title: Reduced expression of the SHORT-ROOT gene increases the rates of growth and development in hybrid poplar and Arabidopsis.
abstract: SHORT-ROOT (SHR) is a well characterized regulator of cell division and cell fate determination in the Arabidopsis primary root. However, much less is known about the functions of SHR in the aerial parts of the plant. In this work, we cloned SHR gene from Populus trichocarpa (PtSHR1) as an AtSHR ortholog and down-regulated its expression in hybrid poplar (Populus tremula×P. tremuloides Michx-clone T89) in order to determine its physiological functions in shoot development. Sharing a 90% similarity to AtSHR at amino acid level, PtSHR1 was able to complement the Arabidopsis shr mutant. Down regulation of PtSHR1 led to a strong enhancement of primary (height) and secondary (girth) growth rates in the transgenic poplars. A similar approach in Arabidopsis showed a comparable accelerated growth and development phenotype. Our results suggest that the response to SHR could be dose-dependent and that a partial down-regulation of SHR could lead to enhanced meristem activity and a coordinated acceleration of plant growth in woody species. Therefore, SHR functions in plant growth and development as a regulator of cell division and meristem activity not only in the roots but also in the shoots. Reducing SHR expression in transgenic poplar was shown to lead to significant increases in primary and secondary growth rates. Given the current interest in bioenergy crops, SHR has a broader role as a key regulator of whole plant growth and development and SHR suppression has considerable potential for accelerating biomass accumulation in a variety of species.
authors.affiliation: College of Agriculture and Bioengineering, Tianjin University, Tianjin, China.
authors.forename: Jiehua
authors.initials: J
authors.lastname: Wang
authors.forename: Sara
authors.initials: S
authors.lastname: Andersson-Gunnerås
authors.forename: Ioana
authors.initials: I
authors.lastname: Gaboreanu
authors.forename: Magnus
authors.initials: M
authors.lastname: Hertzberg
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Tucker
authors.forename: Bo
authors.initials: B
authors.lastname: Zheng
authors.forename: Joanna
authors.initials: J
authors.lastname: Leśniewska
authors.forename: Ewa J
authors.initials: EJ
authors.lastname: Mellerowicz
authors.forename: Thomas
authors.initials: T
authors.lastname: Laux
authors.forename: Göran
authors.initials: G
authors.lastname: Sandberg
authors.forename: Brian
authors.initials: B
authors.lastname: Jones
mesh_terms: D000704:Analysis of Variance; D017360:Arabidopsis / Q000033:anatomy & histology / Q000235:genetics* / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D015536:Down-Regulation / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics*; D005816:Genetic Complementation Test; D006824:Hybridization, Genetic; D018519:Meristem / Q000235:genetics / Q000254:growth & development; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D018515:Plant Leaves / Q000254:growth & development / Q000648:ultrastructure; D018520:Plant Shoots / Q000254:growth & development; D032107:Populus / Q000235:genetics* / Q000254:growth & development*; D034622:RNA Interference; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D029681:Arabidopsis Proteins; C410510:SHORT ROOT protein, Arabidopsis; D014157:Transcription Factors