title: Comparative analysis of drought-responsive transcriptome in Indica rice genotypes with contrasting drought tolerance.
abstract: Genetic improvement in drought tolerance in rice is the key to save water for sustainable agriculture. Drought tolerance is a complex trait and involves interplay of a vast array of genes. Several genotypes of rice have evolved features that impart tolerance to drought and other abiotic stresses. Comparative analysis of drought stress-responsive transcriptome between drought-tolerant (DT) landraces/genotypes and drought-sensitive modern rice cultivars will unravel novel genetic regulatory mechanisms involved in stress tolerance. Here, we report transcriptome analysis in a highly DT rice landrace, Nagina 22 (N22), versus a high-yielding but drought-susceptible rice variety IR64. Both genotypes exhibited a diverse global transcriptional response under normal and drought conditions. Gene ontology (GO) analysis suggested that drought tolerance of N22 was attributable to the enhanced expression of several enzyme-encoding genes. Drought susceptibility of IR64 was attributable to significant down-regulation of regulatory components that confer drought tolerance. Pathway analysis unravelled significant up-regulation of several components of carbon fixation, glycolysis/gluconeogenesis and flavonoid biosynthesis and down-regulation of starch and sucrose metabolism in both the cultivars under drought. However, significant up-regulation of α-linolenic acid metabolic pathway observed in N22 under drought appears to be in good agreement with high drought tolerance of this genotype. Consensus cis-motif profiling of drought-induced co-expressed genes led to the identification of novel cis-motifs. Taken together, the results of the comparative transcriptome analysis led to the identification of specific genotype-dependent genes responsible for drought tolerance in the rice landrace N22.
authors.affiliation: National Research Centre on Plant Biotechnology, Indian Agricultural Research Institute, New Delhi, India.
authors.forename: Sangram K
authors.initials: SK
authors.lastname: Lenka
authors.forename: Amit
authors.initials: A
authors.lastname: Katiyar
authors.forename: Viswanathan
authors.initials: V
authors.lastname: Chinnusamy
authors.forename: Kailash C
authors.initials: KC
authors.lastname: Bansal
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics*; D016000:Cluster Analysis; D016384:Consensus Sequence / Q000235:genetics; D055864:Droughts; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D005838:Genotype; D058977:Molecular Sequence Annotation; D012275:Oryza / Q000235:genetics* / Q000502:physiology*; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D015203:Reproducibility of Results; D014157:Transcription Factors / Q000235:genetics; D015854:Up-Regulation / Q000235:genetics; D017962:alpha-Linolenic Acid / Q000378:metabolism
chemical_list: D014157:Transcription Factors; D017962:alpha-Linolenic Acid