Next Generation transcriptome sequencing approach for identification of metabolic and gene regulatory network of Halliwell Asada Pathway in relation to antioxidant activity in finger millet Eleusine coracana

Abstract

Antioxidants play an important role in preventing oxidative damage caused by reactive oxygen newlinespecies and keeps people healthy. Therefore, it is very important to understand the genes newlineassociated with oxidative damages, which can be used to improve human health. In present newlinestudy, finger millet has been selected which is an antioxidant crop having exceptionally-high newlinecalcium content. We identified 30 antioxidant genes viz. APX, DHAR, MDHAR, GR and SOD newlinealongwith their isoforms from RNA-Seq data of two contrasting genotypes viz. GP-1 (low Ca2+) newlineand GP-45 (high Ca2+) of finger millet. These genes were structurally and functionally newlinecharacterized and compared with other cereal crops such as rice, sorghum and foxtail millet. The newlinephylogenetic analysis has further shown that all genes are conserved and are classified into 5 newlinespecific groups, each of which shares almost similar motifs and domains. These domains such as newlineascorbate peroxidase, glutathione dehydrogenase, glutathione reductase, Fe and Cu-Zn newlinesuperoxide dismutase play significant role in antioxidant activity and drought tolerance. These newlinegenes were mainly localized in chloroplast and cytoplasm which proves that both may be newlinefunctioning as major ROS-scavenging sites. The functional analysis in the form of gene ontology newlineterms indicated that these genes are involved in mainly two biological processes (BP), viz., newlineoxidation reduction process (GO: 0055114) and cellular oxidant detoxification (GO: 0098869). newlineOxidoreductase (GO: 0016491) and antioxidant activity (GO: 0016209) are key molecular newlinefunction of these genes. Simultaneously, KEGG analysis shows that APX, DHAR, MDHAR, newlineand GR are directly linked to biosynthetic pathways of polyphenolic compounds (flavonoid, newlinetannin, and lignin). These genes are also involved in metabolism of glutathione (KEGG: 00480) newlineand; ascorbate and aldarate (KEGG: 00053). Whereas, SOD is indirectly linked to the same newlinepathways and also has antioxidant properties. Topological analysis of constructed networks of newlinethese genes in both genotypes of finger mi