Industrial Microbiology: Microbial Biotechnology in Agriculture PDF

BIO 121: INDUSTRIAL MICROBIOLOGY MICROBIAL BIOTECHNOLOGY IN AGRICULTURE Genetically Modified Crops plants whose genome has been genetically engineered in order to favour the expression of desired physiological traits or the generation of desired biological products. Objectives ability to grow in har...

BIO 121: INDUSTRIAL MICROBIOLOGY MICROBIAL BIOTECHNOLOGY IN AGRICULTURE Genetically Modified Crops plants whose genome has been genetically engineered in order to favour the expression of desired physiological traits or the generation of desired biological products. Objectives ability to grow in harsh environments Herbicide tolerance Resistance to insect pests Control of pathogenic and parasitic microorganisms Resistance to viral diseases Induce nitrogen fixation Bt Crops genetically engineered plants containing the endospore or crystal toxins of the Bacillus thuringienses Bt Corn -more clean and marketable ears than conventional varieties -first Bt crop commercialized in the Philippines Bt Talong Bacillus thuringiensis - Gram positive soil bacterium -first approved biopesticide Active ingredients: Cry (crystal) proteins Cyt (cytolytic) proteins VIP proteins Mode of Action Plant Transformation Things to consider in plant transformation Promoters Successful expression of transgenes Constitutive (most cells) 35S promoter (CaMV 35S) Tissue dependent Inducible promoters Wound-induced promoters Marker genes To select successful transformants Antibiotic/herbicide resistance genes Metabolic genes Golden rice - fortified with vitamin A -just approved by Philippine regulatory agencies for commercial use. Why Golden Rice? Unequal micronutrients in plants Inadequate nutrients Micronutrient malnutrition Vitamin A - a carotenoid derivative essential for vision, immune response, epithelial cell growth, bone growth, regulation of adult genes. - accumulation in the rice grain cannot be achieved via breeding Added genes -ZmPSY1 - from maize -codes for phytoene synthase -to generate phytoene -crt1 - from Pantoea ananatis - phytoene desaturase -converts phytoene to lycopene -pmi -selective marker GMO Yes or No? Bio-fertizers microbial inoculants containing live or dormant cells of efficient strains which enhances plant nutrition via various processes. Mode of action Nutrient Cycling Secretion of growth promoting hormone, antibiotic, siderophore, low molecular weight metabolites, and production of lytic enzymes Competing with plant pathogens for nutrients Induction of systemic resistance in plants PGPM Plant-promoting microorganisms PGPR Plant-promoting rhizobacteria PGPF Plant-promoting fungi Advantages of using Biofertilizers 1. Improved nutrient uptake 2. Reduced in fertilizer usage 3. Improved crop yield 4. Improved quality of produce 5. Tolerance of biotic and abiotic stresses 6. Better acclimatization 7. Reclamation of degraded soils, habitat, etc. 8. Improve soil fertility 9. Reduced environmental pollution 10. Cost effective 11. Easy to handle and apply Bacterial biofertilizers Nitrogen Nitrogen Fixation - essential for growth and development - abundant in the atmosphere but not assimilable by plants -Reduced to ammonia via nitrogen fixation due to the presence of nitrogenase Nitrogen Fixers: cyanobacteria Azotobacter Rhizobium Phosphate Phosphate Solubilization - biosynthesis of macromolecules, energy transfer, signal transduction, photosynthesis, and respiration. -Solubilized by the secreted organic and inorganic acids (gluconic/ketogluconic acid) secreted by PSB. Bacillus megaterium Pseudomonas spp. Arthrobacter Potassium Potassium Solubilization -abundant in soil but only 1-2% are absorbed by plants -Dissolution of organic matter produces organic acid which dissolves K Bacillus mucilaginosus - helps in solubilization of rock K mineral powders such as mica, and orthoclase Fungal Bio-fertilizers Arbuscular mycorrhizal fungus (AMF) - fungus root -symbiotic association between plant roots and soil fungus Penicillium Apergillus Fusarium Trichoderma Advantages of using AMF 1. Increased phosphorus and micronutrient uptake 2. Increased water uptake 3. Increased resistance 4. Enhanced tolerance 5. Improved seedling survival 6. Enhanced beneficial microbial population in the root zone Biofertilizers work in synergy thus it can be applied as consortia eg. NPK bacterial fertilizers with AMF Biocontrol Applications Biocontrol Applications “Biological control of plant disease may be precisely defined as any condition or practice whereby survival or activity of a pathogen is reduced through the agency of any living organism with the result that there is reduction in incidence of the disease caused by the pathogen.” -Garret (1965) Biopesticides Bioinsecticides “for controlling disease causing fungi/bacteria and insects specifically targets insects Mode of Action Antibiosis Mycoparasitism Competition Induced Resistance Antibiosis involves a low-molecular weight compound or an antibiotic produced by a biocontrol agent (BCA) having a direct effect on the growth of plant pathogen Mycoparasitism involves tropical growth of biocontrol fungus mycelium towards the target pathogen followed by extensive coiling and secretion of various hydrolytic enzymes leading to dissolution of pathogen’s cell wall or membrane Competition indirect competition between pathogen and biocontrol agent Induced Resistance in Host Plants Advantages of using Biocontrol Agents 1. less harmful 2. often effective in small quantities. 3. multiply easily in soil and leave no residual problem 5. highly effective against specific diseases/pests 6. do not cause toxicity to plants and are eco-friendly and easy to handle. 7. reduce the use of conventional pesticides, while the crop yields remain high.