This 10-page paper discusses about plant defense mechanisms. It consists of an abstract, introduction, mechanisms of defense against insects and pathogens, disease resistance genes, biotechnologies, case studies and future research and practical applications.
Review of Plant Defense Mechanisms
An imperiled plant is somewhat like a person. It has to depend on the defense mechanisms, both structural and metabolic to prevent harmful effects of the pathogens. It includes preexisting defense structures surface waxes, structure of epidermal cell walls, position of stomata and lenticles, thick cell walls, leaf hairs, defense structures formed in response to infection by the pathogen, histological defense structures, metabolic (biochemical) defense preexisting biochemical defense, metabolic defense induced by the attacking pathogen, defense through the hypersensitive reaction, defense through increased levels of phenolic compounds, "common" phenolics etc. Plants also activate a specific set of defense genes in response to assault. Recent technologies have enabled us to have plants with “useful genes” only, thus providing better crops in larger number. Unlike traditional plant breeding, which involves the crossing of hu
Many of these beneficial traits in new plant varieties fight plant pests -- insects, disease and weeds -- that can be devastating to crops. ndreds or thousands of genes, plant biotechnology allows for the transfer of only one or a few desirable genes. The implications are far-reaching: Not only are more land and labor used by agriculture, but more water is also needed --so much more that in regions where water is scarce, it may be worthwhile to address plant disease as a way to conserve on water usage. Mechanisms of genetic exchange and adaptive evolution are intertwined to provide plants with a supply of newly divergent R-gene alleles, with new pathogen specificities. But in addition, some plants have acquired morphological adaptations that make them at least partially resistant to insect predation. Many factors are associated with the ability of an insect to overcome plant resistance. First, however, the plant must know what it is up against. Plant Defense MechanismsStructural DefenseAll plants must assume forms that allow certain metabolic functions to take place, including photosynthesis, and orderly growth. A combination of molecular, biochemical, and physiological experiments are now being used to study the effect of these mutations on the wound signaling process. Resistance is not intended to always provide the sole means of control but is used as a direct control tactic that, in combination with others, provides desired protection of the crop from the insect pest. There seems an ample enough supply of the former, promising applications, to justify delaying the commercialization of the risky ones. Defense through Detoxification of Pathogen Toxins Some ( fusaric acid and Pyricularin) non-specific toxins have been shown to be detoxified by plants. In the broadest sense, plant resistance is defined as "the consequence of heritable plant qualities that result in a plant being relatively less damaged than a plant without the qualities. Included among these are oligosaccharide fragments derived from the plant cell wall, and the recently discovered polypeptide signal known as systemin. Scientists and regulators must be challenged to develop ways to distinguish almost assuredly safe and beneficial applications of transgenic technologies from those that raise significant risk concerns or offer dubious, at best short-lived benefits.