Kyaw (Joe) Aung
Date & Time: November 4, 2024, at 4 pm
Location: BCH 101
Zoom: https://msu.zoom.us/j/91993518218?pwd=SzN0Umd0dElSblVSOGJEY2U0UzJJdz09
Meeting ID: 919 9351 8218
Passcode: 028299
Host: Jianping Hu
About the Speaker
Institution: Iowa State University
Subject: Regulation of cell-to-cell communication during plant growth and defense
Abstract: A hallmark of multicellular organisms is their ability to maintain physiological homeostasis through communication among cells, tissues, and organs. In plants, this intercellular communication largely depends on plasmodesmata, membrane-lined channels that connect adjacent plant cells. The plant polysaccharide callose is deposited at plasmodesmata, regulating their aperture and function. Among the proteins that maintain callose homeostasis, PLASMODESMATA-LOCATED PROTEINS (PDLPs) promote callose deposition at plasmodesmata. To determine the molecular function of PDLPs, we performed an enzyme-catalyzed proximity labeling assay to identify their functional partners. We identified SUCROSE SYNTHASE 6 (SUS6), which is involved in callose biosynthesis, as a cell type-specific functional partner of PDLP6. We further demonstrated that PDLP6, SUS6, and CALLOSE SYNTHASE 7 (CALS7) work together to regulate plasmodesmal function, specifically in the vasculature. These findings reveal the cell type-specific regulation of plasmodesmata by PDLP6 and its role in plant growth. Additionally, we identified proteins involved in reactive oxygen species (ROS) production, sensing, and transportation as potential functional partners of PDLP5. Given the importance of ROS signaling and PDLP5 in plant immunity, we test the hypothesis that PDLP5 and plasmodesmata function as ROS signaling hubs. Our studies showed that PDLP5 physically interacts with PLASMA MEMBRANE INTRINSIC PROTEINs (PIPs), which transport water and hydrogen peroxide. In line with AlphaFold-Multimer's prediction of PDLP5-PIP heterocomplexes, our results indicated that PDLP5 negatively regulates hydrogen peroxide transport, likely by blocking the PIP channels. Our studies begin to uncover the cell type-specific function of PDLPs and the novel role of PDLP5 in regulating plant cell-to-cell communication.