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Abstract

Drought stress represents a critical constraint to rice productivity worldwide, necessitating a comprehensive understanding of the molecular mechanisms underlying stress tolerance. This study employed RNA sequencing to investigate drought-responsive transcriptional networks in root tissues of two contrasting rice genotypes: Azucena (drought-tolerant) and IR64 (drought-sensitive). Twenty-day-old seedlings were subjected to 14-day drought stress treatment, and transcriptomic profiles were analyzed using high-throughput sequencing. Quality-filtered reads achieved >95% Q30 scores with alignment rates of 94.48–96.55% to the reference genome. Differential expression analysis identified 30,419–31,052 differentially expressed genes across four comparison groups, with the drought-sensitive IR64 exhibiting approximately 15% more differentially expressed genes (DEGs) than the drought-tolerant Azucena. Venn diagram analysis revealed 1,635 shared DEGs representing core drought response mechanisms, 524 Azucena-specific DEGs, and 1,052 IR64-specific DEGs. Gene Ontology enrichment analysis highlighted significant involvement of stress response, hormone signaling, and metabolic regulation pathways. While KEGG pathway analysis demonstrated that IR64 activated glutathione metabolism and diterpenoid biosynthesis pathways, Azucena preferentially upregulated energy metabolism pathways, including starch/sucrose metabolism and glycolysis. Transcription factor profiling identified 29–153 differentially expressed transcription factors across comparisons, with Azucena showing selective activation of NAC and WRKY families associated with ABA-dependent stress responses, whereas IR64 exhibited broader activation of bHLH and MYB families. Key signaling components, including the plasma membrane H+-ATPase and ABA-responsive element binding factors, were significantly upregulated under drought conditions. Collectively, these results provide mechanistic insight into genotype-specific molecular strategies that underpin drought tolerance in rice. Also, delineate promising candidate genes for marker-assisted selection and genetic engineering aimed at improving drought resilience in cereal crops.

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189

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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