The Wheat Code is Finally Cracked: Indian team contributed to sequencing of one of the 21 chromosomes
Shifting the limits in wheat research and breeding using a fully annotated reference genome (http://science.sciencemag.org/content/361/6403/eaar7191)
The International Wheat Genome Sequencing Consortium (IWGSC) published on Friday, 17th August 2018, in the international journal Science a detailed description of the genome of bread wheat, the world’s most widely cultivated crop. Sequencing the bread wheat genome was long considered an impossible task, due to its enormous size – five times larger than the human genome and 40 times larger than rice genome – and complexity – bread wheat has three sub-genomes and more than 85% of the genome is composed of repeated elements. The high quality reference genome will pave the way for development of wheat varieties with higher yields, enhanced nutritional quality, improved sustainability and better adapted to climate challenges.
The research article – authored by more than 200 scientists from 73 research institutions in 20 countries – presents the reference genome of the bread wheat variety Chinese Spring. A team of 18 Indian scientists co-authoring this paper led by Dr. Kuldeep Singh at Punjab Agricultural University Ludhiana (Now Director, ICAR-National Bureau of Plant Genetic Resources), Professor Nagendra Singh at ICAR-National Research Centre on Plant Biotechnology, New Delhi and Professor JP Khurana at the University of Delhi South Campus, contributed to the decoding of Chromosome 2A of the wheat genome. This project was financially supported and its progress monitored by the Department of Biotechnology, Government of India. The DNA sequence ordered along the 21 wheat chromosomes is the highest quality genome sequence produced to-date for wheat. It is the result of 13 years of collaborative international research.
A key crop for food security, wheat is the staple food of more than a third of the global human population and accounts for almost 20% of the total calories and protein consumed by humans worldwide. To meet future demands of a projected world population of 9.6 billion by 2050, wheat productivity needs to increase by 1.6 per cent each year. For India especially, in order to preserve biodiversity, water, and nutrient resources, the majority of this increase has to be achieved via crop and trait improvement on land currently cultivated rather than committing new land to cultivation.
With the reference genome sequence now completed, breeders have at their disposal new tools to address these challenges. They will be able to identify more rapidly genes and regulatory elements underlying complex agronomic traits such as yield, grain quality, resistance to fungal diseases, and tolerance to abiotic stress – and produce hardier wheat varieties..
The publication of the wheat reference genome is the culmination of the work of many individuals who came together under the banner of the IWGSC in 2006 and India joining the consortium in 2008 was spearheaded by Kellye Eversole, Executive Director IWGSC, to do what was once considered impossible. The method of producing the reference sequence and the principles and policies of the consortium provide a model for sequencing large, complex plant genomes and reaffirms the importance of international collaborations for advancing science and achieving food security. The draft sequence of wheat was published by IWGSC in 2014 and made available to wheat breeders and researchers for use, however, the present version is the most accurate and complete. The impact of the wheat reference sequence has already been significant in the scientific community, as exemplified with more than 100 publications using reference genome, since the resource was made available to the scientific community in January 2017. Almost all the wheat breeding groups in India are already using the genomics resources generated from this collaborative work, from the reference sequence for marker assisted selection.
In addition to the DNA sequence of the 21 chromosomes, the Science article also presents the precise location of 107,891 genes and of more than 4 million molecular markers, as well as sequence information between the genes and markers containing the regulatory elements influencing the expression of genes.
The IWGSC achieved this result by combining the genomics resources it developed over the last 13 years, using classic physical mapping methods and the most recent DNA sequencing technologies and highly efficient algorithms. The 107,891 genes were identified with dedicated software programmes. All IWGSC reference sequence resources are publicly available at the IWGSC data repository at URGI-INRA Versailles and at other international scientific databases such as GrainGenes and Ensembl Plant.
(Source: Dr. Kuldeep Singh, Director, ICAR-NBPGR, New Delhi)