Miftahul Huda Fendiyanto 1,*, Mentari Putri Pratami 2, Elsa Gafira Cahyani1, Ifan Rizky Kurniyanto 3, Eko Setiawan 4, Fandri Sofiana Fastanti 2, Syatrianty A. Syaiful 5, Achmad Kautsar Baharuddin 6 and Muhammad Fuad Anshori 5,6*
1Department of Biology, Faculty of Military Mathematics and Natural Sciences, Indonesia Defense University, Kompleks Indonesia Peace and Security Center (IPSC) Kampus Universitas Pertahanan-Sentul, Bogor 16680, Indonesia; 2Research Center for Biosystematics and Evolution, National Research and Innovation Agency of Indonesia. Jl. Raya Jakarta-Bogor Km. 46, Cibinong, Bogor 16911, West Java, Indonesia; 3Department of Agricultural Science and Technology, Faculty of Agriculture, University of Trunojoyo Madura, Bangkalan 69162, Indonesia; 4Natural Resource Management Study Program, Faculty of Graduate, University of Trunojoyo Madura, Bangkalan 69162, Indonesia; 5Department of Agronomy, Hasanuddin University, Makassar, 90245, Indonesia; 6Rice Research Group, Faculty of Agriculture, Hasanuddin University, Makassar, 90245, Indonesia
*Corresponding author: fuad.anshori@unhas.ac.id (MFA), miftahul.fendiyanto@idu.ac.id (MHF)
Drought stress is a major constraint to rice (Oryza sativa L.) production, while mild PEG-6000-induced osmotic stress can be used under controlled conditions to simulate reduced water availability. Members of the Dehydration-Responsive Element-Binding (DREB) family play important roles in regulating plant responses to osmotic and drought-related stress. This study aimed to investigate DREB responses to mild PEG-6000-induced osmotic stress through public RNA-seq re-analysis and qRT-PCR analysis of the selected DREB gene in rice cultivars Inpago 6, Inpago 9, and IR64. Publicly available RNA-seq data from rice cv. Nipponbare were re-analyzed to identify drought-responsive genes, followed by independent qRT-PCR analysis of the selected DREB gene in rice cultivars Inpago 6, Inpago 9, and IR64. The RNA-Seq transcriptomic analysis revealed that members of the DREB gene family, particularly OsDREB2A, play important roles in rice drought response. In addition, we identified 1,793 upregulated and 1,793 downregulated genes, with a threshold of |log2 Fold Change |≥2 and an adjusted p-value (FDR) <0.05. Meanwhile, qRT-PCR showed that DREB4 expression under low drought stress was highest in Inpago 9 (250-fold), followed by IR64 (7.5-fold) and Inpago 6 (2.5-fold). These findings indicate that DREB4 plays an active role in drought tolerance under mild PEG-6000-induced osmotic stress and may serve as a candidate gene for developing drought-tolerant rice varieties, particularly Inpago 9.