USE OF GENETICALLY IMPROVED NITROGEN-FIXING CYANOBACTERIA IN RICE PADDY FIELDS - PROSPECTS AS A SOURCE MATERIAL FOR ENGINEERING HERBICIDE SENSITIVITY AND RESISTANCE IN PLANTS

Cyanobacteria are the largest and most widely distributed group of pho tosynthetic prokaryotes on Earth, forming a prominent component of mic robial populations in wetland soils, especially in rice paddy fields, and significantly contributing to fertility as a natural biofertilizer . Modern agricultural fields are generally treated with high doses of synthetic nitrogenous fertilizers and pesticides having adverse effect s on the soil microflora of naturally occurring N-2-fixing cyanobacter ia. This review deals with some of the advances made during the last f ew decades in the areas of developing ammonia derepressible pesticide- resistant cyanobacterial mutants for algalization of the wet agricultu ral fields as a viable and efficient N-photobiofertilizer.