LST8 is a member of the widely conserved TOR kinase complex. This work shows that LST8 is important for plant growth as well as metabolic and developmental processes linked to changes in light conditions, probably by influencing the activity of the TOR complex. The conserved Target of Rapamycin (TOR) kinase forms high molecular mass complexes and is a major regulator of cellular adaptations to environmental cues. The Lethal with Sec Thirteen 8/G protein β subunit-like (LST8/GβL) protein is a member of the TOR complexes, and two putative LST8 genes are present in Arabidopsis thaliana, of which only one (LST8-1) is significantly expressed. The Arabidopsis LST8-1 protein is able to complement yeast lst8 mutations and interacts with the TOR kinase. Mutations in the LST8-1 gene resulted in reduced vegetative growth and apical dominance with abnormal development of flowers. Mutant plants were also highly sensitive to long days and accumulated, like TOR RNA interference lines, higher amounts of starch and amino acids, including proline and glutamine, while showing reduced concentrations of inositol and raffinose. Accordingly, transcriptomic and enzymatic analyses revealed a higher expression of genes involved in nitrate assimilation when lst8-1 mutants were shifted to long days. The transcriptome of lst8-1 mutants in long days was found to share similarities with that of a myo-inositol 1 phosphate synthase mutant that is also sensitive to the extension of the light period. It thus appears that the LST8-1 protein has an important role in regulating amino acid accumulation and the synthesis of myo-inositol and raffinose during plant adaptation to long days.
Mutations in the Arabidopsis Homolog of LST8/GβL, a Partner of the Target of Rapamycin Kinase, Impair Plant Growth, Flowering, and Metabolic Adaptation to Long Days[C][W]
Manon Moreau,Marianne Azzopardi,G. Clément,Thomas Dobrenel,Chloé Marchive,Charlotte Renne,M. Martin-Magniette,L. Taconnat,J. Renou,C. Robaglia,C. Meyer
Published 2012 in The Plant Cell
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- Publication year
2012
- Venue
The Plant Cell
- Publication date
2012-02-01
- Fields of study
Biology, Medicine, Environmental Science
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Semantic Scholar, PubMed
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