Expression profiling of cadmium response genes in ramie (Boehmeria nivea L.) root

Ramie (Boehmeria nivea), a perennial herb belongs to Urticaceae family, is a rapid growth and high biomass crop with highly tolerant and accumulative to heavy metals. However, the gene expression and regulation caused by cadmium (Cd) in ramie has not been well studied. In the present study, a gene expression database of ramie root in the absence (control) or presence of 100 μM Cd was established. Solexa high-throughput sequencing technology showed that 3,654,395 and 3,572,333 tags have been obtained from control and Cd treatment respectively. In total, 3887 genes were detected with significant differential expression levels, in which 2883 genes were up-regulated and 1004 genes were down-regulated. Gene ontology and pathway-based analyses were performed to determine and further to understand the biological functions of those differentially expressed genes. Fifteen genes were selected and their expression levels were confirmed by quantitative RT-PCR, and twelve of them showed consistent expression patterns with the digital gene expression data. Results on these expression profiling of genes lay the basis for biotechnological modification of new transgenic plants with improved phytoremediation capacity.