NAC Transcription Factors from Soybean Essay

The Soybean (Glycine max L.), dubbed the "miracle crop", is one of the most ancient crops of China, and has been used by several oriental cultures for centuries in many ways as one of the most chief resource of protein and oil (Tran L.S. and Mochida K. 2010). Nowadays, soybeans are used as ingredients in human food, plastics, animal food, fuel, engine oils, paints, and many other products (Singh & Singh 2010 Tran L.S. and Mochida K. 2010).
Plants are affected to countless abiotic and biotic stresses in the natural environment, which are regulated by gene specific transcription factors with the aim of activate or repress the transcription apparatus by binding at target gene promoters (Tran L. S. et al., 2010 Atkinson N.J. et al., 2012). Transcription factors are clustered into families on the basis of sequence similarities, mainly often in the DNA binding domain. NAC-domain transcription factors (NACs) are important to regulation of several aspects of plant development as well as flower maturation, root formation, meristem formation and organ division. NAC proteins are specific transcriptions factors of plants, which holding a highly conserved N-terminal sequence designated the NAC domain and includes the DNA binding domain (DBD) (J. L. Riechmann et al., 2000 Duval M et al., 2002) and The transcriptional regulatory (TR) domain of the NAC proteins is usually present in the C-terminal end and can function to activate (Lu PL et al., 2007 Puranik S et al., 2011 Tran LS et al., 2004) or to repress transcription (Delessert C et al., 2005 Kim SG et al., 2007 Yamaguchi M et al., 2010). The NAC name is derived from the NO APICAL MERISTEM (NAM) gene from petunia and the Arabidopsis genes CUP-SHAPED COTYLEDON2 along with (CUC2) ATAF1/ATAF2 (Aida et al., 1997).The NAC domain consisting of approximately 160 amino acid residues, the NAC domain contains five sub domains referred to as A to E (Ernst et al., 2004 Kikuchi et al., 2000 Ooka et al., 2003). NAC domain proteins were involved as one of the largest plant specific transcription factors, epitomized through 117 genes in Arabidopsis (Hu R et al. 2010), 151 genes in rice (Oryza sativa) (Ooka et al., 2003), 163 genes in Populus (Le DT et al., 2011) and 152 genes in the soybean genome (Nuruzzaman M et al., 2010). NAC transcription factors have numerous functions, several of which have been well clarified in Arabidopsis and Oryza sativa (Tran LS et al., 2009).
NAC TFs are plant-specific proteins that are known to play a role in response to biotic and abiotic stress, comprising drought (Nakashima K. et al., 2012 Nuruzzaman M. et al., 2013). For example, in Arabidopsis over-expression of (ANAC019, ANAC055 and ANAC072) display a significant improvement in senescence and drought tolerance of transgenic Arabidopsis (Tran L.S. et al., 2004 Jensen MK et al., 2010 Hickman R et al., 2013). Previous genes have been provoked by ABA, (HSFs) heat stress transcription factors, JA- signaling and diverse abiotic stress (Qingmei Guan et al., 2014 Jensen MK and Skriver 2014) )