biostudies-arrayexpressGladys Iliana CassabZea mayshttps://www.ebi.ac.uk/biostudies/studies/E-MTAB-16240The subsistence of terrestrial plants depends upon the ability of roots to absorb water and nutrients from the soil. Directed growth of the primary root from a layer of the soil with low water content towards a zone with high water content is known as hydrotropism. This tropic response enables the root to reach soil with the proper humidity for plant growth, and therefore avoid drought conditions. Although the shortage of sufficient water is the single-most critical factor affecting world agriculture, there are very few studies on hydrotropism in crop plants. The strength of the hydrotropic response (angle of curvature) of the maize primary root in maize varies enormously. After phenotyping root hydrotropism in 231 Drought Tolerant Maize for Africa hybrids, we performed a Genome Wide Association Study and found two candidate genes that regulate the ubiquitin/26 proteasome system. We also compared the root transcriptomes between maize accessions with contrasting hydrotropic response after 6 h of hydro stimulation: (CML376<2/NVOL46)-74-1-1-B) (robust response) and (CML376<2/SNL17)-28-1-1-B) (weak response). This analysis revealed that hydrotropism in maize seems to be regulated by chaperones, heat shock proteins, late embryogenesis abundant proteins, and ubiquitin ligases. Furthermore, we biochemically examined the role of protein ubiquitination and protein degradation during hydrotropism. Our results suggest that the signal transduction pathways induced by hydro stimulation in maize are like those triggered by heat, water stress, and protein ubiquitination.biostudies-arrayexpressGrowth Protocol - Maize seeds were disinfected and germinated on sterilized trays with wet paper towels at 28°C in darkness. Seedlings with primary roots reaching 2–3 cm length (3–4-day post-germination) were utilized to test their root hydrotropic response.Sample Treatment - The hydrotropic assay was made in a transparent acrylic box with a lid with two hydro stimulants fitted inside the two lateral walls of the box, and a hygroscopic solution placed on the bottom. The hydro stimulant is a piece of green floral foam (Oasis®; 10 cm in height, 7 cm in width, 3 cm in depth) that was enfolded with a piece of craft paper to protect roots from abrasion whilst affixing. The filter paper and the floral foam were saturated for 10 min with distilled water. Selected seedlings (with roots of 2–3 cm length) were mounted on the hydro stimulant by attaching the seedlings with the help of pins placing the root with a downward direction and adjusting the tip-end of the root nearly 1 mm down the edge of the wrapped floral-foam. For hydro stimulation, 200 mL of a saturated solution of K2CO3 (Sigma-Aldrich) with a density of 1.50 g/cm were poured carefully into the box after setting the hydro stimulants with seedlings mounted on it. The vertical distance between the edge of each hydro stimulant and the surface level of the solution was maintained at 6 cm. For control experiments (gravistimulation), 400 mL of distilled water were dispensed in the box instead of the saturated solution of K2CO3. Two pieces of floral foam, each enclosing 2 seedlings, were placed in the box (20 cm in height, 25 cm in width, 10 cm in depth) for each experiment.Library Construction - TruSeq Stranded mRNA Sample Prep Kit IlluminaSequencing - RNA sequencing was conducted on an Illumina HiSeq PlatformNucleic Acid Extraction - We made a comparative transcriptomic analysis between a maize hybrid with robust HR (CML376<2/NVOL46)-74-1-1-B) (curvature angle: 44.4° + 20.1° SD) versus an accession with a weak HR (CML376<2/SNL17)-28-1-1-B) (curvature angle: 13.55° + 8.35° SD). Both hybrid accessions were a gift form Dr. Terence Molnar from CIMMYT (Texcoco, Mexico). We collected root tissue from two experimental conditions in the hydrotropism assay system: one with a moisture gradient generated by K2CO3 and another without a moisture gradient and in the presence of H2O (control). Roots from maize seedlings with robust HR or weak HR were sampled and immediately frozen with liquid nitrogen at 0 and 6 h for transcriptome sequencing experiments. Three biological replicates of the two experimental conditions and from each of the two different maize hybrids, were used. Total RNA was extracted from the samples using TRIzol reagent (Invitrogen) according to the manufacturer’s instructions, and RNA sequencing was conducted on an Illumina HiSeq platform.Sample Collection - Maize seeds were disinfected and germinated on sterilized trays with wet paper towels at 28°C in darkness. Seedlings with primary roots reaching 2–3 cm length (3–4 days post-germination) were utilized to test their root hydrotropic response.OrganizationMINSEQE ScoreAssays and DataMAGE-TAB FilesData Transformation - NAMetabolomicsUnknownTranscriptomicsGenomicsProteomicsIllumina HiSeq 2000RNA-seq of coding RNAZea maysGladys Iliana CassabfalseGenome Wide Association Study, transcriptome and biochemical analyses provide insights into the root hydrotropic response of maize (Zea mays L.).The subsistence of terrestrial plants depends upon the ability of roots to absorb water and nutrients from the soil. Directed growth of the primary root from a layer of the soil with low water content towards a zone with high water content is known as hydrotropism. This tropic response enables the root to reach soil with the proper humidity for plant growth, and therefore avoid drought conditions. Although the shortage of sufficient water is the single-most critical factor affecting world agriculture, there are very few studies on hydrotropism in crop plants. The strength of the hydrotropic response (angle of curvature) of the maize primary root in maize varies enormously. After phenotyping root hydrotropism in 231 Drought Tolerant Maize for Africa hybrids, we performed a Genome Wide Association Study and found two candidate genes that regulate the ubiquitin/26 proteasome system. We also compared the root transcriptomes between maize accessions with contrasting hydrotropic response after 6 h of hydro stimulation: (CML376<2/NVOL46)-74-1-1-B) (robust response) and (CML376<2/SNL17)-28-1-1-B) (weak response). This analysis revealed that hydrotropism in maize seems to be regulated by chaperones, heat shock proteins, late embryogenesis abundant proteins, and ubiquitin ligases. Furthermore, we biochemically examined the role of protein ubiquitination and protein degradation during hydrotropism. Our results suggest that the signal transduction pathways induced by hydro stimulation in maize are like those triggered by heat, water stress, and protein ubiquitination.2026-06-30T00:00:00Z2026-06-30T01:01:13.146Z2025-11-21T10:09:38.677ZE-MTAB-16240ERP185459EFO_0002944EFO_0004170EFO_0003789EFO_0005518EFO_0003816EFO_0003738EFO_0004184EFO_0003969