Abstract
Acibenzolar-S-methyl (ASM) is a well-known plant activator, which is a synthetic analog of salicylic acid (SA). Recently, copper fungicides and antibiotics are major strategies for controlling bacterial diseases. However, resistant strains have already been found. Therefore, there is an increasing demand for sustainable new disease control strategies. We investigated the ASM disease control effect against Pseudomonas cannabina pv. alisalensis (Pcal), which causes bacterial blight on Japanese radish. In this study, we demonstrated that ASM effectively suppressed Pcal disease symptom development associated with reduced bacterial populations on Japanese radish leaves. Interestingly, we also demonstrated that ASM activated systemic acquired resistance (SAR), including stomatal-based defense on ASM-untreated upper and lower leaves. Reactive oxygen species (ROS) are essential second messengers in stomatal-based defense. We found that ASM induced stomatal closure by inducing ROS production through peroxidase. These results indicate that stomatal closure induced by ASM treatment is effective for preventing Pcal pathogen invasion into plants, and in turn reduction of disease development.
Highlights
Several bacterial pathogens were identified as causal agents of severe worldwide epidemics
For expression profiles of Japanese radish defense genes in response to ASM, plants were dip-treated with water as a control or ASM on fourth leaves
Radish Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) gene was used as an internal control
Summary
Several bacterial pathogens were identified as causal agents of severe worldwide epidemics. Discoloration of roots and necrotic leaf lesions has serious implications for the commercial value of Japanese radish Chemical treatments such as copper fungicides and antibiotics are popular strategies for bacterial disease control. SAR genes were rapidly and highly expressed in upper leaves after first leaf treatment with ASM (Narusaka et al, 1999, 2001; Cools and Ishii, 2002). We demonstrated that ASM protects cabbage plants from Pcal by activating stomatal-based defense (Ishiga et al, 2020). ASM induced expression of SAR marker genes including PR1, PR2, and PR5 in cabbage plants (Ishiga et al, 2020). We demonstrate that ASM successfully suppressed disease development and bacterial multiplication in Japanese radish by activating stomatal defense. Our results highly support that ASM can be an additional disease management tool to prevent crop disease losses against bacterial pathogens
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.
