AUTHOR=Yoo Youngchul , Park Jong-Chan , Cho Man-Ho , Yang Jungil , Kim Chi-Yeol , Jung Ki-Hong , Jeon Jong-Seong , An Gynheung , Lee Sang-Won 

TITLE=Lack of a Cytoplasmic RLK, Required for ROS Homeostasis, Induces Strong Resistance to Bacterial Leaf Blight in Rice

JOURNAL=Frontiers in Plant Science

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2018.00577

DOI=10.3389/fpls.2018.00577

ISSN=1664-462X

ABSTRACT=<p>Many scientific findings have been reported on the beneficial function of reactive oxygen species (ROS) in various cellular processes, showing that they are not just toxic byproducts. The double-edged role of ROS shows the importance of the regulation of ROS level. We report a gene, <italic>rrsRLK</italic> (required for ROS-scavenging receptor-like kinase), that encodes a cytoplasmic RLK belonging to the non-RD kinase family. The gene was identified by screening rice RLK mutant lines infected with <italic>Xanthomonas oryzae</italic> pv. <italic>oryzae</italic> (<italic>Xoo</italic>), an agent of bacterial leaf blight of rice. The mutant (Δ<italic>rrsRLK</italic>) lacking the <italic>Os01g02290</italic> gene was strongly resistant to many <italic>Xoo</italic> strains, but not to the fungal pathogen <italic>Magnaporthe grisea</italic>. Δ<italic>rrsRLK</italic> showed significantly higher expression of <italic>OsPR1a</italic>, <italic>OsPR1b</italic>, <italic>OsLOX</italic>, <italic>RBBTI4</italic>, and jasmonic acid-related genes than wild type. We showed that rrsRLK protein interacts with OsVOZ1 (vascular one zinc-finger 1) and OsPEX11 (peroxisomal biogenesis factor 11). In the further experiments, abnormal biogenesis of peroxisomes, hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) accumulation, and reduction of activity of ROS-scavenging enzymes were investigated in Δ<italic>rrsRLK</italic>. These results suggest that the enhanced resistance in Δ<italic>rrsRLK</italic> is due to H<sub>2</sub>O<sub>2</sub> accumulation caused by irregular ROS-scavenging mechanism, and rrsRLK is most likely a key regulator required for ROS homeostasis in rice.</p>