AUTHOR=Sánchez-Rangel Diana , Chávez-Martínez Ana I. , Rodríguez-Hernández Aída A. , Maruri-López Israel , Urano Kaoru , Shinozaki Kazuo , Jiménez-Bremont Juan F. 

TITLE=Simultaneous Silencing of Two Arginine Decarboxylase Genes Alters Development in Arabidopsis

JOURNAL=Frontiers in Plant Science

VOLUME=7

YEAR=2016

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2016.00300

DOI=10.3389/fpls.2016.00300

ISSN=1664-462X

ABSTRACT=<p>Polyamines (PAs) are small aliphatic polycations that are found ubiquitously in all organisms. In plants, PAs are involved in diverse biological processes such as growth, development, and stress responses. In <italic>Arabidopsis thaliana</italic>, the arginine decarboxylase enzymes (ADC1 and 2) catalyze the first step of PA biosynthesis. For a better understanding of PA biological functions, mutants in PA biosynthesis have been generated; however, the double <italic>adc1</italic>/<italic>adc2</italic> mutant is not viable in <italic>A. thaliana</italic>. In this study, we generated non-lethal <italic>A. thaliana</italic> lines through an artificial microRNA that simultaneously silenced the two <italic>ADC</italic> genes (amiR:<italic>ADC</italic>). The generated transgenic lines (amiR:<italic>ADC</italic>-L1 and -L2) showed reduced <italic>AtADC1</italic> and <italic>AtADC2</italic> transcript levels. For further analyses the amiR:<italic>ADC</italic>-L2 line was selected. We found that the amiR:<italic>ADC</italic>-L2 line showed a significant decrease of their PA levels. The co-silencing revealed a stunted growth in <italic>A. thaliana</italic> seedlings, plantlets and delay in its flowering rate; these phenotypes were reverted with PA treatment. In addition, amiR:<italic>ADC</italic>-L2 plants displayed two seed phenotypes, such as yellow and brownish seeds. The yellow mutant seeds were smaller than <italic>adc1, adc2</italic> mutants and wild type seeds; however, the brownish were the smallest seeds with arrested embryos at the torpedo stage. These data reinforce the importance of PA homeostasis in the plant development processes.</p>