AUTHOR=NGUYEN Nga N. T. , RANWEZ Vincent , VILE Denis , SOULIE Marie Christine , DELLAGI Alia , EXPERT Dominique , GOSTI Françoise 

TITLE=Evolutionary tinkering of the expression of PDF1s suggests their joint effect on zinc tolerance and the response to pathogen attack

JOURNAL=Frontiers in Plant Science

VOLUME=5

YEAR=2014

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2014.00070

DOI=10.3389/fpls.2014.00070

ISSN=1664-462X

ABSTRACT=<p>Multigenic families of <italic>Plant Defensin type 1</italic> (<italic>PDF1</italic>) have been described in several species, including the model plant <italic>Arabidopsis thaliana</italic> as well as zinc tolerant and hyperaccumulator <italic>A. halleri</italic>. In <italic>A. thaliana, PDF1</italic> transcripts (<italic>AtPDF1</italic>) accumulate in response to pathogen attack following synergic activation of ethylene/jasmonate pathways. However, in <italic>A. halleri</italic>, <italic>PDF1</italic> transcripts (<italic>AhPDF1</italic>) are constitutively highly accumulated. Through an evolutionary approach, we investigated the possibility of <italic>A. halleri</italic> or <italic>A. thaliana</italic> species specialization in different <italic>PDF1</italic>s in conveying zinc tolerance and/or the response to pathogen attack <italic>via</italic> activation of the jasmonate (JA) signaling pathway. The accumulation of each <italic>PDF1</italic> from both <italic>A. halleri</italic> and <italic>A. thaliana</italic> was thus compared in response to zinc excess and MeJA application. In both species, <italic>PDF1</italic> paralogues were barely or not at all responsive to zinc. However, regarding the <italic>PDF1</italic> response to JA signaling activation, <italic>A. thaliana</italic> had a higher number of <italic>PDF1</italic>s responding to JA signaling activation. Remarkably, in <italic>A. thaliana</italic>, a slight but significant increase in zinc tolerance was correlated with activation of the JA signaling pathway. In addition, <italic>A. halleri</italic> was found to be more tolerant to the necrotrophic pathogen <italic>Botrytis cinerea</italic> than <italic>A. thaliana</italic>. Since <italic>PDF1</italic>s are known to be promiscuous antifungal proteins able to convey zinc tolerance, we propose, on the basis of the findings of this study, that high constitutive <italic>PDF1</italic> transcript accumulation in <italic>A. halleri</italic> is a potential way to skip the JA signaling activation step required to increase the <italic>PDF1</italic> transcript level in the <italic>A. thaliana</italic> model species. This could ultimately represent an adaptive evolutionary process that would promote a <italic>PDF1</italic> joint effect on both zinc tolerance and the response to pathogens in the <italic>A. halleri</italic> extremophile species.</p>