Abnormal chloroplast development and growth inhibition in rice thioredoxin m knock-down plants.
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 beta-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 micromol 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.
Chi
Yong Hun
YH
Division of Applied Life Science (BK21 Program), EB-NCRC and Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, Korea.
Moon
Jeong Chan
JC
Park
Jin Ho
JH
Kim
Ho-Seung
HS
Zulfugarov
Ismayil S
IS
Fanata
Wahyu Indra
WI
Jang
Ho Hee
HH
Lee
Jung Ro
JR
Lee
Young Mee
YM
Kim
Sun Tae
ST
Chung
Yong-Yoon
YY
Lim
Chae Oh
CO
Kim
Jae-Yean
JY
Yun
Dae-Jin
DJ
Lee
Choon-Hwan
CH
Lee
Kyun Oh
KO
Lee
Sang Yeol
SY
D002338:Carotenoids / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D054479:Chloroplast Thioredoxins / Q000235:genetics / Q000378:metabolism*; D002736:Chloroplasts / Q000378:metabolism* / Q000648:ultrastructure; D004229:Dithiothreitol / Q000378:metabolism; D015180:Electrophoresis, Gel, Two-Dimensional; D017343:Genes, Plant; D006861:Hydrogen Peroxide / Q000378:metabolism; D012275:Oryza / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D054464:Peroxiredoxins / Q000378:metabolism; D010641:Phenotype; D010788:Photosynthesis; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D011972:Receptor, Insulin / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013379:Substrate Specificity
D054479:Chloroplast Thioredoxins; D010940:Plant Proteins; D020033:Protein Isoforms; D012333:RNA, Messenger; D018749:RNA, Plant; D011994:Recombinant Proteins; D002734:Chlorophyll; D002338:Carotenoids; D006861:Hydrogen Peroxide; D054464:Peroxiredoxins; D011972:Receptor, Insulin; D004229:Dithiothreitol