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ORIGINAL RESEARCH article

Front. Plant Sci.
Sec. Functional and Applied Plant Genomics
Volume 15 - 2024 | doi: 10.3389/fpls.2024.1451215

UV-Induced Reactive Oxygen Species and Transcriptional Control of 3-Deoxyanthocyanidin Biosynthesis in Black Sorghum Pericarp

Provisionally accepted
Brooklyn Schumaker Brooklyn Schumaker 1Lauren Mortensen Lauren Mortensen 1Robert R. Klein Robert R. Klein 2Sabyasachi Mandal Sabyasachi Mandal 3Linda Dykes Linda Dykes 4Nicholas Gladman Nicholas Gladman 5,6William L. Rooney William L. Rooney 7Byron Burson Byron Burson 2Patricia E. Klein Patricia E. Klein 1*
  • 1 Department of Horticultural Sciences, College of Agriculture and Life Sciences, Texas A&M University College Station, College Station, Texas, United States
  • 2 Southern Plains Agricultural Research Center, Agricultural Research Service (USDA), College Station, Texas, United States
  • 3 Department of Biological Sciences, College of Arts & Sciences, Texas Tech University, Lubbock, United States
  • 4 Edward T. Schafer Agricultural Research Center, Agricultural Research Service (USDA), Fargo, North Dakota, United States
  • 5 Robert W. Holley Center for Agriculture and Health, Agricultural Research Service (USDA), Ithaca, New York, United States
  • 6 Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, United States
  • 7 Department of Soil & Crop Sciences, College of Agriculture and Life Sciences, Texas A&M University College Station, College Station, Texas, United States

The final, formatted version of the article will be published soon.

    Black pericarp sorghum has notable value due to the biosynthesis of 3-deoxyanthocyanidins (3-DOAs), a rare class of bioactive polyphenols valued as antioxidant food additives and as bioactive compounds with cytotoxicity to human cancer cells. In this study, a metabolic and transcriptomic study was conducted to ascertain the cellular events leading to the activation of 3-DOA biosynthesis in black sorghum pericarp. Prolonged exposure of pericarp during grain maturation to high-fluence ultraviolet (UV) light resulted in elevated levels of reactive oxygen species (ROS) and the activation of 3-DOA biosynthesis in pericarp tissues. Associated with 3-DOA biosynthesis was the transcriptional activation of specific family members of early and late flavonoid biosynthesis pathway genes. A working model of UV-induced 3-DOA biosynthesis in black pericarp is proposed that shares features of plant immunity associated with pathogen attack or mechanical wounding. The present model depicts ROS biosynthesis, the transcriptional activation of receptor kinases and transcription factors (TFs) including NAC, WRKY, bHLH, AP2, and C2H2 Zinc finger domain. Associated with these cellular events was the downstream activation of defense-related pathways and the biosynthesis of secondary metabolites including 3-DOAs. Promoter analysis of genes highly correlated with 3-DOA biosynthesis in black pericarp were enriched in MYB and HHO5/ARR-B motifs. Light microscopy studies of black pericarp tissues suggest that 3-DOAs are predominantly localized in the epicarp and are associated with the cell wall.

    Keywords: 3-Deoxyanthocyanidin1, sorghum2, Pericarp3, Transcriptomics4, Gene Co-Expression Network5, UV light6, ROS7

    Received: 18 Jun 2024; Accepted: 10 Sep 2024.

    Copyright: © 2024 Schumaker, Mortensen, Klein, Mandal, Dykes, Gladman, Rooney, Burson and Klein. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Patricia E. Klein, Department of Horticultural Sciences, College of Agriculture and Life Sciences, Texas A&M University College Station, College Station, Texas, United States

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