Combined Effect of Cadmium and Lead on Durum Wheat

Abstract

Cadmium (Cd) and lead (Pb) are two toxic heavy metals (HMs) whose presence in soil is generally low. However, industrial and agricultural activities in recent years have significantly raised their levels, causing progressive accumulations in plant edible tissues, and stimulating research in this field. Studies on toxic metals are commonly focused on a single metal, but toxic metals occur simultaneously. The understanding of the mechanisms of interaction between HMs during uptake is important to design agronomic or genetic strategies to limit contamination of crops. To study the single and combined effect of Cd and Pb on durum wheat, a hydroponic experiment was established to examine the accumulation of the two HMs. Moreover, the molecular mechanisms activated in the roots were investigated paying attention to transcription factors (bHLH family), heavy metal transporters and genes involved in the biosynthesis of metal chelators (nicotianamine and mugineic acid). Cd and Pb are accumulated following different molecular strategies by durum wheat plants, even if the two metals interact with each other influencing their respective uptake and translocation. Finally, we demonstrated that some genes (bHLH 29, YSL2, ZIF1, ZIFL1, ZIFL2, NAS2 and NAAT) were induced in the durum wheat roots only in response to Cd.

Cadmium Uptake by Wheat (Triticum aestivum L.): An Overview

“…The nonenzymatic mechanisms of ROS detoxification may be activated; key nonenzymatic antioxidants comprise ascorbate, glutathione, flavonoids, vitamins, carotenoids, and alkaloids [52]. Aprile et al [54] suggested that wheat with low Cd and Pb in leaves has a high expression of the gene YSL2 which has a possible regulatory role in Cd compartmentalization in roots. The YSL2 is localized to vacuole membranes and can transport metal-NA complexes [55].…”

Ameliorative Effects of Exogenous Proline on Photosynthetic Attributes, Nutrients Uptake, and Oxidative Stresses under Cadmium in Pigeon Pea (Cajanus cajan L.)

“…Its destructive role in the photosynthetic apparatus has been highlighted, where it reduces pigment contents [21]. Cadmium decreases carbon assimilation, reshaping the chloroplast ultra-structure and thylakoid composition [22][23][24]. Its strong affinity toward sulfate and the portentous component of enzymes leads to enzyme inhibition [25].…”

Insight into the Role of Epigenetic Processes in Abiotic and Biotic Stress Response in Wheat and Barley

“…There is a crucial need to improve the production of wheat and barley for a growing population. However, environmental stresses such as salinity, drought, heat, freezing, heavy metal and even pathogen infections seriously threaten the growth and yield of wheat and barley under field conditions [5][6][7][8][9][10][11][12]. For instance, the majority of crops are highly sensitive to salinity, and the average yield of all important glycophytic crops decreased by 50%-80% at medium salinity conditions [5].…”

“…For heavy metal, cadmium (Cd) at low concentrations (0.3-0.8 mg kg −1 ) in soils could inhibit regular cell division, decrease photosynthesis and impair antioxidant enzyme activity [10,11]. In all major wheat-growing areas, lead (Pb) accumulation is generally accompanied by Cd pollution, seriously threatening crop yield and safety [12]. In acid soils, aluminum (Al) ions severely inhibit root growth and reduce the absorption of water and nutrients, resulting in crop yields [13].…”