Proteomic identification of small, copper-responsive proteins in germinating embryos of Oryza sativa |
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Authors: | Hongxiao Zhang Chunlan Lian Zhenguo Shen |
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Affiliation: | 1College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China;2Asian Natural Environmental Science Center, The University of Tokyo, 1-1-8 Midori-cho, Nishitokyo, Tokyo 188-0002, Japan |
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Abstract: | Background and AimsAlthough copper (Cu) is an essential micronutrient for plants and algae, excess Cu is toxic to most plants and can cause a wide range of deleterious effects. To investigate the response of rice (Oryza sativa) to Cu stress, a proteomic approach was used to analyse Cu stress-induced changes in the expression of low molecular-weight proteins in germinating rice seed embryos.MethodsRice seeds were germinated in the presence or absence of 200 µm Cu for 6 d, and embryos, including newly formed shoots and radicles, were isolated. After proteins were extracted from the germinating embryos and separated by two-dimensional PAGE, 16 proteins in the 6- to 25-kDa range were identified using MALDI-TOF mass spectrometry.Key Results and ConclusionsThirteen of the proteins identified, including metallothionein-like protein, membrane-associated protein-like protein, putative wall-associated protein kinase, pathogenesis-related proteins and the putative small GTP-binding protein Rab2, were up-regulated by Cu stress. Three proteins, a putative small cytochrome P450 (CYP90D2), a putative thioredoxin and a putative GTPase, were down-regulated by Cu stress. As far as is known, this study provides the first proteomic evidence that metallothionein and CYP90D2 are Cu-responsive proteins in plants. These findings may lead to a better understanding of plant molecular responses to toxic metal exposure.Key words: Copper, metallothionein, rice, Oryza sativa, proteomics, seed germination |
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