벼의 스트레스에 관여하는 WDL 및 OsPUB15 유전자의 기능 연구
- 벼의 스트레스에 관여하는 WDL 및 OsPUB15 유전자의 기능 연구
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- Global climate changes cause abiotic stresses, which are the greatest threat to cereal production and security in worldwide. Especially, drought accelerates the salinity of irrigated land, continues to expand desertification. Better knowledge of the molecular and genetic bases of the mechanisms promoting tolerance to abiotic stress will help in improving a plant's capacity to adapt to a limited environment, which in turn will enable an increase in the current production levels. Here, I report characteration of two rice mutants, which showed altered response to abiotic stresses. One, named wilted dwarf and lethal 1 (wdl1), was dwarfed and died at the seedling stage because of an increased rate of water loss. This mutant had smaller stomatal and pavement cells, suggesting that WDL1 affects epidermal cell differentiation. T-DNA was inserted into a gene encoding a protein within the GDSL lipase superfamily. SEM analysis showed that the leaves of this mutant had a disorganized crystal wax layer. Cross-sectional analysis revealed loose packing of the cuticle and irregular thickness of the cell wall. Detailed analysis of the epicuticular wax showed no significant changes in the total amount and amounts of each monomer, and in the levels of lipid polymers, including cutin and other covalently bound lipids, attached to the cell wall. These results indicate that WDL1 is involved in cutin organization, affecting depolymerizable components. The other mutant was hypersensitive to oxidizing stress, and showed severe growth retardation and a seedling-lethal phenotype. This mutant gene, Oryza sativa Plant U-Box15 (OsPUB15), encoded a protein of the Class II PUB family. Self-ubiquitination assays showed that bacterially expressed MBP-OsPUB15 had E3 ubiquitin ligase activity. Mutant seeds did not produce primary roots, and their shoot development was significantly delayed. Transgenic plants expressing the OsPUB15 antisense transcript phenocopied these mutant characters. The abnormal phenotypes were partially rescued by two antioxidants, catechin and ascorbic acid. Germinating seeds in the dark also recovered the rootless defect. The levels of H2O2 and oxidized proteins were higher in the knockout mutant than in the wild type. OsPUB15 transcript levels increased upon H2O2, salt, and drought stresses
the plants overexpressing the gene grew better than the wild type under high salinity. These results indicate that PUB15 is a regulator that reduces ROS stress and cell death.
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