Role of the ZFHD1 and NAC transcription factors in drought-inducible expression of the early responsive to dehydration stress 1 (ERD1) gene of Arabidopsis

Abstract

The ZFHD and NAC recognition sequences (ZFHDRS & NACRS) play an important role in the dehydration-inducible expression of the ERD1 gene. Using yeast one-hybrid system, we isolated a cDNA encoding ZFHD1 transcriptional activator that binds to the 62-bp promoter region of ERD1, which contains the ZFHDRS. Both in vitro and in vivo analyses confirmed specific binding of the ZFHD1 to ZFHDRS, and base substitution analyses identified several critical nucleotides, which may serve as a core-binding site. Expression of ZFHD1 was induced by drought, high salinity and ABA. Microarray analysis of transgenic plants overexpressing ZFHD1 revealed that several stress-inducible genes were upregulated in the transgenic plants, and the plants showed significantly increased drought stress tolerance. Moreover, cooverexpression of the ZFHD1 and NAC genes, whose products were shown to be able to interact using yeast two-hybrid system, is required for expression of the ERD1 gene in transgenic Arabidopsis plants under unstressed condition.