Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/50321
標題: Lily ASR protein-conferred cold and freezing resistance in Arabidopsis
作者: Hsu, Y.F.
王國祥
Yu, S.C.
Yang, C.Y.
Wang, C.S.
關鍵字: ASR
Cold-responsive genes
Enzyme protection
Lilium longiflorum
Transgenic plants
salt-stress
expression profiles
gene-expression
lea proteins
water-stress
dna-binding
in-vitro
temperature
drought
dehydrogenase
期刊/報告no:: Plant Physiology and Biochemistry, Volume 49, Issue 9, Page(s) 937-945.
摘要: The lily LLA23 protein is a member of the abscisic acid, stress and ripening-induced (ASR) protein family. Constitutive overexpression of LLA23 under the cauliflower mosaic virus 35S promoter confers cold and freezing tolerance in Arabidopsis. The phenotypical growth and survival percentage of the two transgenic 35S::LLA23 plants showed higher resistance to cold and freezing conditions than those of wild-type (WT) plants. The electrolyte leakage in WT leaves increased by approximately fourfold at -2 degrees C relative to that at 22 degrees C whereas both transgenic leaves showed little ion leakage under the same conditions. A microarray analysis of LLA23-overexpressing transgenic line, 35S::LLA23E, under normal growing conditions was previously conducted by Yang et al. (Protoplasma, 2008, 233:241-254). Microarray analysis showed that 12 cold-responsive genes are upregulated and 25 cold-responsive genes are downregulated by lily ASR. Many ASR-regulated genes encode proteins involved in the classes of defense/stress-related, transcription, and metabolism. Quantitative polymerase chain reaction analysis confirms the changes in mRNA levels observed in the microarray analysis. Thus, our results provide in vivo evidence implying that LLA23 mediates cold/freezing stress-responsive signaling. To gain further insight into the functions of LLA23 protein, an in vitro enzyme protection assay was used in which lactate dehydrogenase and malate dehydrogenase were subjected to unfavorable conditions. The assay revealed that both enzyme activities were significantly retained with the addition of LLA23, which was superior to either trehalose or BSA, suggesting that the LLA23 protein can protect enzymatic activities against freeze-thaw cycles. The 35S::LLA23 seedlings also exhibited enzyme activity superior to WT at -4 degrees C. These results suggest that LLA23 may act as an osmoprotectant as well as a transcription factor to confer 35S::LLA23 plants enhanced cold and freezing resistance. (C) 2011 Elsevier Masson SAS. All rights reserved.
URI: http://hdl.handle.net/11455/50321
ISSN: 0981-9428
文章連結: http://dx.doi.org/10.1016/j.plaphy.2011.07.002
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