Resistance in Plants, Concepts and Mechanisms
Abstract
In contrast to most animals, plants are sessile organisms that they have not a circulatory system. So they have an innate immune system in each cell. In fact interaction between plants and their pathogens is based on systemic signaling capability from infection sites. In plant pathogen interaction sometimes pathogens produce elicitor and sometimes produce effector. On this basis, resistance in plants is divided to host and non host. On the other hand the plant responses depend not only on the recognition mechanisms but also very much on the biology of the interactions and genetic characteristics of plants and their pathogens. Gene – for – gene and the matching allel are two basic models for explanting of genetic basis of interaction between plants and their pathogens.
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Introduction
Have you ever thought that which of the two are more dangerous for humankind? Plant diseases or human diseases? Have you ever thought that all of kind of organisms from very small living things which have not even complete structural cell to human who is masterpiece of creation use green plants? So plants or green plants have a lot of consumers. If plants cannot defense against this widespread range of consumers the human health is threatened. The role of plants not only in our foods but also in our dressing and or in bioproduct production either under field conditions or in storage is so clear that it dose not require additional explanation. So plants as benefactors of world must be able to combat with their risk factors and use from defense mechanisms that are principally based on avoidance, resistance or tolerance [11].
Avoidance is mainly active against animal parasites and includes such diverse mechanisms as volatile repellents, mimicry and morphological features like hairs, thorns and resin ducts. Resistance is usually of a chemical nature. Little is known of tolerance; it is very difficult to measure and is usually confounded with quantitative forms of resistance [27]. Resistance in plants can include two basic form, quantitative and qualitative [3]. Also the other forms that all of them are based on the genetic characteristics of plants and their pathogen agents especially the interactions of these two factors. On the other hand the study of these genetic traits is very important because genetic improvement of plants is the best way to manage of damage caused by plant diseases.
Conclusion
In nature organisms are divided to producers and consumers. Green plant are the most important of producers so that without them life in planet earth is impossible. All of our efforts for understanding of mechanisms of interaction between plants and their pathogens are for production of more food and better food. For this purpose we need to more and better understanding of mechanisms that interfer in plant resistance. These studies are indifferent levels. At this time the study of basis genetic of resistance (of plants against pathogen) is very important. With the possibility of isolating specific genes that they have desirable characteristics it becomes possible to make genetic constructs by combining genes from different origins or even by changing the isolated genes. The possibilities are almost infinite and each construct has to be tested.
