The agriculturally important microorganisms come from bacteria, actinomycetes, blue green algae (BGA), fungi - including vesicular arbuscular mycorrhizae (VAM) - and viruses. They thrive in a variety of habitats including soil, living body systems and dead/decayed matter, marine, snow bound mountains and desert systems, water bodies, etc. Their genetic factors underlying the differential adaptability to such diverse habitats indicate an invaluable treasure of genes for the benefit of agriculture. The sectoral importance of microorganisms in agriculture has also increased with the integration of agriculture, intellectual property and services with the world trade agreement.
'The developing world is keenly looking forward to harness the genic power from microorganisms through the rapid development of their institutional capacity, through building of state-of-the-art laboratories, biosafety and other regulatory mechanisms, and human resource.
Most of the chemical reactions that take place in the soil, leading to increased availability of several major and micronutrients, often have active contribution of microbes. The nitrogen-fixing bacteria, blue green algae, and phosphate solubilising bacteria are already well known to enhance availability of major nutritional elements like N and P to plants whereas the decomposer bacteria are instrumental for recycling, and thereby increasing, the availability of carbon and several micronutrients from plant residues to soil.
Some other microorganisms similarly contribute towards improved plant health and higher crop yield through the production of growth stimulators such as plant hormones and vitamins, such biofertilising and phyto-stimulating genes from microbes obviously require intensive study for their application and use in agriculture. Research efforts have to be essentially focused on prospecting and mining of the microbial genic potential for use in crop and animal improvement. The developments in genomics and gene transfer through biotechnology, their relevance and role has further increased. The agriculturally important microbes are increasingly seen to be much more dynamic and focused gene resource for developing transgenics to increase productivity of agri-based products and quality, and incorporating resistance to biotic/abiotic stress factors in the plants and livestock.
Microorganisms in the rhizosphere are known to act in synergy with crops. The rhizosphere is generally defined as the soil region under the influence of the root. It includes the rhizoplane (surface of the root) and the endorhizosphere (intercellular space between the root tissues inhabited by non-symbiotic bacteria). The rhizodeposition, one of the main factors influencing the rhizosphere is the organic or inorganic production of the root within the soil. It corresponds to 15-40% of the total photosynthetic production of the plant and secretes an important carbon and energetic source towards the micro-organisms of the rhizosphere. It comprises sloughed of cells, secreted mucilage (facilitates water exchanges), soluble exudates (e.g. sugars, amino acids, attractants or antibiotics). The root also influences the rhizosphere by creating a negative oxygen gradient (root respiration), by absorbing water (increasing the soil air conductivity) and by absorbing mineral salts.
Indian Council of Agricultural Research (ICAR), country's apex organization engaged in agricultural research, has taken a step in this direction by starting a project on Application of Microorganisms in Agriculture and Allied Sectors (AMAAS).Thus, to fully exploit potential of microorganisms in agriculture and allied sectors, AMAAS Project has been started involving various research centers spread all over country i.e. State Agricultural Universities (SAUs) as well as ICAR institutions having expertise in different fields of microbiology.
The major objectives of the project are (a) deciphering structural and functional diversity of AIMs and to develop microbial map of the country; (b) improving nutrient use efficiency through microbial interventions for sustainable crop production; (c) development of microbe based technologies for agro-waste management and biodegradation for sustainable crop production; (d) development of microbe-mediated processes for product development and value addition in agriculture etc. The project is expected to help increase the agricultural production on sustainable basis. It will help to reduce the usage of chemical fertilizers, pesticides, herbicides, and insecticides. The project will help to generate technologies like post harvest technologies, agro-waste management technologies, bio control agents, diagnostic kits for identification of pathogens and novel genes for both biotic and abiotic stress. These technologies are the need of hour, which will help in reducing huge losses due to biotic and abiotic losses that account to 30 per cent at present.