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Poplar Ptab ZIP 1‐like enhances lateral root formation and biomass growth under drought stress
Author(s) -
Dash Madhumita,
Yordanov Yordan S.,
Georgieva Tatyana,
Tschaplinski Timothy J.,
Yordanova Elena,
Busov Victor
Publication year - 2017
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.13413
Subject(s) - biology , gene , lateral root , proline , mutant , arabidopsis , asparagine , genetically modified crops , phenotype , microbiology and biotechnology , transgene , botany , genetics , amino acid
Summary 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, 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 Ptab ZIP 1‐like ( Ptab ZIP 1L ) gene with highest homology to bZIP 1 from Arabidopsis. Ptab ZIP 1L is predominantly expressed in roots, particularly in zones where lateral root primordia ( LRP ) initiate and LR differentiate and emerge. Transgenics overexpressing Ptab ZIP 1L showed precocious LRP and LR development, while Ptab ZIP 1L suppression significantly delayed both LRP and LR formation. Transgenic overexpression and suppression of Ptab ZIP 1L 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 Ptab ZIP 1L mediates LR development and drought resistance through modulation of multiple metabolic pathways.