title: Over-expression of HAP3b enhances primary root elongation in Arabidopsis.
abstract: HAPs, similar to Heme Activator Proteins (HAP) or nuclear factor-Y (NF-Y) in yeast and animals, play versatile roles in plant growth, development, and responses to environmental cues. HAP3b in Arabidopsis is a member in the HAP3 gene family and is involved in regulating flowering time through the long-day photoperiod pathway (Cai et al., 2007, Plant Physiol 145: 98-105). In this study, we report that overexpression of HAP3b enhances primary root elongation. Detailed analysis showed that HAP3b-overexpression did not affect the length of the root elongation zone and the cell length profiles in the elongation zone. Kinematic analysis indicated that root cells in HAP3b-overexpressors elongate faster than the cells in wild-type roots. Using GUS as a reporter gene, we showed that HAP3b is specifically expressed in the tip region of the root, where cell division and elongation occur. Our results provide evidence to support a role of HAP3b in regulation of root growth.
authors.affiliation: Department of Plants, Soils, and Climate, Utah State University, Logan, UT 84322, USA.
authors.forename: Jenny
authors.initials: J
authors.lastname: Ballif
authors.forename: Saori
authors.initials: S
authors.lastname: Endo
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Kotani
authors.forename: Jennifer
authors.initials: J
authors.lastname: MacAdam
authors.forename: Yajun
authors.initials: Y
authors.lastname: Wu
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D023081:CCAAT-Binding Factor / Q000235:genetics / Q000378:metabolism*; D049108:Cell Enlargement; D015870:Gene Expression; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D017930:Genes, Reporter; D018517:Plant Roots / Q000166:cytology / Q000254:growth & development*
chemical_list: D029681:Arabidopsis Proteins; D023081:CCAAT-Binding Factor; C525376:HAP3b protein, Arabidopsis