Abstract
Seeds are the most important plant storage organ and play a central role in the life cycle of plants. Since little is known about the protein composition of rice (Oryza sativa) seeds, in this work we used proteomic methods to obtain a reference map of rice seed proteins and identify important molecules. Overall, 480 reproducible protein spots were detected by two-dimensional electrophoresis on pH 4–7 gels and 302 proteins were identified by MALDI-TOF MS and database searches. Together, these proteins represented 252 gene products and were classified into 12 functional categories, most of which were involved in metabolic pathways. Database searches combined with hydropathy plots and gene ontology analysis showed that most rice seed proteins were hydrophilic and were related to binding, catalytic, cellular or metabolic processes. These results expand our knowledge of the rice proteome and improve our understanding of the cellular biology of rice seeds.
Highlights
Rice (Oryza sativa L.) is the main food source for more than two-third of the world’s population (Sasaki and Burr, 2000), especially in Southeast Asia (Nwugo and Huerta, 2011; Wang et al, 2011)
Proteomic analysis was first described by Wilkins and Williams (1994) and seeks to study all proteins expressed in a cell, tissue or organism at a specific time or under specific circumstances by maximizing protein separation and identification (Wilkins et al, 1998)
The analysis of 2-DE gels with PDQuest software detected 480 reproducible protein spots, most of which were distributed near the center of the gels (Figure 1)
Summary
Rice (Oryza sativa L.) is the main food source for more than two-third of the world’s population (Sasaki and Burr, 2000), especially in Southeast Asia (Nwugo and Huerta, 2011; Wang et al, 2011). With the completion of the rice genome sequencing program, rice has become the model organism in molecular biological research of monocotyledons (Agrawal and Rakwal, 2011; Li et al, 2011). Many studies have investigated the functional genomics of rice. Traditional functional genomics have investigated mainly the changes in mRNA abundance in histiocytes. Because of transcriptional regulation, mRNA levels do not provide a true indication of protein expression levels (Jugran et al, 2010; Ding et al, 2012). Proteomic analysis was first described by Wilkins and Williams (1994) and seeks to study all proteins expressed in a cell, tissue or organism at a specific time or under specific circumstances by maximizing protein separation and identification (Wilkins et al, 1998)
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