Identification and characaterization of nickel tolerance genes in Beta maritima

Abstract

Nickel is an essential micronutrient for plant growth. However, an excess amount of nickel is toxic for plants and animals. The Beta maritima plant which is known crop as salt and manganese tolerant nature. In this study, we aimed to identify nickel detoxification metabolism genes of Beta maritima by screening plant.s overexpressed cDNA library in yeast cells. After initial screening, three transformants were isolated that were able to grow in the presence of toxic nickel concentration. After the sequence analyses, three genes were named as NIC3, NIC6 and NIC8. We tested the growth rates of the yeast cells those were overexpressing cDNAs in solid mediums and showed similar nickel detoxification patterns. Then intracellular nickel concentrations were measured to see whether mentioned cDNAs pump nickel out of the cell or not. We also analysed the gene expression levels of NIC3 and NIC6 genes after appllying nickel stress to the plants to see the relations between nickel treatment and transcription changes of these two genes. Our data suggest that NIC3, NIC6 and NIC8 genes, besides their other functions, confer yeast cells nickel tolerance and may play roles in heavy metal detoxification for plant cells.