Indian scientists along with their international partners — International Wheat Genome Sequencing Consortium (IWGSC) — have managed to crack the genetic code of bread wheat. They have prepared a blueprint of the wheat genome sequencing which can help scientists to now prepare new varieties of wheat having higher yield and better grain quality besides being pest resistant.
Wheat was considered one of the toughest crops to decode due to its huge genome size of 17000 million base pairs, and presence of three sets of highly similar chromosomes in the genome and a very large proportion of repetitive DNA. For each gene in wheat there are three copies, one from each of the three genomes, and in most cases only one copy expresses. How the plant decides which copy of the gene to express remains a mystery for wheat biology. But availability of chromosome based sequence has now opened new horizons for researching this issue, said the research paper published in US journal Science.
The decoding of wheat genome has helped in identifying more than 125,000 genes and almost 50 per cent of these assigned these to the individual wheat chromosomes. This has opened gates for understanding the biological function of each of these genes. The current draft sequence has generated thousands of DNA markers which could be used as ‘tag’ for identification of any gene in wheat and its subsequent transfer to any variety through cross hybridization much precisely and rapidly.
India’s three leading institutes — Punjab Agricultural University (ludhiana), National Research Centre on Plant Biotechnology (New Delhi), and South Campus Delhi University (New Delhi, with support from Department of Biotechnology (DBT), Government of India — were entrusted with the responsibility of decoding one chromosome, designated as 2A, which is about 900 million bases in size and is about one third the size of the human genome or 2.5 times the size of rice genome.
“Taking forward with molecular breeding and genetic engineering we would be able to develop climate smart wheat (drought/terminal heat tolerance) with higher yield. 22,000 wheat germplasm has been evaluated by NBPGR/ICAR. We would be able to use our germplasm better now with this science-discovery,” said Dr Swapan Datta, Deputy Director General (Crop Sciences) at Indian Council of Agricultural Research.
Wheat is a major dietary component for many countries across the world due to high carbohydrate and protein content. Grown on more land than any other crop, more than 215 million hectares of wheat are harvested annually to generate a world production of almost 700 million tons, making it the third most produced cereal after maize and rice. It is the leading source of vegetable protein in human food, having higher protein content than either maize or rice.
The wheat plant is highly versatile due to its ability to grow in a wide range of environments. Also, wheat grain can easily be stored and can be converted readily into flour for making numerous varieties of high quality edible food. The goal of the IWGSC is to make a high quality genome sequence of bread wheat publicly available, in order to lay a foundation for basic research that will enable breeders to develop improved varieties.