Psychrotrophic Bacteria: A Boonto Higher Altitude Agriculture

Abstract

Psychrophilic or cold-tolerant microorganisms have the capacity to grow at 0°C or below 0°C. The low temperatures causes stress in them and to overcome the stress induced in them by low temperatures they have numerous adaptive responses at both cellular and molecular levels. There are many modifications in cell membranes which ensure that solutes are transported smoothly even at low temperatures. Other mechanisms include the synthesis of antifreeze proteins (AFPs), cold-shock proteins (Csps), cold acclimation proteins (Caps), cryoprotectants, ice nucleation factors and cold-adapted enzymes. Since agricultural ecosystems are mainly characterized by low temperatures because of the effects of global warming, the psychrophilic microbes have gained lot of importance to plants growing in cold climatic conditions and higher altitudes having temperatures below 0°C. Hence there is a need to identify the cold tolerant microbes that can sustain such lower temperatures, retain their functional traits under low temperature conditions. Such microorganisms can be used as inoculants in agricultural production systems in the temperate regions of the world. This review deals with the adaptations of cold tolerance/resistance microorganisms and the mechanisms operating in them. How they are helpful in increasing soil fertility by nitrogen fixation at higher altitudes and their utility in improving soil quality and productivity of agricultural crops of colder regions. Also, how these microorganisms are helpful in producing industrially important cold enzymes is also included in this review.