Identification of Cd-Responsive Genes of Solanum nigrum Seedlings Through Differential Display

Abstract

Solanum nigrum is known as a Cd-hyperaccumulator: Its ability to accumulate large amounts of cadmium in leaves affords its designation as an effective phytoremediator. To identify Cd-responsive genes in S. nigrum, a nonradioactive differential display reverse transcription polymerase chain reaction technique was applied to isolate of genes whose transcription was altered in seedlings under Cd stress. A total of 48 DD bands were identified; from these bands, fragments corresponding to seven cDNAs were cloned. Reverse Northern dot-blot analysis confirmed the different expression patterns of these genes under cadmium toxicity. The homology analysis revealed that five of these cDNAs had a clear identity to Solanum species, and putative functions were assigned, including calmodulin, ascorbate peroxidase, catalase, glutamylcysteine synthetase, and iron-regulated transporter. Finally, the involvement of these genes in heavy metal tolerance is discussed.