AUTHOR=Sequera-Mutiozabal Miren I. , Erban Alexander , Kopka Joachim , Atanasov Kostadin E. , Bastida Jaume , Fotopoulos Vasileios , Alcázar Rubén , Tiburcio Antonio F. 

TITLE=Global Metabolic Profiling of Arabidopsis Polyamine Oxidase 4 (AtPAO4) Loss-of-Function Mutants Exhibiting Delayed Dark-Induced Senescence

JOURNAL=Frontiers in Plant Science

VOLUME=7

YEAR=2016

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2016.00173

DOI=10.3389/fpls.2016.00173

ISSN=1664-462X

ABSTRACT=<p>Early and more recent studies have suggested that some polyamines (PAs), and particularly spermine (Spm), exhibit anti-senescence properties in plants. In this work, we have investigated the role of <italic>Arabidopsis Polyamine Oxidase 4</italic> (<italic>PAO4</italic>), encoding a PA back-conversion oxidase, during dark-induced senescence. Two independent <italic>PAO4</italic> (<italic>pao4-1</italic> and <italic>pao4-2</italic>) loss-of-function mutants have been found that accumulate 10-fold higher Spm, and this associated with delayed entry into senescence under dark conditions. Mechanisms underlying <italic>pao4</italic> delayed senescence have been studied using global metabolic profiling by GC-TOF/MS. <italic>pao4</italic> mutants exhibit constitutively higher levels of important metabolites involved in redox regulation, central metabolism and signaling that support a priming status against oxidative stress. During senescence, interactions between PAs and oxidative, sugar and nitrogen metabolism have been detected that additively contribute to delayed entry into senescence. Our results indicate the occurrence of metabolic interactions between PAs, particularly Spm, with cell oxidative balance and transport/biosynthesis of amino acids as a strategy to cope with oxidative damage produced during senescence.</p>