AUTHOR=Ravichandran Sridhar , Stone Sophia , Benkel Bernhard , Zhang Junzeng , Berrue Fabrice , Prithiviraj Balakrishnan 

TITLE=Optimal level of purple acid phosphatase5 is required for maintaining complete resistance to Pseudomonas syringae

JOURNAL=Frontiers in Plant Science

VOLUME=6

YEAR=2015

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2015.00568

DOI=10.3389/fpls.2015.00568

ISSN=1664-462X

ABSTRACT=<p>Plants possess an exceedingly complex innate immune system to defend against most pathogens. However, a relative proportion of the pathogens overcome host's innate immunity and impair plant growth and productivity. We previously showed that mutation in <italic>purple acid phosphatase</italic> (<italic>PAP5</italic>) lead to enhanced susceptibility of <italic>Arabidopsis</italic> to the bacterial pathogen <italic>Pseudomonas syringae</italic> pv. <italic>tomato</italic> DC3000 (<italic>Pst</italic> DC3000). Here, we report that an optimal level of <italic>PAP5</italic> is crucial for mounting complete basal resistance. Overexpression of <italic>PAP5</italic> impaired <italic>ICS1, PR1</italic> expression and salicylic acid (SA) accumulation similar to <italic>pap5</italic> knockout mutant plants. Moreover, plant overexpressing <italic>PAP5</italic> was impaired in H<sub>2</sub>O<sub>2</sub> accumulation in response to <italic>Pst</italic> DC3000. <italic>PAP5</italic> is localized in to peroxisomes, a known site of generation of reactive oxygen species for activation of defense responses. Taken together, our results demonstrate that optimal levels of <italic>PAP5</italic> is required for mounting resistance against <italic>Pst</italic> DC3000 as both knockout and overexpression of <italic>PAP5</italic> lead to compromised basal resistance.</p>