AUTHOR=Vega-Arreguín Julio C. , Shimada-Beltrán Harumi , Sevillano-Serrano Jacobo , Moffett Peter 

TITLE=Non-host Plant Resistance against Phytophthora capsici Is Mediated in Part by Members of the I2 R Gene Family in Nicotiana spp.

JOURNAL=Frontiers in Plant Science

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2017.00205

DOI=10.3389/fpls.2017.00205

ISSN=1664-462X

ABSTRACT=<p>The identification of host genes associated with resistance to <italic>Phytophthora capsici</italic> is crucial to developing strategies of control against this oomycete pathogen. Since there are few sources of resistance to <italic>P. capsici</italic> in crop plants, non-host plants represent a promising source of resistance genes as well as excellent models to study <italic>P. capsici</italic> – plant interactions. We have previously shown that non-host resistance to <italic>P. capsici</italic> in <italic>Nicotiana</italic> spp. is mediated by the recognition of a specific <italic>P. capsici</italic> effector protein, PcAvr3a1 in a manner that suggests the involvement of a cognate disease resistance (R) genes. Here, we have used virus-induced gene silencing (VIGS) and transgenic tobacco plants expressing dsRNA in <italic>Nicotiana</italic> spp. to identify candidate <italic>R</italic> genes that mediate non-host resistance to <italic>P. capsici</italic>. Silencing of members of the <italic>I2</italic> multigene family in the partially resistant plant <italic>N. edwardsonii</italic> and in the resistant <italic>N. tabacum</italic> resulted in compromised resistance to <italic>P. capsici</italic>. VIGS of two other components required for <italic>R</italic> gene-mediated resistance, <italic>EDS1</italic> and <italic>SGT1</italic>, also enhanced susceptibility to <italic>P. capsici</italic> in <italic>N. edwardsonii</italic>, as well as in the susceptible plants <italic>N. benthamiana</italic> and <italic>N. clevelandii</italic>. The silencing of <italic>I2</italic> family members in <italic>N. tabacum</italic> also compromised the recognition of PcAvr3a1. These results indicate that in this case, non-host resistance is mediated by the same components normally associated with race-specific resistance.</p>