Analysis of common bean expressed sequence tags identifies sulfur metabolic pathways active in seed and sulfur-rich proteins highly expressed in the absence of phaseolin and major lectins

BMC Genomics

Research Article

Agnieszka Pajak¹  Ralph Chapman¹  Frédéric Marsolais²  Shangzhi Huang³  Fuqiang Yin⁴  Andrew Sharpe⁵ 

[1] Agriculture and Agri-Food Canada, Southern Crop Protection and Food Research Centre, 1391 Sandford St., N5V 4T3, London, ON, Canada;Agriculture and Agri-Food Canada, Southern Crop Protection and Food Research Centre, 1391 Sandford St., N5V 4T3, London, ON, Canada;Department of Biology, University of Western Ontario, N6A 5B7, London, ON, Canada;Department of Bioscience and Biotechnology, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, China;Department of Bioscience and Biotechnology, School of Life Sciences, Sun Yat-sen University, 510275, Guangzhou, China;Agriculture and Agri-Food Canada, Southern Crop Protection and Food Research Centre, 1391 Sandford St., N5V 4T3, London, ON, Canada;National Research Council of Canada, Plant Biotechnology Institute, 110 Gymnasium Place, S7N 0W9, Saskatoon, SK, Canada;

关键词: Common Bean;    Late Embryogenesis Abundant Protein;    Phaseolin;    Sulfur Amino Acid;    Stage VIII;   

DOI  :  10.1186/1471-2164-12-268

 received in 2010-12-13, accepted in 2011-05-26,  发布年份 2011

来源: Springer

【 摘 要 】

BackgroundA deficiency in phaseolin and phytohemagglutinin is associated with a near doubling of sulfur amino acid content in genetically related lines of common bean (Phaseolus vulgaris), particularly cysteine, elevated by 70%, and methionine, elevated by 10%. This mostly takes place at the expense of an abundant non-protein amino acid, S-methyl-cysteine. The deficiency in phaseolin and phytohemagglutinin is mainly compensated by increased levels of the 11S globulin legumin and residual lectins. Legumin, albumin-2, defensin and albumin-1 were previously identified as contributing to the increased sulfur amino acid content in the mutant line, on the basis of similarity to proteins from other legumes.ResultsProfiling of free amino acid in developing seeds of the BAT93 reference genotype revealed a biphasic accumulation of gamma-glutamyl-S-methyl-cysteine, the main soluble form of S-methyl-cysteine, with a lag phase occurring during storage protein accumulation. A collection of 30,147 expressed sequence tags (ESTs) was generated from four developmental stages, corresponding to distinct phases of gamma-glutamyl-S-methyl-cysteine accumulation, and covering the transitions to reserve accumulation and dessication. Analysis of gene ontology categories indicated the occurrence of multiple sulfur metabolic pathways, including all enzymatic activities responsible for sulfate assimilation, de novo cysteine and methionine biosynthesis. Integration of genomic and proteomic data enabled the identification and isolation of cDNAs coding for legumin, albumin-2, defensin D1 and albumin-1A and -B induced in the absence of phaseolin and phytohemagglutinin. Their deduced amino acid sequences have a higher content of cysteine than methionine, providing an explanation for the preferential increase of cysteine in the mutant line.ConclusionThe EST collection provides a foundation to further investigate sulfur metabolism and the differential accumulation of sulfur amino acids in seed of common bean. Identification of sulfur-rich proteins whose levels are elevated in seed lacking phaseolin and phytohemagglutinin and sulfur metabolic genes may assist the improvement of protein quality.

【 授权许可】

Unknown   
© Yin et al; licensee BioMed Central Ltd. 2011. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.