Transcriptome and Physio-Biochemical Profiling Reveals Differential Responses of Rice Cultivars at Reproductive-Stage Drought Stress

• Published in: International journal of molecular sciences Vol. 24; no. 2; p. 1002
• Main Authors: Kaur, Simardeep, Seem, Karishma, Duhan, Naveen, Kumar, Suresh, Kaundal, Rakesh, Mohapatra, Trilochan
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 05.01.2023; MDPI
• Subjects: Adaptability; Comparative analysis; Cultivars; Dehydration; Drought; Drought resistance; drought stress; Droughts; Edible Grain - genetics; Gene expression; Gene Expression Profiling; Gene Expression Regulation, Plant; Genes; Homeostasis; Linoleic acid; MapMan; Metabolites; Oryza - metabolism; Phenylalanine; Plant growth; Reproduction; reproductive-stage drought; Rice; Secondary metabolites; Seeds; Signal transduction; Stress, Physiological - genetics; Sucrose; Transcription factors; Transcription Factors - metabolism; Transcriptome; transcriptome analysis; Transcriptomes; Water shortages; drought stress; reproductive-stage drought; transcriptome analysis; rice; transcription factors; MapMan
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms24021002

Drought stress severely affects the growth and development of rice, especially at the reproductive stage, which results in disturbed metabolic processes, reduced seed-set/grain filling, deteriorated grain quality, declined productivity, and lower yield. Despite the recent advances in understanding the responses of rice to drought stress, there is a need to comprehensively integrate the morpho-physio-biochemical studies with the molecular responses/differential expression of genes and decipher the underlying pathways that regulate the adaptability of rice at various drought-sensitive growth stages. Our comparative analysis of immature panicle from a drought-tolerant (Nagina 22) and a drought-sensitive (IR 64) rice cultivar grown under control (well-watered) and water-deficit/drought stress (treatment, imposed at the reproductive stage) conditions unraveled some novel stress-responsive genes/pathways responsible for reproductive-stage drought stress tolerance. The results revealed a more important role of upregulated (6706) genes in the panicle of N 22 at reproductive-stage drought stress compared to that (5590) in IR 64. Functional enrichment and MapMan analyses revealed that majority of the DEGs were associated with the phytohormone, redox signalling/homeostasis, secondary metabolite, and transcription factor-mediated mitigation of the adverse effects of drought stress in N 22. The upregulated expression of the genes associated with starch/sucrose metabolism, secondary metabolites synthesis, transcription factors, glutathione, linoleic acid, and phenylalanine metabolism in N 22 was significantly more than that in the panicle of IR 64. Compared to IR 64, 2743 genes were upregulated in N 22 under control conditions, which further increased (4666) under drought stress in panicle of the tolerant cultivar. Interestingly, we observed 6706 genes to be upregulated in the panicle of N 22 over IR 64 under drought and 5814 genes get downregulated in the panicle of N 22 over IR 64 under the stress. In addition, RT-qPCR analysis confirmed differential expression patterns of the DEGs. These genes/pathways associated with the reproductive-stage drought tolerance might provide an important source of molecular markers for genetic manipulation of rice for enhanced drought tolerance.