Proline improves copper tolerance in chickpea (Cicer arietinum)

Abstract

The present study suggests the involvement of proline in copper tolerance of four genotypes of Cicer arietinum (chickpea). Based on the data of tolerance index and lipid peroxidation, the order for copper tolerance was as follows: RSG 888 > CSG 144 > CSG 104 > RSG 44 in the selected genotypes. The basis of differential copper tolerance in chickpea genotypes was characterized by analyzing, antioxidant enzymes (superoxide dismutase, ascorbated peroxidase and catalase), phytochelatins, copper uptake, and proline accumulation. Chickpea genotypes showed stimulated superoxide dismutase activity at all tested concentrations of copper, but H(2)O(2) decomposing enzymes especially; ascorbate peroxidase did not increase with 25 and 50 microM copper treatments. Catalase activity, however, increased at lower copper concentrations but failed to stimulate at 50 microM copper. Such divergence in responses of these enzymes minimizes their importance in protecting chickpea against copper stress. The sensitive genotypes showed greater enhancement of phytochelatins than that of tolerant genotypes. Hence, the possibility of phytochelatins in improving copper tolerance in the test plant is also excluded. Interestingly, the order of proline accumulation in the chickpea genotypes (RSG 888 > CSG 144 > CSG 104 > RSG 44) was exactly similar to the order of copper tolerance. Based on hyperaccumulation of proline in tolerant genotype (RSG 44) and the reduction and improvement of lipid peroxidation and tolerance index, respectively, by proline pretreatment, we conclude that hyperaccumulation of proline improves the copper tolerance in chickpea.

Short-term physiological responses to copper stress in Salvinia auriculata Aubl.

“…The content of proline increased under exposure of Cu (up to 0.1 mM), indicating its role in the response to the metal as antioxidant agent (Singh et al, 2010). Moreover, the proline acted as an osmotic regulator, taking part in the stabilization of membranes (Shah and Dubey, 1998) and the formation of non-toxic complex (chelators) with this metal (Rauser, 1999).…”

Drought-induced changes in chlorophyll fluorescence, photosynthetic pigments, and thylakoid membrane proteins of Vigna radiata

“…(Singh et al 2010;Tripathi et al 2013). Proline influences protein solvation and preserves the quaternary structure of complex proteins, maintains membrane integrity under dehydration stress, and reduces photoinhibition (Demiral & Türkan 2004).…”

Isolation and characterization of a Δ1-pyrroline-5-carboxylate synthetase (NtP5CS) from Nitraria tangutorum Bobr. and functional comparison with its Arabidopsis homologue

“…The causative links between Pro accumulation, P5CS overexpression and tolerance to abiotic stresses are well documented. Free Pro accumulates in response to stresses such as high salinity [7], water deficit [8], extreme temperature [9], heavy metal toxicity [10,11] and nutrient deficiency [12]. Increased Pro levels and enhanced tolerance to diverse stresses have been observed in transgenic plants overexpressing P5CS genes, including rice [13,14], wheat [15], potato [16], tobacco [17], citrus [18] and chickpea [19,20].…”