Functional Characterization of Expressed Sequence Tags of Bread Wheat (Triticum aestivum) and Analysis of CRISPR Binding Sites for Targeted Genome Editing

摘要

Bread wheat (Triticum aestivum) is one of the leading food crop worldwide. However, functional characterization of wheat genome is still under progress due to its huge size (~17 Gb). We aimed to contribute in this project by functional characterization EST sequences. Wheat EST sequences (1.2 million available in the EST database) were cleaned and assembled into 27268 contigs at stringent parameters. About 89% (24339) contigs were functionally annotated using BlastX search at NCBI-NR protein database with 10^-5 e-value. The annotated contigs were further classified into Gene Ontology terms and mapped for KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway using Blast2GO program. A total of 78827 GO terms and 132 KEGG pathways were identified. Purine, and starch and sucrose metabolism were major pathways. Inositol phosphate metabolism pathway, responsible for the synthesis of phytic acid (an anti-nutritional component), was also significantly represented in wheat. We identified 3327 EST-SSRs in 2832 contigs and probable CRISPR binding sites in each contigs. Further, a hypothetical phytic acid biosynthetic pathway and possible important target genes to reduce the phytic acid content in wheat by CRISPR-Cas system has also been described. Our study provides the genetic information about an important food crop as well as method for nutritional improvement using a modern biotechnology tool.