Journal Article

<i>ARAG1</i>, an ABA-responsive DREB gene, plays a role in seed germination and drought tolerance of rice

Lifeng Zhao, Yibing Hu, Kang Chong and Tai Wang

in Annals of Botany

Published on behalf of The Annals of Botany Company

Volume 105, issue 3, pages 401-409
Published in print March 2010 | ISSN: 0305-7364
Published online January 2010 | e-ISSN: 1095-8290 | DOI: http://dx.doi.org/10.1093/aob/mcp303
ARAG1, an ABA-responsive DREB gene, plays a role in seed germination and drought tolerance of rice

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  • Ecology and Conservation
  • Evolutionary Biology
  • Plant Sciences and Forestry

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Background and Aims

DREB proteins are involved mainly in plant responses to abiotic stresses such as cold, drought or high salinity as well as ABA signalling. However, the function of most rice DREB genes and the underlying molecular mechanisms controlling these responses remains elusive. In this study, ARAG1, a rice DREB gene, was functionally analysed.

Methods

Antisense and over-expression constructs of ARAG1 were introduced into rice by an Agrobacterium-mediated method. RT-PCR and western blot were used to detect ARAG1 accumulation in transgenics. PEG and ABA were used to test their response to abiotic stresses.

Key Results

ARAG1 was expressed in inflorescences, roots, immature embryos and germinating seeds, but not in coleoptiles, leaves or mature embryos. Drought stress and ABA treatment increased transcript levels of the gene rapidly. ARAG1 knockdown line was hypersensitive to ABA application during seed germination and seedling growth. However, the line over-expressing ARAG1 behaved similarly to wild type in these circumstances. Knockdown of ARAG1 weakened tolerance of the transgenic seedlings to drought stress, while over-expression of it increased the tolerance slightly. In addition, activity of α-amylases was enhanced in germinating seeds of the knockdown and over-expression lines.

Conclusions

These results indicate that ARAG1 was involved in the ABA signalling and stress responsive pathways.

Keywords: Abscisic acid (ABA); AP2/EREBP; ARAG1; DREB; drought; Oryza sativa

Journal Article.  5485 words.  Illustrated.

Subjects: Ecology and Conservation ; Evolutionary Biology ; Plant Sciences and Forestry

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