Light-dependent gene expression for proteins in the respiratory chain of potato leaves

Svensson, AS Rasmusson, AG

As. Svensson et Ag. Rasmusson, Light-dependent gene expression for proteins in the respiratory chain of potato leaves, PLANT J, 28(1), 2001, pp. 73-82

40

INGLESE

Article

Plant Sciences","Animal & Plant Sciences

PLANT JOURNAL

0960-7412 → ACNP

28

1

2001

73 - 82

ISI

0960-7412(200110)28:1<73:LGEFPI>2.0.ZU;2-#

Expression of genes for respiratory chain dehydrogenases was investigated i n potato (Solanum tuberosum L. cv. Desiree) leaves. The recently characteri zed nda1 and ndb1 genes, homologues to genes encoding the non-proton pumpin g respiratory chain NADH-dehydrogenases of Escherichia coli and yeast, were compared to genes encoding catalytic subunits of the proton-pumping NADH d ehydrogenase (complex I). As leaves develop from young to mature, the nda1 transcript level increases, accompanied by an elevation in immunodetected N DA protein and internal rotenone-insensitive NADH oxidation. The other inve stigated transcripts, proteins and NAD(P)H oxidation activities were essent ially unchanged. A variation in transcript level, specific for nda1, is see n at different times of the day with highest expression in the morning. Thi s variation also influences the apparent developmental induction. Further, the nda1 mRNA in leaves specifically and completely disappears during dark treatment, with a rapid reinduction when plants are returned to light. Corr esponding immunodetected NDA protein is specifically decreased in mitochond ria isolated from dark-treated plants, accompanied by a lower capacity for internal rotenone-insensitive NADH oxidation, Complete light dependence and diurnal changes in expression have previously not been reported for genes encoding respiratory chain proteins. Qualitatively similar to NDA, the alte rnative oxidase showed developmental induction and light dependence. In add ition to the specific change in nda1, a general, slower down-regulation in darkness was seen for the other NAD(P)H dehydrogenase genes. The nda1 expre ssion during development, and in response to light, indicates a specific ro le of the encoded enzyme in the photosynthetically associated mitochondrial metabolism.