Expression of the plastid ndhF gene product in photosynthetic and non-photosynthetic tissues of developing barley seedlings.
A fragment of the NDH-F subunit of the plastid NAD(P)H dehydrogenase complex (NAD(P)H-plastoquinone-oxidoreductase) from barley was expressed as a fusion protein in Escherichia coli and an antibody to the fusion protein was prepared. Western blot analysis using the anti-NDH-F antibody showed specificity towards a plastid polypeptide of approximately 70 kDa present in both photosynthetic and non-photosynthetic barley tissue. The polypeptide was found in thylakoid membranes of green leaves whereas in etiolated leaves it was shown to be associated with the membrane fraction of etioplasts. NDH-F levels were higher in roots and etiolated tissue than in greening or young leaves. During leaf ontogeny, NDH-F levels decreased from young to mature tissue but increased during senescence. The accumulation of NDH-F in thylakoids of young leaves was stimulated by photooxidative treatment. The results indicate a high degree of expression of plastid ndh genes (which encode NAD(P)H dehydrogenase subunits) in non-photosynthetic plastids and under conditions which impair the photosynthetic activity of chloroplasts. In addition to its putative implication in photosynthetic electron transport, a non-photosynthetic role, such as chlororespiration, is proposed for the plastid NAD(P)H dehydrogenase complex.
Catalá
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Departamento de Biología Vegetal, Universidad de Alcalá de Henares, Madrid, Spain.
Sabater
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B
Guéra
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D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D003001:Cloning, Molecular; D004926:Escherichia coli; D015870:Gene Expression; D017343:Genes, Plant; D001467:Hordeum / Q000196:embryology / Q000201:enzymology* / Q000235:genetics; D008969:Molecular Sequence Data; D009245:NADH Dehydrogenase / Q000235:genetics*; D009252:NADPH Dehydrogenase / Q000235:genetics*; D010788:Photosynthesis; D010940:Plant Proteins / Q000235:genetics*; D018087:Plastids; D012639:Seeds / Q000201:enzymology
D001426:Bacterial Proteins; D010940:Plant Proteins; C081468:NdhF protein, bacteria; C489904:NdhF protein, plant; D009252:NADPH Dehydrogenase; D009245:NADH Dehydrogenase