The first draft sequence of the cotton genome,a compilation of all the basic DNA sequences of one of the largest and most difficult-to-decode genomes in the plant kingdom,has been unveiled in a paper by a team led by Andrew H Paterson,University of Georgia,and published in Nature. The team has identified several genes in the cotton genome that resist diseases and insect pests,apart from those that relate to fibre quality. The findings allow the researchers to discover how the fibre-producing plant has evolved over a period of several million years from wild form to the currently domesticated species,and offer possibilities of tackling diseases and improving production and quality of the fibre. The paper was published by an international consortium of 74 scientists from 31 institutions across 11 countries,including the Central Institute for Cotton Research (CICR) in Nagpur. CICR principal scientist Vijay Waghmare was involved in the genome sequencing research along with Paterson as visiting scientist and post-doctoral fellow for two years. More than 90 per cent of cotton cultivated in India and across the world contains what is called the AD genome. A genome belongs to Indian cotton,D genome to American cotton,and the two had cross-bred millions of years ago. The team presented a high-quality draft assembly of the smallest cotton D genome sequence from the wild species Gossypium raimondii,from which all cultivable cotton varieties have evolved. The work is a significant advance in cotton research,especially considering the huge size of the cotton genome, says Keshav Kranthi,CICR director. The study found G raimondii is among the most complex of flowering plant genomes. The researchers compared its genome sequence to several other sets of cotton data provided by the US Department of Agriculture. This study reveals evolutionary processes salient to all plants and provides a strategy to better understand the genome of many other crops,such as canola,wheat and peanut, Paterson said. The study will help expedite the development of robust and innovative cotton varieties to increase yields,fibre quality,and can help optimise the use of inputs and,thus,contribute to reducing environmental impact of growing cotton. Dr Don Jones,director of Agricultural Research at Cotton Incorporated,said,This sequence is a cornerstone that will help advance our knowledge so we more thoroughly understand the biology that leads to enhanced yield,improved fibre quality,and better stress tolerance,all improvements that will benefit growers in the not-too-distant future. The cotton genome sequence data has been made freely available in the public domain with open access and researchers across the continent can use the data in their research to improve sustainability of cotton production, says Waghmare. These molecular data can be used for marker-assisted substance plant breeding (selecting particular trait) programmes in a very precise manner. CICR has already started such a programme this year on developing pest and disease-resistant varieties. We are validating the molecular markers for resistance to major diseases such as the leaf-curl virus and bacterial blight and plant parasitic nematodes using the sequence data, Kranthi said.
