A family of dispersed repetitive DNA sequences in tobacco contain clustersof W-box elements recognized by pathogen-induced WRKY DNA-binding proteins

Yang, PZ Chen, ZX

Pz. Yang et Zx. Chen, A family of dispersed repetitive DNA sequences in tobacco contain clustersof W-box elements recognized by pathogen-induced WRKY DNA-binding proteins, PLANT SCI, 161(4), 2001, pp. 655-664

42

INGLESE

Article

Plant Sciences","Animal & Plant Sciences

PLANT SCIENCE

0168-9452 → ACNP

161

4

2001

655 - 664

ISI

0168-9452(200109)161:4<655:AFODRD>2.0.ZU;2-H

We have previously identified in tobacco (Nicotiana tabacum) a group of pat hogen- and salicylic acid (SA)-induced DNA-binding proteins that contain th e highly conserved WRKY DNA-binding domain. In order to identify their pote ntial target genes, we have isolated tobacco genomic DNA sequences that con tain the consensus TTGAC(C/T) binding sites (W boxes) recognized by WRKY DN A-binding proteins. Surprisingly, sequence analysis of the 16 clones with t he strongest binding affinities for the WRKY proteins indicated that they a ll belong to a family of dispersed repetitive DNA sequences with an approxi mate copy number of 10,000 per haploid tobacco genome. These repetitive DNA sequences contain a number of direct and inverted repeats, a feature commo nly attributed to mobile genetic elements. BLAST search revealed that simil ar repetitive sequences are present in the promoters of the tobacco par/str 246C gene and the gene encoding a feedback-insensitive anthranilate synthas e alpha -2 chain. Interestingly, the par/str246C gene, which contains a W-b ox element in the repetitive sequence of its promoter, was induced dramatic ally in resistant tobacco plants after infection with tobacco mosaic virus. These results support that dispersed repetitive DNA sequences may serve as reservoirs for new functional cis-acting DNA elements that can be recruite d through chromosomal rearrangement to participate in transcriptional regul ation of nearby genes. (C) 2001 Elsevier Science Ireland Ltd. All rights re served.