Determination and molecular analysis of nickel accumulation at Alyssum corsicum (Brassicaceae) grown in tissue culture conditions

A. corsicum is a candidate plant to be used in remediation and recovery of heavy metals especially nickel from the environment by a new technology phytoremediation. In this study A. corsicum plants were grown in tissue culture conditions supplied with 0.01 mM, 0.04 mM, 0.2 mM nickel concentrations. The nickel hyperaccumulation potential and the changes in plant?s metal content were detected by X-ray floresence spectrometer (XRF). The density of the metals Fe, Mg, Ca, Ni and morphological changes were detected at upper and lower stem leaves by scanning electron microscope energy dispersive X-ray anaysis (SEM-EDX). The shoots (932.5 µg/g) of the plant hyperaccumulated significantly more nickel than the roots (499.7 µg/g). The density of the trichomes was reduced with the increasing concentrations of nickel and some changes at the structure of the trichomes were observed. The changes are the curved trichome tips and the loss of the dynamic and denticulated structure. At 0.04 mM and 0.2 mM concentrations the centre of the trichomes had some different structures and denticulates. The analysis of antioxidant enzyme activities were performed at root and shoot samples. Catalase and glutathione reductase enzyme activity increased at 0.01 mM at both shoot and roots and decreased with the 0.2 mM nickel concentration. Ascorbate peroxidase activity increased at just 0.04 mM nickel concentration and showed variable values at other concentrations. The total leaf proteins of the plant were examined by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Two major bands were determined with 49 and 14 kDa molecular weight. Other minor bants dispersed between 45 and 18.4 kDa. The protein banding patterns of all plants grown at different concentrations of nickel were the same with each other in the aspect of density and mobility. In random amplified polymorphic DNA polymerase chain reaction experiments (RAPD-PCR) bands took place between 1000 bp and 300 bp. The bands showed no difference at the amplifications performed with OPW10, OPB10, OPA17 while they showed differences at some aspects with the primers OPO04, B7 primers. Differentially expressed genes (DEG) at 0.2 mM nickel treated plants were detected by special primers. One of the genes absent at 0.2 mM nickel treated plants is %93 similar with Arabidopsis thaliana 1. chromosome BAC T24P13 part genomic sequence. A differantially expressed gene appearing at 0.2 mM nickel treated plants is %99 similar with Arabidopsis thaliana Lhca2 protein (Lhca2) mRNA sequence and another less expressed gene at 0.2 mM nickel treated plant is %99 similar with Lobularia maritima chloroplast DNA completed sequence.