Agricultural Microbiology Past Paper PDF 2024/2025

Important Glossaries In Agricultural Microbiology 2024/2025 1  Lec 1 Prepared by Group 1 1.Rhizosphere: -The root environment zone that stimulates the growth of microorganisms that use...

Important Glossaries In Agricultural Microbiology 2024/2025 1  Lec 1 Prepared by Group 1 1.Rhizosphere: -The root environment zone that stimulates the growth of microorganisms that use root-derived compounds as sources of C, N, Energy. -The zone of soil immediately adjacent to plant roots in which the kinds, number, or activities of microorganisms differ from that of the bluk soil. 2.Biofilm: Assemblages (accumulation) of microorganisms and their associated extracellular products at root-soil interface and typically attached to root or "rhizoplane" surface. 3.Endorhiza: Microorganisms colonizing inner cellular layers of plant root. 4.Spermosphere: Area of increased microbial activity around seed (imbibing, germinating) in soil 1 to 20 mm zone. 5.Decomposers: Organisms that break down organic matter, recycling nutrients back into the environment. 6.Ecosystem: It is referring to of the biotic and abiotic factors in an area. 7.Rhizoplane: surface of plant root with strongly adhering soil particles; provides microenvironment- soil-plant interface – for microbial activity. 8.Oligotrophs: An oligotroph is an organism that can live and grow in an environment that offers very low levels of nutrients. 9.Allochthonous: They are organisms who grow and transported to another habitat to be there transient member of community So, their presence is temporary. 10.Biogeochemical The process of recycling chemical elements either undergoing cycles: oxidation or reduction. 2  Lec 2 Prepared by Group 2 1.Rhizosphere: The zone of soil immediately adjacent to plant roots in which the kinds, number, or activities of microorganisms differ from that of the bulk soil. 2.Biofilm: Assemblages (accumulation) of microorganisms and their associated extracellular products at root-soil interface and typically attached to root or "rhizoplane" surface. 3.Endorhiza: microorganisms colonizing inner cellular layers of plant root. 4.Spermosphere: are of increased microbial activity around seed(imbibing, germinating) in soil 1 to 20 mm zone. 5.Decomposers: Organisms that break down organic matter, recycling nutrients back into the environment. 6.Ecosystem The ability of soil to bound back from a severe disturbance. stability : 7.Rhizoplane: surface of plant root with strongly adhering soil particles; provides microenvironment- soil-plant interface – for microbial activity. 8.Oligotrophs: An oligotroph is an organism that can live and grow in an environment that offers very low levels of nutrients. 9.Allochthonous: They are organisms who grow and are transported to another habitat to be their transient member of the community So, their presence is temporary. 3  10.Biogeochemical The process of recycling chemical elements either undergoing cycles: oxidation or reduction. Lec3 Prepared by Group 3 1.Microbial interactions in Soil microorganisms perform a number of interactions during soil : their presence in the soil , regularly improve the sustainable development of agroecosystem, plant growth and health. 2.Neutral interactions It is a neutral association between dissimilar microorganisms (neutralism): inhabiting the same environment without impacting each other (the two members neither losing or achieving anything from the relationship). 3.Mutualism: It is an obligatory or high specific interaction between two populations in which both of them benefit from each other. 4.Facultative mutualism: It occurs when one of the two partners can survive without it’s mutualistic partner by itself in some conditions. 5.Obligate mutualism: It occurs when both microorganisms live together very closely, and both species cannot survive without it’s mutualistic partner. 6.Lichen: The most common example for mutualism is the lichen, which is an association between fungus (ascomycetes) and algae (green algae) or cyanobacteria (blue green algae). 7.Commensalism: It is a relationship at which one population benefits, while the other population is unaffected (neither harmed nor benefited). 8. Protocooperation Synergism is a relationship that occurs between two or more (synergism) : populations at which both or all of them benefit. 10.Oligotrophic : Microorganisms can live in low nutrient values, which limits the lake’s ability to support animal life. 11.Eutrophics: Microorganisms live in excessive richness of nutrients (high nutrient values) in lake, frequently due to run off from the land. 4 12.Negative interactions: It consists of different relationships between different populations either two or more, at which one population at least is harmed while the other is either harmed, benefited, or not affected. 