Involvement of Fe nutrition in modulating oxidative stress and the expression of stress responsive proteins in leaves of Vigna radiata L.

摘要

Cadmium (Cd) is deleterious to all forms of life which in plants has competition with iron (Fe) for root uptake. This study investigated the protective role of iron (Fe) and its interaction with cadmium (Cd) in leaves of Vigna radiata L. (Green gram). To characterize the significance of Fe nutrition under Cd exposure, biochemical and gel based proteomic analysis was performed in the leaves of Vigna radiata exposed to Fe and Cd combined treatments: Fe-sufficient (+Fe/-Cd), and Fe-deficient (-Fe/-Cd) soils by comparing them with -Fe/+Cd treated plants and with non Cd exposed (+Fe/-Cd) plants. –Fe/-Cd led to an elevation in lipid peroxidation (TBARS) which was further increased in –Fe/+Cd plants. However, in +Fe/+Cd plants oxidative stress in terms of TBARS was minimized by 30%. Biochemical parameters such as total chlorophyll, total ascorbate and glutathione concentration reduced in –Fe/-Cd plants which was more reduced in -Fe/+Cd plants, whereas increased in +Fe/+Cd plants. Enzymatic activities such as APX, SOD, CAT, and GR activities were reduced in –Fe/-Cd plants which was more severe in –Fe/+Cd plants and in – Fe/+Cd enzyme assays were increased. Furthermore, proteomic analysis revealed 238 spots were reproducibly detected on 2D gels of all the four treatments among which 40 proteins were differentially expressed. Eight proteins of interest from differentially expressed proteins were identified and were classified as photosynthetic pigments, chloroplast precursor, stress responsive proteins, protein destination and secondary metabolism. These results indicate that Fe nutrition is involved in alleviating oxidative stress and expression of stress responsive proteins under Cd-stress.