Chapter 2 - Breeding Oil Crops for Sustainable Production: Heavy Metal Tolerance

Abstract

Oilseed crops have been grown all over the world and are considered important crops due to their economical value. Heavy metal stress is one of the major abiotic stresses that limit oilseed crop growth and development. Heavy metals cause toxicity in oilseed crops via multiple mechanisms, as symptoms are highly crop, metal, and dose specific. Oilseed crops show potential to ameliorate metal-induced toxicity by adjusting their hemostasis to the optimum level. In oilseed crops, heavy metals endorse the production of free radicals, compete with the metal cofactors of plant enzymes, affect the activity of enzymes through the binding of sulfhydryl and nitrogen-containing groups, and cause cellular leakage through interactions with phospholipid head groups. Antioxidant defense system enhance the plant tolerance against metal-induced toxicity by upregulating the different antioxidant enzymes and nonenzymatic antioxidants that were involved in detoxification of free radicals in stressed plants. Phytochelatins also play significant roles in cell defense by binding and localizing metal ions in vacuoles to protect metal-sensitive metabolic centers in the cytoplasm. Genetic engineering techniques are used to enhance the ability of plants to withstand environmental stresses. Several transgenic approaches to growing oilseed crops are used to enhance metal uptake and plant growth. In this chapter, we have attempted to give an overview of the recent development on the response of oilseed crops to heavy metal stress, metal tolerance mechanisms, and the effect of metal toxicity on oil quality. Moreover, this chapter discusses breeding efforts regarding heavy metals in oilseed crops.