In:
Plant Physiology, Oxford University Press (OUP), Vol. 148, No. 2 ( 2008-10-06), p. 808-817
Abstract:
Plant cells contain several thioredoxin isoforms that are characterized by subcellular localization and substrate specificity. Here, we describe the functional characterization of a rice (Oryza sativa) thioredoxin m isoform (Ostrxm) using a reverse genetics technique. Ostrxm showed green tissue-specific and light-responsive mRNA expression. Ostrxm was localized in chloroplasts of rice mesophyll cells, and the recombinant protein showed dithiothreitol-dependent insulin β-chain reduction activity in vitro. RNA interference (RNAi) of Ostrxm resulted in rice plants with developmental defects, including semidwarfism, pale-green leaves, abnormal chloroplast structure, and reduced carotenoid and chlorophyll content. Ostrxm RNAi plants showed remarkably decreased F v/F m values under high irradiance conditions (1,000 μmol m−2 s−1) with delayed recovery. Two-dimensional electrophoresis and matrix-assisted laser-desorption/ionization time-of-flight analysis showed that the levels of several chloroplast proteins critical for photosynthesis and biogenesis were significantly decreased in Ostrxm RNAi plants. Furthermore, 2-Cys peroxiredoxin, a known target of thioredoxin, was present in oxidized forms, and hydrogen peroxide levels were increased in Ostrxm RNAi plants. The pleiotropic effects of Ostrxm RNAi suggest that Ostrxm plays an important role in the redox regulation of chloroplast target proteins involved in diverse physiological functions.
Type of Medium:
Online Resource
ISSN:
1532-2548
DOI:
10.1104/pp.108.123547
Language:
English
Publisher:
Oxford University Press (OUP)
Publication Date:
2008
detail.hit.zdb_id:
2004346-6
detail.hit.zdb_id:
208914-2
SSG:
12
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