Precision genetic technologies for cereal functional genomics

Abstract

Identifying and characterizing genes that control important agronomic traits and finding ways to alter them are vital for crop improvement. Map-based cloning, heterologous gene expression, RNAi mediated gene silencing, T-DNA insertional mutation and TILLING technologies have enabled cloning, characterization, and deployment of a few important genes. Revolution in sequencing technologies and bioinformatics has facilitated us to quickly predict and annotate plethora of genes and regulatory elements with improved precision and spatio-temporal expression of genes in almost all cereal crops. However, their functional validation forms a bottleneck in exploiting useful genetic elements for crop improvement. The CRISPR/Cas9 mediated gene editing has become the tool of choice for precisely introducing targeted modifications in the genome to knock out/in a gene, introducing specific mutation in sequence or modulating its expression in diverse crop species. This can help to rapidly characterize plenty of genes in terms of understanding the function of individual gene/ gene family, involvement in a particular biochemical pathway or interaction of the crop plant with external stimuli at a reasonable cost. In this review, we discuss the power of gene editing for rapid functional characterization of genetic elements as a fundamental requirement to harness the power of precision genetic technologies for increasing crop yield, progress made so far, opportunities and challenges.