Over-expression of the rice OsAMT1-1 gene increases ammonium uptake and content, but impairs growth and development of plants under high ammonium nutrition

Date

2006

Authors

Hoque, Mohammed
Masle, Josette
Udvardi, Michael K
Ryan, Peter R
Upadhyaya, Narayana M

Journal Title

Journal ISSN

Volume Title

Publisher

CSIRO Publishing

Abstract

A transgenic approach was undertaken to investigate the role of a rice ammonium transporter (OsAMT1-1) in ammonium uptake and consequent ammonium assimilation under different nitrogen regimes. Transgenic lines overexpressing OsAMT1-1 were produced by Agrobacterium-mediated transformation of two rice cultivars, Taipei 309 and Jarrah, with an OsAMT1-1 cDNA gene construct driven by the maize ubiquitin promoter. Transcript levels of OsAMT1-1 in both Taipei 309 and Jarrah transgenic lines correlated positively with transgene copy number. Shoot and root biomass of some transgenic lines decreased during seedling and early vegetative stage compared to the wild type, especially when grown under high (2 mM) ammonium nutrition. Transgenic plants, particularly those of cv. Jarrah recovered in the mid-vegetative stage under high ammonium nutrition. Roots of the transgenic plants showed increased ammonium uptake and ammonium content. We conclude that the decreased biomass of the transgenic lines at early stages of growth might be caused by the accumulation of ammonium in the roots owing to the inability of ammonium assimilation to match the greater ammonium uptake.

Description

Keywords

Keywords: Ammonia; Bacteria; DNA; Growth kinetics; Plants (botany); Ammonium transporters; Ammonium uptake; Oryza sativa; OSAMT1-1 over-expression; Genes; rice; transgenic plant; Ammonia; Bacteria; Genes; Growth; Nucleic Acids; Plants; Agrobacterium; Eucalyptus mar Ammonium transporter; Ammonium uptake; Oryza sativa; OSAMT1-1 over-expression

Citation

Source

Functional Plant Biology

Type

Journal article

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2037-12-31