Salt Stress Responses in Pigeon Pea (Cajanus cajan L.)

Abstract

Pigeon pea (Cajanus cajan L.) is a major food legume, widely popular as a split pulse in the tropical and sub-tropical parts of the world. India stands out to be the largest producer of pigeon pea accounting for over 90% of the global yield. Pigeon pea is a hardy legume with known tolerance against drought stress. Hence, it is often considered as `the food for the drought-affected regions'. However, the physiological effects of salt stress in this crop are less investigated. Genotype-dependent salt responses have been observed among pigeon pea cultivars which accumulate osmolytes like proline, glycine betaine and soluble sugars during salt stress. Photosynthetic efficiency is decreased due to degradation of essential pigments like chlorophyll and carotenoids. The chapter discusses on the ameliorative effects of mycorrhization and pre-sowing irradiation in pigeon pea exposed to salinity. Transgenic approaches have been adopted to generate tolerant lines of pigeon pea. In some instances, heterologous expression of a target gene from pigeon pea in other model plants also conferred multiple abiotic stress tolerance. The reports established these target genes as crucial regulators of both abscisic acid-dependent and abscisic acid--independent pathways across plant species.