Abstract
The reactive oxygen species (ROS) burst is the most common plant immunity mechanism to prevent pathogen infection, although the exact role of ROS in plant immunity has not been fully elucidated. We investigated the expression and translocation of Oryza sativa respiratory burst oxidase homologue B (OsRBOHB) during compatible and incompatible interactions between rice epidermal cells and the pathogenic fungus Pyricularia oryzae (syn. Magnaporthe oryzae). We characterized the functional role of ROS focal accumulation around invading hyphae during P. oryzae infection process using the OsRBOHB inhibitor diphenyleneiodonium (DPI) and the actin filament polymerization inhibitor cytochalasin (Cyt) A. OsRBOHB was strongly induced during incompatible rice–P. oryzae interactions, and newly synthesized OsRBOHB was focally distributed at infection sites. High concentrations of ROS focally accumulated at the infection sites and suppressed effector biotrophy-associated secreted (BAS) proteins BAS4 expression and invasive hyphal growth. DPI and Cyt A abolished ROS focal accumulation and restored P. oryzae effector BAS4 expression. These results suggest that ROS focal accumulation is able to function as an effective immune mechanism that blocks some effectors including BAS4-expression during P. oryzae infection. Disruption of ROS focal accumulation around invading hyphae enables successful P. oryzae colonization of rice cells and disease development.
Highlights
Plant pathogen effectors facilitate parasitism by suppressing pathogen-associated molecular pattern (PAMP) perception or modifying plant physiology to support pathogen growth and colonization [1,2,3]
We demonstrated that a majority of Oryza sativa respiratory burst oxidase homologue B (OsRBOHB) was localized around the invasive hyphae in incompatible rice–P. oryzae interactions, but this OsRBOHB re-distribution did not occur in compatible rice–P. oryzae interactions (Figure 1B)
We propose that reactive oxygen species (ROS) focal accumulation around invasive hyphae can have an effective role in inhibiting pathogen infection
Summary
Plant pathogen effectors facilitate parasitism by suppressing pathogen-associated molecular pattern (PAMP) perception or modifying plant physiology to support pathogen growth and colonization [1,2,3]. We report that ROS focally accumulated around invasive P. oryzae hyphae in rice cells during incompatible rice–P. oryzae interactions. Distinct localization of OsRBOHB around the infection site was correlated to ROS accumulation around invasive hyphae and inhibited effector BAS4 expression during incompatible interactions. ROS focal accumulation around invasive hyphae did not occur during compatible interactions These combined results suggest that altered localization of OsRBOHB at the infection sites enables high concentration of ROS to accumulate around the avirulent P. oryzae invasive hyphae during incompatible interactions, which can prevent the expression and secretion of pathogen effector BAS4 and promote rice immunity
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
