of wild or weedy forms of a cultivated species--and transferring them in cultivated species is one of the most efficient strategy for improvement of crop species
in tolerance to high temperature. It has been proved that transgenic plants over-expressing high temperature stress-inducible genes are more thermo-tolerant than non-transgenic plants. The plant scientists have important role in overcoming stress problems using molecular techniques. To feed the increasing population of Bangladesh and to protect people against poverty and hunger, plant scientists should come forward with molecular research to protect crop against different abiotic stresses.
in tolerance to high temperature. It has been proved that transgenic plants over-expressing high temperature stress-inducible genes are more thermo-tolerant than non-transgenic plants. The plant scientists have important role in overcoming stress problems using molecular techniques. To feed the increasing population of Bangladesh and to protect people against poverty and hunger, plant scientists should come forward with molecular research to protect crop against different abiotic stresses.
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