Dihydroxyacid dehydratase is important for gametophyte development and disruption causes increased susceptibility to salinity stress in Arabidopsis
| Autor: | Luguang Jiang, Xiufeng Yan, Qiuying Pang, Yan He, Chun Zhang, Shoucai Wang, Sixue Chen |
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| Rok vydání: | 2014 |
| Předmět: |
Salinity
root development Physiology Mutant Arabidopsis branched-chain amino acid (BCAA) Plant Science Sodium Chloride gametogenesis Gene Expression Regulation Plant Stress Physiological dihydroxyacid dehydratase (DHAD) Arabidopsis thaliana Hydro-Lyases chemistry.chemical_classification Gametophyte Gene knockdown biology Arabidopsis Proteins biology.organism_classification Amino acid chemistry Biochemistry Essential gene Osmolyte salt stress Germ Cells Plant Research Paper |
| Zdroj: | Journal of Experimental Botany |
| ISSN: | 1460-2431 |
| Popis: | Highlight Molecular characterization of dihydroxyacid dehydratase in Arabidopsis reveals its important roles in gametophyte and root development, as well as involvement in salinity stress resistance. Dihydroxyacid dehydratase (DHAD) catalyses a key step in the branched-chain amino acid (BCAA) biosynthetic pathway that exists in numerous organisms, including bacteria, fungi, and plants, but not humans. In Arabidopsis thaliana, DHAD is encoded by a single gene (AT3G23940), but its biological function in controlling plant development remains uncharacterized. In this study, we showed that DHAD is highly expressed in most vegetative and reproductive tissues. It is an essential gene, and complete disruption caused partial sterility in both male and female gametophyte phases. In addition, reduced expression of DHAD in knockdown mutants resulted in a reduction in the accumulation of all three BCAAs in roots and, as a consequence, led to a shorter root phenotype, which could be restored by an exogenous supplement of free BCAAs. Interestingly, the knockdown mutants became hypersensitive to salt stress, not to heavy metal stress, implying that BCAAs may act as osmolytes in salt tolerance. This would be the second amino acid shown to confer such a function in addition to the well-documented proline. Our results provide evidence that BCAA biosynthesis plays important roles in gametophyte and root development, and BCAA homeostasis contributes to the adaptation of Arabidopsis to salinity stress. |
| Databáze: | OpenAIRE |
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