Eucalypt NADP-Dependent Isocitrate Dehydrogenase1 : cDNA Cloning and Expression in Ectomycorrhizae
AUTOR(ES)
Boiffin, Vincent
FONTE
American Society of Plant Physiologists
RESUMO
NADP-dependent isocitrate dehydrogenase (NADP-ICDH) activity is increased in roots of Eucalyptus globulus subsp. bicostata ex Maiden Kirkp. during colonization by the ectomycorrhizal fungus Pisolithus tinctorius Coker and Couch. To investigate the regulation of the enzyme expression, a cDNA (EgIcdh) encoding the NADP-ICDH was isolated from a cDNA library of E. globulus-P. tinctorius ectomycorrhizae. The putative polypeptide sequence of EgIcdh showed a high amino acid similarity with plant NADP-ICDHs. Because the deduced EgICDH protein lacks an amino-terminal targeting sequence and shows highest similarity to plant cytosolic ICDHs, it probably represents a cytoplasmic isoform. RNA analysis showed that the steady-state level of EgIcdh transcripts was enhanced nearly 2-fold in ectomycorrhizal roots compared with nonmycorrhizal roots. Increased accumulation of NADP-ICDH transcripts occurred as early as 2 d after contact and likely led to the observed increased enzyme activity. Indirect immunofluorescence microscopy indicated that NADP-ICDH was preferentially accumulated in the epidermis and stele parenchyma of nonmycorrhizal and ectomycorrhizal lateral roots. The putative role of cytosolic NADP-ICDH in ectomycorrhizae is discussed.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=34948Documentos Relacionados
- The Inheritance of Enzyme Variants for Tyrosine Aminotransferase, Nadp-Dependent Malate Dehydrogenase, Nadp-Dependent Isocitrate Dehydrogenase, and Tetrazolium Oxidase in TETRAHYMENA PYRIFORMIS, Syngen 1
- Peroxisomal NADP-Dependent Isocitrate Dehydrogenase. Characterization and Activity Regulation during Natural Senescence1
- The NADP-Dependent Methylene Tetrahydromethanopterin Dehydrogenase in Methylobacterium extorquens AM1
- Purification and properties of NADP-dependent glutamate dehydrogenase from Ruminococcus flavefaciens FD-1.
- Cloning and expression analysis of the cytosolic NADP(+)-dependent isocitrate dehydrogenase from potato. Implications for nitrogen metabolism.