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Title: Poplar PtabZIP1-like enhances lateral root formation and biomass growth under drought stress

Developing drought-resistance varieties is a major goal for bioenergy crops, such as poplar (Populus), which will be grown on marginal lands with little or no water input. Root architecture can affect drought resistance, but few genes that affect root architecture in relation to water availability have been identified. Here in this study, using activation tagging in the prime bioenergy crop poplar, we have identified a mutant that overcomes the block of lateral root (LR) formation under osmotic stress. Positioning of the tag, validation of the activation and recapitulation showed that the phenotype is caused by the poplar PtabZIP1-like (PtabZIP1L) gene with highest homology to bZIP1 from Arabidopsis. PtabZIP1L is predominantly expressed in roots, particularly in zones where lateral root primordia (LRP) initiate and LR differentiate and emerge. Transgenics overexpressing PtabZIP1L showed precocious LRP and LR development, while PtabZIP1L suppression significantly delayed both LRP and LR formation. Transgenic overexpression and suppression of PtabZIP1L also resulted in modulation of key metabolites like proline, asparagine, valine and several flavonoids. Consistently, expression of both of the poplar Proline Dehydrogenase orthologs and two of the Flavonol Synthases genes was also increased and decreased in overexpressed and suppressed transgenics, respectively. These findings suggest that PtabZIP1L mediatesmore » LR development and drought resistance through modulation of multiple metabolic pathways.« less
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [1] ;  [1]
  1. Michigan Technological Univ., Houghton, MI (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Bioscience Division
Publication Date:
Grant/Contract Number:
AC05-00OR22725; SC0008462; 2009-65504-05767
Type:
Accepted Manuscript
Journal Name:
The Plant Journal
Additional Journal Information:
Journal Volume: 89; Journal Issue: 4; Journal ID: ISSN 0960-7412
Publisher:
Society for Experimental Biology
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23); US Department of Agriculture (USDA)
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; PtabZIP1-like; lateral root growth; Flavonol Synthases; flavonoid biosynthesis; Populus tremula × P. alba; drought resistance
OSTI Identifier:
1349610
Alternate Identifier(s):
OSTI ID: 1401028