The impact of AMF symbiosis in alleviating drought tolerance in field crops

Recent climate changes are expected to cause more frequent and severe drought affecting major field crops. Most of the cultivated field crops have a symbiotic association with the arbuscular mycorrhizal fungi (AMF) which is present in rhizosphere of these crops. Members of these class of fungi includes species of Glomus, Gigaspora, etc. have been found to be colonizing roots and forming an association with field crops for mutual benefits of both the partners. This symbiosis is known to help the plant to tolerate drought with the positive effects on plant growth. This chapter provides an overview of possible biochemical and genetic mechanism involved in AMF assisted drought tolerance in field crops. The improved water and nutrient absorption with the help of extraradical hyphal growth of AMF is one the important factor in helping plants to avoid the ill effects of drought. Along with this, by increased concentration of many biomolecules like amino acids, polyamines, hormones ; osmotic adjustment with the help of total soluble sugar (TSS), proline, ascorbic acid, and removing reactive oxygen species through antioxidant enzymes and antioxidants; AMF helps plant to reduce the effects of drought. Besides this, the results of some studies have given new exciting genetic perspectives including cellular water transport by mycorrhized roots.