N plastids are cytochrome b6f complex, photosystem I and ferredoxin-thioredoxin reductase [4-7]. Three different systems for [Fe-S] clusters biosynthesis have been identified in bacteria, all of them share cysteine desulfurases and [Fe-S] NIK333 web cluster scaffold proteins. Those systems are referred to as NIF (nitrogen fixation system), ISC (iron-sulfur cluster assembly system) and SUF (sulfur mobilization system) [8-10]. There are several mitochondrial proteins homologous to the bacterial ISC system, including a group I NifS-like proteins, supporting the evolutionary relationship between a?2011 Heis et al; licensee 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.Heis et al. BMC Plant Biology 2011, 11:166 http://www.biomedcentral.com/1471-2229/11/Page 2 ofProteobacteria and mitochondria [5]. In yeast, it has been shown that mitochondria are the primary site of [Fe-S] cluster formation; however, these organelles not only produce their own Fe-S proteins, but are also required for the maturation of cytosolic Fe-S proteins [11]. In the chloroplast, five different [Fe-S] cluster types are found in various proteins, and this organelle possesses its own machinery for [Fe-S] biosynthesis which is most similar to those found in cyanobacteria containing the SUF system and the cysteine desulfurase which is similar to the bacterial SufS, a group II NifS-like protein [12,13]. Cysteine desulfurase is a pyridoxal 5′-phosphate (PLP)dependent enzyme that catalyzes the conversion of Lcysteine to L-alanine and sulfane sulfur. This occurs through the formation of a protein-bound cysteine persulfide intermediate on a conserved cysteine residue [14,15]. Considering that sulfide and free iron are toxic to the cell, intracellular concentrations are thought to be extremely low. Besides being involved in sulfur mobilization, cysteine desulfurase is proposed to be involved in cellular iron homeostasis [16-18]. ISD11 is an essential mitochondria matrix protein, a component of the ISC-assembly machinery, and is conserved in eukaryotes, but not found in prokaryotes. This protein forms a stable complex with NFS1, increases NFS1 activity, and is essential for the enzymatic activity of several Fe-S proteins [19,20]. Sulfur-containing defense compounds (SDCs) are involved in stress response and their synthesis involve several genes for sulfur assimilation [21]. It is hypothesized that soybean (Glycine max) has gone through at least two polyploidy and diploidization events, being considered a paleopolyploid [22], still presenting many gene duplications [23]. Various stresses can adversely affect plant growth and crop production, such as low temperature which modifies membrane lipid composition, thus affecting mitochondria respiratory function [24] and presumably photosynthesis. PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/28945807 Expression of various plant genes is regulated by abiotic environmental stresses such as cold. Many cis-acting elements involved in stress response and stress-inducible genes contain cis-acting elements in their promoter regions have been described. Here, we identified the soybean cysteine desulfurase genes by sequence comparison. Furthermore, we investigate the responsiveness of these genes under biotic and abiotic stresses, as well as transcript distribution in di.
