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Open Access Highly Accessed Research article

SNPs in stress-responsive rice genes: validation, genotyping, functional relevance and population structure

Swarup K Parida1, Mitali Mukerji2, Ashok K Singh3, Nagendra K Singh1 and Trilochan Mohapatra14*

  • * Corresponding author: Trilochan Mohapatra tm@nrcpb.org

  • † Equal contributors

Author affiliations

1 National Research Centre on Plant Biotechnology, Indian Agricultural Research Institute, New Delhi, 110012, India

2 Institute of Genomics and Integrative Biology, Delhi, 110007, India

3 Division of Genetics, Indian Agricultural Research Institute, New Delhi, 110012, India

4 Present Address: Central Rice Research Institute, Cuttack, 753 006, Odisha, India

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Citation and License

BMC Genomics 2012, 13:426  doi:10.1186/1471-2164-13-426

Published: 25 August 2012

Abstract

Background

Single nucleotide polymorphism (SNP) validation and large-scale genotyping are required to maximize the use of DNA sequence variation and determine the functional relevance of candidate genes for complex stress tolerance traits through genetic association in rice. We used the bead array platform-based Illumina GoldenGate assay to validate and genotype SNPs in a select set of stress-responsive genes to understand their functional relevance and study the population structure in rice.

Results

Of the 384 putative SNPs assayed, we successfully validated and genotyped 362 (94.3%). Of these 325 (84.6%) showed polymorphism among the 91 rice genotypes examined. Physical distribution, degree of allele sharing, admixtures and introgression, and amino acid replacement of SNPs in 263 abiotic and 62 biotic stress-responsive genes provided clues for identification and targeted mapping of trait-associated genomic regions. We assessed the functional and adaptive significance of validated SNPs in a set of contrasting drought tolerant upland and sensitive lowland rice genotypes by correlating their allelic variation with amino acid sequence alterations in catalytic domains and three-dimensional secondary protein structure encoded by stress-responsive genes. We found a strong genetic association among SNPs in the nine stress-responsive genes with upland and lowland ecological adaptation. Higher nucleotide diversity was observed in indica accessions compared with other rice sub-populations based on different population genetic parameters. The inferred ancestry of 16% among rice genotypes was derived from admixed populations with the maximum between upland aus and wild Oryza species.

Conclusions

SNPs validated in biotic and abiotic stress-responsive rice genes can be used in association analyses to identify candidate genes and develop functional markers for stress tolerance in rice.

Keywords:
Illumina GoldenGate assay; Population structure; Rice; SNPs; Single nucleotide polymorphisms; Stress-responsive genes