Cold-Regulated Cereal Chloroplast Late Embryogenesis Abundant-Like Proteins. Molecular Characterization and Functional Analyses
AUTOR(ES)
NDong, Christian
FONTE
American Society of Plant Physiologists
RESUMO
Cold acclimation and freezing tolerance are the result of complex interaction between low temperature, light, and photosystem II (PSII) excitation pressure. Previous results have shown that expression of the Wcs19 gene is correlated with PSII excitation pressure measured in vivo as the relative reduction state of PSII. Using cDNA library screening and data mining, we have identified three different groups of proteins, late embryogenesis abundant (LEA) 3-L1, LEA3-L2, and LEA3-L3, sharing identities with WCS19. These groups represent a new class of proteins in cereals related to group 3 LEA proteins. They share important characteristics such as a sorting signal that is predicted to target them to either the chloroplast or mitochondria and a C-terminal sequence that may be involved in oligomerization. The results of subcellular fractionation, immunolocalization by electron microscopy and the analyses of target sequences within the Wcs19 gene are consistent with the localization of WCS19 within the chloroplast stroma of wheat (Triticum aestivum) and rye (Secale cereale). Western analysis showed that the accumulation of chloroplastic LEA3-L2 proteins is correlated with the capacity of different wheat and rye cultivars to develop freezing tolerance. Arabidopsis was transformed with the Wcs19 gene and the transgenic plants showed a significant increase in their freezing tolerance. This increase was only evident in cold-acclimated plants. The putative function of this protein in the enhancement of freezing tolerance is discussed.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=166530Documentos Relacionados
- Molecular and Biochemical Characterization of a Cold-Regulated Phosphoethanolamine N-Methyltransferase from Wheat1
- Constitutive expression of the cold-regulated Arabidopsis thaliana COR15a gene affects both chloroplast and protoplast freezing tolerance
- A Mitochondrial Complex I Defect Impairs Cold-Regulated Nuclear Gene Expression
- Cotton Lea5 and Lea14 encode atypical late embryogenesis-abundant proteins.
- Expression patterns and promoter activity of the cold-regulated gene ci21A of potato.