Abstract
Rice is one of the most Al-tolerance species among small-grain cereals. Recent identification of a transcription factor ART1 revealed that this high Al tolerance in rice is achieved by multiple genes involved in detoxification of Al. ART1 is a C2H2-type zinc finger transcription factor and regulates the expression of 31 genes in the downstream. In this study, we attempted to identify a cis-acting element of ART1. We used the promoter region of STAR1, an Al tolerance gene in the downstream of ART1. With the help of gel shift assay, we were able to identify the cis-acting element as GGN[T/g/a/C]V[C/A/g]S[C/G]. This element was found in the promoter region of 28 genes among 31 ART-regulated genes. To confirm this cis-acting element in vivo, we transiently introduced this element one or five times tandemly repeated sequence with 35S minimal promoter and GFP reporter together with ART1 gene in the tobacco mesophyll protoplasts. The results showed that the expression of GFP reporter responded to Al. Furthermore, the expression increased with repetition of the cis-acting element. Our results indicate that the 5 residues identified are the target DNA binding sequence of ART1.
