Oral Presentation International Plant Molecular Biology Conference 2024

Root-to-shoot, shoot-to-root translocation and symplasmic unloading of gibberellin detected by the Matryoshka GAMA3v-40n integrator. (#568)

Yuuma Ishikawa 1 , Khadija Rombi 1 , Ji-Yun Kim 1 2 , Tin Pau Pang 3 4 , Cheng Hsun Ho 5 , Dominik Spona 6 , Juan Barbosa Caro 1 , Marcel Dickmanns 1 , Alexander M Jones 7 , Masayoshi Nakamura 8 , Wolf B Frommer 1 8
  1. Heinrich Heine University Düsseldorf, Faculty of Mathematics and Natural Sciences, Institute for Molecular Physiology, Düsseldorf, Germany
  2. Sungkyunkwan University, Department of Biological Sciences, Suwon, South Korea
  3. Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University, Division of Cardiology, Pulmonology and Vascular Medicine, Düsseldorf, Germany
  4. Heinrich Heine University, Institute for Computer Science & Department of Biology, Düsseldorf, Germany
  5. Academia Sinica, Agricultural Biotechnology Research Center, Taipei 115, Taiwan
  6. Heinrich Heine University Düsseldorf, Institute for Functional Microbial Genomics, Düsseldorf, Germany
  7. University of Cambridge, Sainsbury Laboratory, Cambridge, UK
  8. Nagoya University, Institute for Transformative Biomolecules, ITbM, Nagoya, Japan

The phytohormone gibberellin (GA), a key contributing factor for the green revolution was discovered in the phytopathogenic Gibberella fujikuroi. GA causes bakanae after moving systemically from the fungus to rice internodes. To characterize GA transport, we developed the ultrasensitive Matryoshka-type GA integrator GAMA3v-40n. Using Arabidopsis expressing GAMA3v-40n, we detected GA4 root-to-shoot translocation, likely via the xylem, and subsequent spread in cotyledons, implicating the involvement of cellular transporter for xylem uptake in roots and apoplasmic uptake in shoot cells. When GA was applied to shoots, we detected shoot-to-root translocation and symplasmic unloading in root tips, likely from the phloem. We thus surmise that GA can move from root-to-shoot and shoot-to-root. Pathway analyses of single-cell gene expression data of GA-related genes and functional analyses of the presumed GA transporter AIT3/NPF leads us to predicting yet unknown GA transporters. Therefore, we screened candidates for new GA transporter using GAMA3v-40n expressing Arabidopsis. Here, we would like to show one new GA transporter, likely contributing to role for subcellular GA transport. GA translocation from leaf to shoot apical meristem presumably led to flowering transition, which GAMA3v-40n integrator is opening new vistas to visualize and test. Also, the molecules not only GA but also sugars likely could be translocated from leaf to shoot apical meristem, and we need to know the timing and translocation pattern of glucose and sucrose during the flowering transition with developing new sugar sensor. We thus have developed new ultrasensitive Matryoshka-type glucose or sucrose sensor and will show as new tools.