AUTHOR=Zhang Xuan-Rui , Xu You-Ping , Cai Xin-Zhong 

TITLE=SlCNGC1 and SlCNGC14 Suppress Xanthomonas oryzae pv. oryzicola-Induced Hypersensitive Response and Non-host Resistance in Tomato

JOURNAL=Frontiers in Plant Science

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2018.00285

DOI=10.3389/fpls.2018.00285

ISSN=1664-462X

ABSTRACT=<p>Mechanisms underlying plant non-host resistance to <italic>Xanthomonas oryzae</italic> pv. <italic>oryzicola</italic> (<italic>Xoc</italic>), the pathogen causing rice leaf streak disease, are largely unknown. Cyclic nucleotide-gated ion channels (CNGCs) are calcium-permeable channels that are involved in various biological processes including plant resistance. In this study, functions of two tomato <italic>CNGC</italic> genes <italic>SlCNGC1</italic> and <italic>SlCNGC14</italic> in non-host resistance to <italic>Xoc</italic> were analyzed. Silencing of <italic>SlCNGC1</italic> and <italic>SlCNGC14</italic> in tomato significantly enhanced <italic>Xoc</italic>-induced hypersensitive response (HR) and non-host resistance, demonstrating that both <italic>SlCNGC1</italic> and <italic>SlCNGC14</italic> negatively regulate non-host resistance related HR and non-host resistance to <italic>Xoc</italic> in tomato. Silencing of <italic>SlCNGC1</italic> and <italic>SlCNGC14</italic> strikingly increased <italic>Xoc</italic>-induced callose deposition and strongly promoted both <italic>Xoc</italic>-induced and flg22-elicited H<sub>2</sub>O<sub>2</sub>, indicating that these two <italic>SlCNGCs</italic> repress callose deposition and ROS accumulation to attenuate non-host resistance and PAMP-triggered immunity (PTI). Importantly, silencing of <italic>SlCNGC1</italic> and <italic>SlCNGC14</italic> apparently compromised cytosolic Ca<sup>2+</sup> accumulation, implying that SlCNGC1 and SlCNGC14 function as Ca<sup>2+</sup> channels and negatively regulate non-host resistance and PTI-related responses through modulating cytosolic Ca<sup>2+</sup> accumulation. <italic>SlCNGC14</italic> seemed to play a stronger regulatory role in the non-host resistance and PTI compared to <italic>SlCNGC1</italic>. Our results reveal the contribution of CNGCs and probably also Ca<sup>2+</sup> signaling pathway to non-host resistance and PTI.</p>