Most sustainable and environmentally acceptable control may be achieved using biocontrol agents due to the effort to reduce the use of agrochemicals and their residues in the environment and in food (Haggag and Abdel-latif 2007). Identifying, understanding and utilizing microorganisms or microbial products to control of plant diseases and to enhance crop production are integral parts of sustainable agriculture. Biological control is a potent means of reducing the damage caused by plant pathogens (Haggag 2002; Jeyarajan and Nakkeeran 2000). Biological control of plant disease can occur through different mechanisms, which are generally classified as antibiosis, competition, suppression, direct parasitism, induced resistance, hypovirulence and predation (Johnson and Curl 1972; Chaurasia et al. 2005). The antagonistic activity has often been associated with production of secondary metabolites (Haggag and Abdel-latif 2007; Silva et al. 2001). Plant associated microorganisms fulfill important functions for plant growth and health. These rhizospheric microorganisms could be exploited for its innumerable properties and active metabolites (Tamilarasi et al. 2008). Biological control of plant disease is defined as “The involvement of the use of beneficial microorganisms, such as specialized fungi or yeast or bacteria to attack and control the plant pathogens (i.e., fungi, bacteria, nematodes or weeds) and the diseases they are causing (Fravel 2005). Biocontrol is a potent means of reducing the damage caused by plant pathogens (Jeyarajan and Nakkeeran 2000). The relationship of PGPR and biocontrol is not only important but also worthwhile. A biocontrol strain should be able to protect the host plant from pathogens and fulfill the requirement...
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...teria for a considerable length of time. The carrier must display two fundamental properties; it must support growth of the target organism and maintain desired population of inoculant strains over the acceptable time period. Carriers may be either organic or non organic. It should be economical and easily available and long shelf life. The carrier should be nearly sterile, chemically and physically uniform, display high water holding capacity, high water retention, suitable for as many bacterial species and strains as possible and supports growth and survival. It should be easily manufactured, amendable to nutrient supplement, nearly neutral pH or easily adjustable, manageable in the mixing, curing and packaging operations. Non toxic, biodegradable, non polluting, minimize environmental risks such as the dispersal of cells to the atmosphere or to the ground water.
A pathogen can be anything that causes a disease, including bacterium which causes meningitis, Viruses causing hepatitis A-C, and a fungus that cause athlete's foot. Plant pathology bacteria can serve economically damaging diseases, from spots, pustules on leaves and fruit, tuber rots to a plant's death. Some bacteria causes a hormone base distortion of leaves and shoots called fasciation. Fungi pathogens spread through plants to steal nutrients of living plants and carry out the part of the life cycle in soil. Mycorrhizae fungi make carbohydrates from plant roots, enhancing plant uptake of inorganic nutrients such as phosphorus and nitrogen. Cripps, C.L reported on mycorrhizae that “ The relationship is considered nonpathogenic, and of benefit to the plants involved.”- describing that the relationship between mycorrhizae and pathogens is nonpathogenic because mycorrhizae cancels out the disease. Over 85% of plants in nature have the mycorrhizae condition to keep pathogens away. This is why gardeners buy mycorrhizae fungi to help stop diseases of plants and for the safety of humans catching the disease through eating the plants. Food is one of the most important factors in the ecology life cycle and mycorrhizae makes it safe for these plants to take part in the
The basis for the symbiotic relationship in these species is complex. The infection of the host cell by rhizobia occurs within the plant’s root nodules. Bacteroides, gram-negative anaerobic bacteria, are isolated from the host cell by a peribacteroid membrane; the membrane between the plasma membrane of the cell and the membrane of the bacteroid. The bacteroid contains differentiated rhizobia, which are able to fix nitrogen due to the supply of carbon from the host plant. Sucrose is delivered to the nodules of the root via the phloem, where it is cleaved by suc synthase, and enters the Krebs cycle. The product of glyco...
The Advantages and Disadvantages of the Biological Control Method of Pest Management The biological control method of pest management does not use chemicals. Biological control uses various organisms that are either predators or parasites to the pest. A pest is an organism which causes damage to people and their crops, however this is an economical definition, as opposed to a biological one. Something is considered to be a pest when it reduces productivity by 5-10%. Plants require certain mineral ions in order to grow well, however there is a limited amount of these in soil.
Traits from various organisms lead to the DNA development to increase pest resistance within GMO crops. A study from UCSD (The University of California in San Diego) presents a report about how a toxic bacterium can both increase pest resistance and be safe for human consumption. This reduces the overall quantity of pesticide chemicals manipulated upon plants hence possibly diminishing pesticide exposure.
