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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Plant Sci. | doi: 10.3389/fpls.2019.01202

Negative regulation of age-related developmental leaf senescence by the IAOx pathway, PEN1 and PEN3

 Judy Brusslan1*, Renee A. Crane2, Marielle Cardenas Valdez3, Nelly Castaneda3, Charidan L. Jackson3,  Islam Mostafa4, 5,  Wenwen Kong5,  Shweta Chhajed5 and  Sixue Chen5, 6, 7
  • 1Biological Sciences, California State University, Long Beach, United States
  • 2Milken Community High School, United States
  • 3California State University, Long Beach, United States
  • 4Department of Pharmacology and Toxicology, Faculty of Pharmacy, Zagazig University, Egypt
  • 5Genetic Institute, University of Florida, United States
  • 6Plant Molecular and Cellular Biology Program, University of Florida, United States
  • 7Interdisciplinary Center for Biotechnology Research, University of Florida, United States

Early age-related developmental senescence was observed in Arabidopsis cyp79B2/cyp79B3 double mutants that cannot produce indole-3-acetaldoxime (IAOx), the precursor to indole glucosinolates (IGs), camalexin and auxin. The early senescence phenotype was not observed when senescence was induced by darkness. The cyp79B2/cyp79B3 mutants had lower auxin levels, but did not display auxin-deficient phenotypes. Camalexin biosynthesis mutants senesced normally; however, IG-transport and exosome-related pen1/pen3 double mutants displayed early senescence. The early senescence in pen1/pen3 mutants depended on salicylic acid and was not observed in pen1 or pen3 single mutants. Quantitation of IGs showed reduced levels in cyp79B2/cyp79B3 mutants, but unchanged levels in pen1/pen3, even though both of these double mutants display early senescence. We discuss how these genetic data provide evidence that IAOx metabolite(s) are playing a protective role in leaf senescence that is dependent on proper trafficking by PEN1 and PEN3, perhaps via the formation of exosomes.

Keywords: Senescence (leaf), Senescence accelerated, IAOx, PEN1, PEN3, Exosomes

Received: 16 May 2019; Accepted: 02 Sep 2019.

Copyright: © 2019 Brusslan, Crane, Cardenas Valdez, Castaneda, Jackson, Mostafa, Kong, Chhajed and Chen. 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) and the copyright owner(s) 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: Prof. Judy Brusslan, California State University, Long Beach, Biological Sciences, Long Beach, 90840-3702, California, United States, bruss@csulb.edu