Functional conservation of a root hair cell-specific cis-element in angiosperms with different root hair distribution patterns.
Vascular plants develop distinctive root hair distribution patterns in the root epidermis, depending on the taxon. The three patterns, random (Type 1), asymmetrical cell division (Type 2), and positionally cued (Type 3), are controlled by different upstream fate-determining factors that mediate expression of root hair cell-specific genes for hair morphogenesis. Here, we address whether these root hair genes possess a common transcriptional regulatory module (cis-element) determining cell-type specificity despite differences in the final root hair pattern. We identified Arabidopsis thaliana expansinA7 (At EXPA7) orthologous (and paralogous) genes from diverse angiosperm species with different hair distribution patterns. The promoters of these genes contain conserved root hair-specific cis-elements (RHEs) that were functionally verified in the Type-3 Arabidopsis root. The promoter of At EXPA7 (Type-3 pattern) also showed hair cell-specific expression in the Type 2 rice (Oryza sativa) root. Root hair-specific genes other than EXPAs also carry functionally homologous RHEs in their promoters. The RHE core consensus was established by a multiple alignment of functionally characterized RHEs from different species and by high-resolution analysis of At EXPA7 RHE1. Our results suggest that this regulatory module of root hair-specific genes has been conserved across angiosperms despite the divergence of upstream fate-determining machinery.
Kim
Dong Wook
DW
Department of Biology, Chungnam National University, Daejeon 305-764, Korea.
Lee
Sang Ho
SH
Choi
Sang-Bong
SB
Won
Su-Kyung
SK
Heo
Yoon-Kyung
YK
Cho
Misuk
M
Park
Youn-Il
YI
Cho
Hyung-Taeg
HT
D029681:Arabidopsis Proteins / Q000235:genetics; D001483:Base Sequence; D016384:Consensus Sequence / Q000235:genetics; D017124:Conserved Sequence / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D005964:Glucosyltransferases / Q000235:genetics; D019684:Magnoliopsida / Q000166:cytology / Q000235:genetics*; D008957:Models, Genetic; D008969:Molecular Sequence Data; D012275:Oryza / Q000166:cytology / Q000235:genetics; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000166:cytology* / Q000235:genetics*; D017354:Point Mutation / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics*; D017385:Sequence Homology
D029681:Arabidopsis Proteins; C427476:LRX1 protein, Arabidopsis; D010940:Plant Proteins; C095825:expansin protein, plant; C420969:CESA8 protein, Arabidopsis; D005964:Glucosyltransferases