AUTHOR=Liu Furong , Zhang Weiguo , Schwessinger Benjamin , Wei Tong , Ruan Deling , Ronald Pamela 

TITLE=The Rice Xa3 Gene Confers Resistance to Xanthomonas oryzae pv. oryzae in the Model Rice Kitaake Genetic Background

JOURNAL=Frontiers in Plant Science

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2020.00049

DOI=10.3389/fpls.2020.00049

ISSN=1664-462X

ABSTRACT=<p>The rice XA21 and XA3 pattern receptor kinases, derived from <italic>Oryza longistaminata</italic> and an <italic>Oryza. sativa japonica</italic> cultivar Wase Aikoku 3, respectively, confer resistance to strains of the Gram-negative bacterium <italic>Xanthomonas oryzae</italic> pv. <italic>oryzae</italic> (<italic>Xoo</italic>), the causal agent of rice bacterial blight disease. Previously, we showed that transfer of <italic>Xa21</italic> to the model rice cultivar Kitaake enhances resistance to <italic>Xoo</italic>. In this manuscript we demonstrate that Kitaake expressing <italic>Xa3</italic> confers resistance to <italic>Xoo</italic> strain PXO79 and that the stress-related marker genes <italic>PR10b</italic> and <italic>KO5</italic> are upregulated in <italic>Xoo</italic>-infected <italic>Xa3</italic> rice leaves. We also show that rice somatic embryogenesis receptor kinase 2 (OsSERK2) positively regulates XA3-mediated immunity in Kitaake. We found that overexpression of XA21 binding protein 15 (XB15) and XB24, two negative regulators of XA21-mediated immunity, do not affect XA3-mediated immunity in the Kitaake genetic background. Our results indicate that the rice immune receptors XA21 and XA3 employ both shared and distinct signaling components in their response to <italic>Xoo</italic>. The results are important to further understand pathogen-associated molecular pattern (PAMP)-triggered immunity in rice. Furthermore, the presence of Kitaake rice carrying <italic>Xa3</italic> will facilitate genetic research to study the XA3-mediated immunity.</p>