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Plant genomics
and agriculture: From model organisms to crops, the role of data
mining for gene discovery
Viswanathan
Mahalakshmi Rodomiro
Ortiz* * Corresponding
author Keywords: bio-informatics,
DNA linkage maps, genetic markers, plant breeding.
The complete sequencing of the Arabidopsis thaliana genome has been regarded as a landmark in plant sciences. Over the last two decades, comparative genetics has shown that the organization of genes within plant genomes has remained conserved over the evolutionary periods. The sequencing of the genome of a model species is just the beginning of a new venture to unravel genetic information and to gain better insight into the genetics of other species under investigation. However, a question should be posed: What is the co-linearity between model plant systems, which are receiving priority attention for DNA sequencing, and more important crop species belonging to the same taxon? Insights from the Arabidopsis sequence, which has one copy of each gene and less than 10% repetitive DNA sequences, are likely to boost developments in agricultural science, but the bigger challenge today is to use this information and to extend it to food, feed and fiber crops. Rice, one of the most important crops in the tropics, is the next model plant system receiving priority attention for genome sequencing. The argument on whether other agricultural crops need complete genome sequencing or the information from these model crops receiving sequencing attention will be sufficient will continue. Though eventually as the cost declines and the process of sequencing gets more automated, all food and commercially important crops may get fully sequenced. However, the agricultural research community need not wait to reap the benefit as they can make better-informed decisions based on current knowledge from the model crops. This article discusses how this can be achieved using our work on sorghum as an example, which benefited from the rice genome initiative. Construction of a linkage map is fundamental step for a detailed genetic study and marker-assisted breeding approach in any crop. Sorghum genome mapping based on DNA markers began in 1990s, and since then several maps have been published. An interactive web based consensus map of all published maps of sorghum (11 in 2000) was developed. The strong co-linearity between grass species suggests synteny between the grasses. The web-based interactive comparative maps of rice and sorghum suggest an extensive conservation of gene order between rice and sorghum genomes. The practical aspects of this information would be in map-based cloning for specific genes. As the functional information in rice gets accumulated the same would be an important resource for researchers to develop trait-based markers especially expressed sequence tag (EST). This article also highlights the benefits for sharing information in the public domain and the role of bioinformatics. Today, the search for a gene of interest starts with sequence information, including EST, genome sequence and protein sequence. This information is publicly available for large- scale analysis from GenBank at the National Center for Biotechnology Information (NCBI) and European Molecular Biology Laboratory (EMBL). Genome related public databases have already become an invaluable part of the scientific community and are the public window for the high-throughput genomic projects. The thrust of a high-throughput facility is the creation of large, well-organized, rigorous datasets. Public domain databases, most notably the model organism databases, have two major consumers: the focused scientific community actively studying that system, and the large scientific community interested in relating this specialized information to and from other systems. As mentioned earlier, model system databases would be increasingly mined by others but related crop specialists to design markers for marker-assisted selection and -aided introgression methods. Finding new genes that add value to agricultural crops and their products has immense value in agri-business. For rice genome sequence data, scientists are leveraging on data from other model crops for gene annotation. This process of data mining will continue and intensify for the benefit of other crop species. |
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