1999). Fungal pathogens that have been discovered in Arabidopsis plants, such as Rhizopus niveus, are made of several different types of lipases, including triacylglycerol lipases (Falk et al. 1999). Therefore, when an Arabidopsis plant encounters these fungal enzymes, the contained lipids are hydrolyzed by the EDS1 proteins and the fungal pathogen is
The biotechnology frontier, especially developments in the field of genetic, promises- and to some degree has already archived - a revolution in agriculture and human health care. But proving the means to develop plant species that are more disease-and-pest-resistant, more tolerant of drought, and able to grow during extended periods of adverse conditions.
Plants like many eukaryotic composed organisms have the ability to detect and protect themselves against microorganisms known as pathogens. Plant fossils have recorded that land plant’s existence was established 480 million years ago, but molecularly, plant evolution began 700 million years ago. Molecular interaction with microbes and other organisms gave the shape and structure of plants, giving us an idea that microbes also evolve according to its host. Plants lack mobility depriving themselves from a somatic secondary immune response like many mammals giving pathogens the ability to easily attack. Pathogenic microbes can access plants by penetrating through the leaves, entering through plant wounds, or by using the stomata a natural pore on plants that opens and closes for gas exchange. To detect and stop from extensive damage from microbes, plants developed an immune system through its structure, chemicals, and defense proteins.
Plants are grown under controlled and sterile conditions which reduce the risk of being exposed to pests, pathogens and diseases.
Weed Control Management in Crop Production. Eons ago, our ancestors were nomadic peoples that relied on their physical abilities as well as luck to survive. Our ancestors were people that obtained their food through hunting and gathering. With the intelligence inherent in the human race, our ancestors soon realized that the hunting and gathering lifestyle was not very reliable, nor did it allow much in the way of free time.
Chickpea (Cicer arietinum Linn.) is a deep rooted crop which belonging to the family Fabaceae. Chickpea is known to be the first domesticated grain legume crop of the Old World (Van der Maesen, 1972). India is the major producer of chickpea, contributing for approximately 65% of the annual world production and at the same time major importer of chickpea. The production of chickpea is limited by various biotic and abiotic stresses throughout the world. There are about 50 pathogens associated with chickpea (Nene, 1980), which include 35 fungi, 9 viruses and 2 bacteria and 4 nematodes. Among the most important biotic stresses that limit chickpea production worldwide, Ascochyta blight is considered to be the most notorious one that hampered the overall yield of the crop (Nene, 1982; Chongo et al., 2000).
Genetic engineering enhances plant resistance to drought, salinity, disease, pests and herbicides. The aim is to try and enhance the growth, productivity, nutrient value, and chemical composition of the plants. Chemicals are constantly being developed or improved to enhance the competitiveness and adaptability of crops, and to kill the parasites and weeds which plague the agricultural sector. . This however is not always good as the plant and the pests then become resistant to these new chemicals defeating the purpose of it being used. The new chemicals which are produced to kill these strong pests and weeds may be more harmful to other plants and remove nutrients within the soil in turn reducing the yield of agricultural crops. The benefits of these characteristics are seen in Argentina according to Pelletier (2010) as they use glyphosphate resistant soybean which allowed the comeback of this crop, as the so...
Zimmerman, H. G. and Neser, S. 1999. Trends and prospects for biological control of weeds
Biotechnology helps in protecting the environment,It provides crops with protection from viruses and insects by reducing the number of pesticid...
The bacterium in which the genetic material is derived from produces certain toxins that prove to be toxic for several common agricultural pests. These toxins responsible for the insecticidal properties of the bacteria are vegetative insecticidal proteins (Vip), crystal (Cry) and cytolytic (Cyt) toxins. The use of Cry genes, however, is more commonly used when altering the plants’ genetic material, primarily because i...
Studies have shown that there are bacteria and fungi with certain strains that live in soil. When they are applied to the seeds, they can aid crops by invigorating plant growth or by decreasing the damage created from plant pathogens bred from the soil. Another example is the bacterial species, Mycorrhiza. It is a fungus, which is able to form a union with a majority of land plants. When this action occurs, that symbiotic relationship assists to increase uptake by the root system to about 90 percent. This in turn helps the plant take in water and nutrients from deep inside the soil. It also allows the activation of genes and physiological changes in the plant which helps them to survive drought circumstances. Other microbes are also able to lift a plant 's resistance to bugs. A larger focus on microorganisms colonizing our plants and sharing a symbiotic relationship with them would greatly improve yields and lessen the need for costly fertilizers and pesticides. Information such as this would be very useful for students in college who are interested in businesses such as