13.Ammensalism It is the most common negative relationship in nature at which (Antagonism) : one microbial population suppresses or adversely influences the growth or the activities of the other population in the same environment by producing inhibitory substances either directly or indirectly. 14.Parasitism : It is a relationship between two dissimilar organisms that is called host parasite relationship in which one of them (parasite) lives in or on the other organism (host). 15.Predation : Is the most dramatic relationship among microorganisms in nature, at which predator organism directly attacks a prey organism and feeds on it. 16.Competition : It is a relation that occurs between different populations in the soil which use the same limiting resources that are insufficient to support all the individuals. 17.Harmful relationship : While if the parasitism is accomplished on bacteria that are considered profitable to plants, it is considered as a harmful relationship for plant growth and health. 18.Useful relationship : If the parasitism is consummate on bacteria that are considered pathogenic to plants, it is considered as useful relationship for plant growth and health. 19.Symbiosis : It’s taken from the greek “sym” which means “with” and “biosis” that means “living” at which is defined as “living together”. 20.Resource competition : It occurs when the growth rates of both populations are limited by the same resource and one population has the ability to diminish the availability of that resource for the other populations. 21.Interference It occurs between two populations in which one of them competition : damages the other population’s habitat either physically or chemically and excludes it from the habitation. 5  Lec 4 Prepared by Group 4 1.Plant_ microbe The relationship between plants and microbes in the soil interaction : influenced by biotic and abiotic factor that affect plant health and microbial diversity. 2. Endophytes : Microorganisms that live inside plant tissues without causing harm often benefiting the host, including bacteria and fungi. 3.Epiphyte : Microbes that live on the surface of plants. They can be removed by washing/ultraviolet and radiation or chemicals. 4. R-S Ratio : The ratio of microbial population per unit weight of rhizosphere soil(R)/To the microbial populations per unit weight of the adjacent non-rhizosphere soil (s). 5.Mutualism : It is an obligatory or highly specific interaction between plant and microorganisms in which both of them benefit from each other. 6.Endomycorrhizae : It is a mutualistic association among mycorrhizal fungi and plant roots. 7. obligate mutualism : a form of mutualism where at least one organism cannot survive without the other such as in mycorrhizal associations. 8.Endomycorrhizae : It is a mutualistic association among mycorrhizal fungi and plant roots. 9.Appresssoria : Swellings formed by fungal hyphae at root epidermal cells aiding in root penetration. 10.Appressorium : A Specialized structure formed by fungi that allows them to adhere to and penetrate plant root cells facilitating nutrient exchange in mutualistic relationships. 11.Vesicles : Terminal hyphal swellings in certain mycorrhizal fungi that function as storage sites for nutrients and energy protecting nitrogenase from oxygen poisoning. 12.symbiotic nitrogen : The process where nitrogen fixing bacteria such as rhizobium convert atmospheric nitrogen into usable form. 6 13. Rhizobium spp : Nitrogen-fixing bacteria that form symbiotic relationships with leguminous plants. 14. Nodule : A tumor-like structure on plant roots, housing nitrogen- fixing bacteria in a symbiotic relationship. 15. Nod Factors : Signal molecules produced by Rhizobium, triggering root hair curling and nodule formation in legumes. 16. Flavonoids : Plant compounds that attract Rhizobium bacteria to root hairs, initiating symbiotic nodule formation. 17. Commensalism : It is a relationship at which one of them benefits, while the other is unaffected (neither harmed nor benefited ). 18. Protocooperation A relationship where both plants and microbes benefit, but it is (Synergism) : not obligatory. Each partner can live independently, unlike mutualism. This interaction often leads to the production of essential nutrients for plant growth, such as phytohormones and vitamins. 19. Ammensalism : A negative relationship where one microbe produces substances that harm the plant. 20. Parasitism : relationship between plant and microorganisms that is called host parasite relationship in which the microorganisms lives in or on the plant. 21. competition : It is a relation that occurs between plants and microorganisms in the soil which use the same limiting resources that are insufficient to support both of them. Lec 5 Prepared by Group 5 1.Biosphere : is the global ecological system integrating all living begins an I Their relationships including Their interaction with the elements of different spheres: Atmosphere, lithosphere, hydrosphere. 