AUTHOR=Sheng Cong , Yu Dongli , Li Xuan , Yu Hanxi , Zhang Yimai , Saqib Bilal Muhammad , Ma Hongyu , Zhang Xin , Baig Ayesha , Nie Pingping , Zhao Hongwei 

TITLE=OsAPX1 Positively Contributes to Rice Blast Resistance

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.843271

DOI=10.3389/fpls.2022.843271

ISSN=1664-462X

ABSTRACT=<p>Ascorbate peroxidases (APXs) maintain cellular reactive oxygen species (ROS) homeostasis through their peroxidase activity. Here, we report that <italic>OsAPX1</italic> also promotes ROS production such that a delicate cellular ROS homeostasis is achieved temporally after <italic>Magnaporthe oryzae</italic> infection. <italic>OsAPX1</italic> specifically induces ROS production through increasing respiratory burst oxidase homologs (<italic>OsRBOHs</italic>) expression and can be inhibited by DPI, a ROS inhibitor. The time-course experiment data show that the simultaneous induction of <italic>OsAPX1</italic> and <italic>OsRBOHs</italic> leads to ROS accumulation at an early stage; whereas a more durable expression of <italic>OsAPX1</italic> leads to ROS scavenging at a later stage. By the temporal switching between ROS inducer and eliminator, <italic>OsAPX1</italic> triggers an instant ROS burst upon <italic>M. oryzae</italic> infection and then a timely elimination of ROS toxicity. We find that <italic>OsAPX1</italic> is under the control of the miR172a-<italic>OsIDS1</italic> regulatory module. <italic>OsAPX1</italic> also affects salicylic acid (SA) synthesis and signaling, which contribute to blast resistance. In conclusion, we show that <italic>OsAPX1</italic> is a key factor that connects the upstream gene silencing and transcription regulatory routes with the downstream phytohormone and redox pathway, which provides an insight into the sophisticated regulatory network of rice innate immunity.</p>