Recent Advances in Sequencing of Cereal Genomes

Abstract

AbstractCereal crops are members of the Poaceae family that are grown primarily for their seed, many of which are staple foods around the globe. Together, maize, rice, wheat, barley, sorghum, millet, oat, rye, and triticale make up more than half of the agricultural production globally. Since diverging from a common ancestor 50–70 Mya, the genomes of cereal crops have been subject to evolutionary forces giving rise to changes in genome size, composition, and complexity. Over the past two decades, efforts to sequence the genomes of the main cereal crops have resulted in highly contiguous, chromosome-scale genome assemblies. Rice has the smallest genome size (420 megabases (Mb)), which led to it being the first assembled cereal genome. However, the immense genome size and complexity for some cereal crops, such as wheat (17 gigabases (Gb)) and oat (12 Gb), have hindered genome sequencing progress. Recently, the reduction in sequencing costs coupled with new technological advances including ultra-long-read sequencing and advanced genome assembly algorithms has now made it possible to achieve chromosome-scale assemblies in all cereals. As a result, we have now entered a new era of genomics for cereal crops. Researchers now face the daunting task of unravelling the function of all genes and non-genic regions of the genomes in cereals, particularly in crops like wheat and oat where little is known about the genetic basis for most economically important traits. Recent advances in high-throughput phenotyping, metabolomics, proteomics, and CRISPR/CAS9 technologies will facilitate this process and pave the way for exciting discoveries in functional genomics of cereals.Key wordsSequencingGenomicsCerealsPan-genomeFunctional genomics