Open AccessRole of root UV-B sensing in Arabidopsis early seedling development
Author(s) -
Hongyun Tong,
Colin D. Leasure,
Xuewen Hou,
Gigi Yuen,
Winslow R. Briggs,
Zheng-Hui He
Publication year - 2008
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.0809942106
Subject(s) - arabidopsis , seedling , biology , root hair , mutant , arabidopsis thaliana , botany , morphogenesis , microbiology and biotechnology , biophysics , genetics , gene
All sun-exposed organisms are affected by UV-B [(UVB) 280–320 nm], an integral part of sunlight. UVB can cause stresses or act as a developmental signal depending on its fluence levels. In plants, the mechanism by which high-fluence-rate UVB causes damages and activates DNA-repair systems has been extensively studied. However, little is known about how nondamaging low-fluence-rate UVB is perceived to regulate plant morphogenesis and development. Here, we report the identification of anArabidopsis mutant,root UVB sensitive 1 (rus1 ), whose primary root is hypersensitive to very low-fluence-rate (VLF) UVB. Under standard growth-chamber fluorescent white light,rus1 displays stunted root growth and fails to form postembryonic leaves. Experiments with different monochromatic light sources showed thatrus1 phenotypes can be rescued if the seedlings are allowed to grow in light conditions with minimum UVB. We determined that roots, not other organs, perceive the UVB signal. Genetic and molecular analyses confirmed that the root light-sensitive phenotypes are independent of all other known plant photoreceptors. Threerus1 alleles have been identified and characterized. A map-based approach was used to identify theRUS1 locus.RUS1 encodes a protein that contains DUF647 (domain of unknown function 647), a domain highly conserved in eukaryotes. Our results demonstrate a root VLF UVB-sensing mechanism that is involved inArabidopsis early seedling morphogenesis and development.