Manipulating programmed cell death pathways for enhancing salinity tolerance in crops

Abstract

One of the key challenges for researchers is to obtain a deeper under- standing of the strategies and mechanisms of plant adaptation to environmental stress that help overcome the limitations associated with climate change and loss of biodiversity. In this context, tolerance to salinity stress is one of the main abiotic factors constraining the plant growth, and production is of special importance. Programmed cell death (PCD) plays a protective role against biotic and abiotic stresses. PCD might play an important role in the maintenance of normal tissue homeostasis, regulation of cell metabolism, and remodeling of tissues after injury and infection as well as the elimination of damaged cells. Salinity stress induces an alteration in chloroplasts, mitochondria, cytoplasm, plasma membrane (PM), endo- plasmic reticulum (ER), Golgi apparatus, vesicle formation and trafficking, and vacuoles formation which may result in PCD in plants. The overexpression of pro- survival genes including anti-apoptotic genes and those involved in suppression of apoptosis genes in the transgenic plants to enhance abiotic stress tolerance has been the subject of a number of investigations, particularly in the context of salinity toler- ance. Therefore, the development of transformed plants for resistance to apoptosis could be an effective approach to improving salinity tolerance, while the use of complementary techniques like RNA-interfering (RNAi)-mediated gene knock- downs has been shown to be an interesting and appealing alternative. The objective of this review is to summarize the current state of knowledge on improving salinity tolerance in crop plants through manipulation of PCD pathways.