2.Carboncycle : one of the most Complex cycles on the earth and one of the biogeochemical cycles by which Carbon is exchanged between the living and non-living Things and back again in the lithosphere, hydrosphere, atmosphere of the earth. 7 3.Photosynthesis: The Process That responsible for the production of sugar from Solar energy, Corbon dioxide and water. 4.Respiration : The Process that responsible for metabolism of sugars to Produce Chemical energy for growth and reproduction. 5.Aerobic Require O growth, Final oxidation product is Co. Decomposition : 6.Anaerobic Can not grow in Presence of O₂, Final degradation Product is CH4 Decomposition: and Co2. 7.Mineralization : Is Conversion of organic substance to inorganic form. E.g. protein from OM will be converted to inorganic nitrogen in the soil. 8.Immoblization : Conversion of inorganic form into organic. E.g. inorganic nitrogen from the soil converted into microbial protein. 9.Diffusion : process by which molecules (Carbon dioxide Co₂) move from an area of high Concentration to an area of low Concentration. 10.Erosion : the process by which particles of Soil are washed into water. 11.Decomposition: Break down of dead plant and animal material and release of simpler organic and inorganic nutrients. 12. lithosphere the cycle that occur and effect on lithosphere. cycle : 13. Lactic Acid the cycle that occur and effect on lithosphere fermentation: 13-Lactic Acid fermentation: This occurs in some Anaerobic bacteria and fungi when there is no enough oxygen. 14.Sedimentation : Slow accumulation of material in one place. 15.Alcohol This occurs in some anaerobic bacteria and fungi, when Fermentation : there is no enough oxygen and, in this fermentation, Alcohol is produced as a final product in addition to Carbon dioxide. 8 16.Oxygenic A type of photosynthesis that produces oxygen as a Photosynthesis : byproduct, primarily performed by plants and cyanobacteria. 17.Anoxygenic Photosynthesis without oxygen production, Photosynthesis : typically using compounds like hydrogen sulfide instead of water. 18.Humus : The stable, organic component of soil resulting from the decomposition of plant and animal residues. 19. C:N ratio : Carbon to Nitrogen ratio (C: N) is a ratio of the mass of carbon to the mass of nitrogen in substance. 20.Cellulases : refer to a class of enzymes produced by fungi, bacteria. Lec 6 Prepared by Group 6 1.Nitrogen : The nitrogen cycle is describing the transformations of nitrogen and nitrogen-containing compounds in nature. 2.Nitrogen fixation : The process in which the N2 that presences in the atmosphere breaks (triple bond between the N atoms) and combines with other compounds. 3.Non-symbiotic nitrogen It is a process at which nitrogen-fixing bacteria live as a fixation : free-living bacteria in the soil and fix nitrogen within plant rhizosphere. 4.the symbiotic nitrogen It is a process at which nitrogen-fixing bacteria fix fixation : nitrogen inside plant tissue at which both of them live in mutualistic relationships. 5. Nitrification : is the biological process of enzymatic oxidation that oxidize ammonia with oxygen into nitrite followed by the oxidation of these nitrites into nitrates. 6. Denitrification : is the process of reducing nitrate and nitrite, (which are highly oxidized forms of nitrogen that available for consumption by many groups of organisms), into gaseous nitrogen. 7.Ammonification : The process of mineralization of organic nitrogenous compounds (proteins) which results in the production of ammonia (NH3 and /orNH4+). 9 8.Decomposition : is a biological breakdown and biochemical transformation of is a biological breakdown and biochemical transformation of complex organic molecules of dead material into smaller and simpler organic and inorganic molecules. 9.Mineralization : Conversion of organic substance to inorganic form. 10. Immobilization : Conversion of organic and /or/ inorganic nitrogen into organic nitrogen. (C/N > 30:1). 11.Nitrogen Assimilation Is the process of absorbing inorganic nitrogen (Immobilization) : compounds present in the environment like Nitrates and Ammonia (as the principal source of nitrogen for plants) and converting it into Organic Nitrogen compounds like amino acids. 12.Anaerobic Ammonium It is a process at which Bacteria combine ammonia and Oxidation (Anammox) : nitrite directly into dinitrogen gas. 13.Physiochemical process that convert N2 to N2O or NO3. Nitrogen fixation : 14.Biological The conversion of free nitrogen of atmosphere into Nitrogen fixation : the biologically acceptable form of nitrogenous compounds. 15.Non-symbiotic nitrogen free living bacteria are responsible for this process. Fixer : 10 11