Role of Reactive Oxygen Species During Maize Kernel Development
Research Poster Health & Life Sciences 2025 Graduate ExhibitionPresentation by Gurkirat Singh
Exhibition Number 84
Abstract
Reactive oxygen species (ROS) are oxygen derivatives that function as signaling molecules in plant growth and development, however, excessive levels can cause oxidative stress, leading to cellular damage. Maize unstable factor for orange1 (Zmufo1) is expressed during basal endosperm transfer layer (BETL) differentiation, which facilitates nutrient transport in the developing kernel. At 10 days after pollination (DAP), previous research using mutant alleles of Zmufo1, i.e., Ufo1-1 expresser (UE) and loss of function (ufo1-Dsg), has associated abnormal ROS accumulation with BETL defects, oxidative DNA damage, and cell death. The objective of this study was to investigate ROS accumulation changes during the basal endosperm transfer cells (BETC) formation and differentiation stage across different Zmufo1 genotypes: overexpressing Ubipro:ufo1 transgenic (Tg+UE), transgene-absent (Tg), ufo1-Dsg, and wildtype W22. Longitudinally dissected kernels at 4 and 8 DAP were stained with superoxide-sensitive nitroblue tetrazolium chloride (NBT) and hydrogen peroxide (H2O2) sensitive 3,3’-diaminobenzidine (DAB). Additionally, hydrogen peroxide levels were quantified spectrophotometrically using potassium iodide (KI). Stronger NBT and DAB staining was observed in Tg+UE kernels compared to other genotypes. Spectrophotometric results revealed elevated H2O2 levels in Tg+UE kernels, whereas Tg-, ufo1-Dsg, and W22 had lower H2O2 accumulation at both 4 and 8 DAP stages. These preliminary findings provide evidence that Zmufo1 influences ROS homeostasis during BETC formation and differentiation, ultimately affecting maize seed development. The ongoing research will also investigate the effect of changes in ROS, DNA methylation, and gene expression regulated through the Zmufo1 pathway. This project is supported by the National Science Foundation award 2341575.
Importance
Maize (corn) is a key source of food, feed, biofuel, and various food products. Maize kernel is a commodity because of the endosperm, a storage reservoir for sugars, starch, and proteins. Photosynthates synthesized in leaves are transported to the kernel endosperm via specialized cell layers, including the basal endosperm transfer layer (BETL), which has a critical role in nutrient transport. The Zmufo1 gene is specifically expressed during BETL development, and its mutations have abnormal accumulation of redox and sugars, transcriptional alterations, and defective BETL cells. By using different Zmufo1 mutations and genetic lines, this study aims to understand the function of ROS-mediated changes in gene expression and cellular development, providing insights into nutrient transport mechanisms in maize kernels.