Isoflavonoid metabolism Essay

solubility and stability of the aglycone, allowing for its proper transport to cell vacuoles (Jones and Vogt 2001). These conjugation reactions are catalyzed by isoflavonoidspecific glycosyltransferase and malonyltransferases (Dhaubhadel et al. 2008). Isoflavonoids are found in all organs and tissues of soybean plants. However, their levels vary depending on tissue types and developmental stages. Mature seeds and leaves accumulate the highest levels of isoflavonoids compared to other tissues. Accumulation of isoflavonoids and the key biosynthetic gene expression increases in developing soybean embryos as they approach seed maturity (Dhaubhadel et al.2003).
There is a need of day that these compounds must be included in to the daily human consumed food commodities like vegetables, fruits and grains due to their significant role in plant growth and human health. Because many pharmacological benefits have been associated with these flavonoids (Lu et al., 2013). The genetic engineering play important role for the development of such crops. But before introducing, the knowledge about genes, transcription factors, transporter involved in their biosynthesis pathway is very important. Considerable level of progress has been done by isolating and characterizing most of the structural and regulatory genes. Detailed genetic and metabolic engineering study of such genes make easy to introduce the important isoflavonoid compounds in the target plant species and also improve their level in the existing plants.
Soybean is a paleopolyploid with a genome size of approximately 978 Mb. The whole genome sequencing of soybean was completed in 2010 that revealed 56,044 protein coding loci located on 20 different chromosomes (Schmutz et al. 2010). Approximately 88,647 transcripts have been predicted and their tissue specific expression patterns are available in public database (http//www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE29163) (Vadivel et al., 2015). Even though generation of stable transgenic soybean plants are time consuming and tedious, functional characterization of genes using hairy roots is well established in soybean. These tools and resources provide an excellent opportunity to study isoflavonoid metabolism in soybean (Vadivel et al., 2015).
Biosynthesis When different plant tissues subjected to different stress conditions like high intensity of light, cold, deficiency of nutrients, attack of different pathogens etc, it leads to the production of different flavonoids (Hernandez et al., 2009). Keeping in view the importance of flavonoids, special attention has been given to the study of genetics and biochemistry biosynthetic pathway of flavonoids in different plants (Korkina, 2007 Ververidis et al., 2007 Crozieret al.,2009). These studies showed that composition of flavonoids is varying species to species and even different organs of the same plant (Holton and Cornish, 1995, Espley et al., 2007 Bogset al., 2006 Castellarin et al., 2006). The biosynthetic pathway of flavonoids has been broadly studied in a number of publications (Holton and Cornish, 1995 WinkelShirley, 2001 Koes et al., 2005 Gould and Lister, 2006).
As mentioned above that Isoflavonoids are synthesized via a legumespecific branch of the phenylpropanoid pathway (Fig. 1). The general phenylpropanoid pathway is the most extensively studied biosynthetic pathway in plants that leads into the production of a plethora of specialized metabolites such as flavonoids, lignins, condensed