Abstract
Plant activators are agrochemicals that protect crops from diseases by activating the plant immune system. To isolate lead compounds for use as practical plant activators, we screened two different chemical libraries composed of various bioactive substances by using an established screening procedure that can selectively identify immune-priming compounds. We identified and characterized a group of sulfonamide compounds – sulfameter, sulfamethoxypyridazine, sulfabenzamide, and sulfachloropyridazine – among the various isolated candidate molecules. These sulfonamide compounds enhanced the avirulent Pseudomonas-induced cell death of Arabidopsis suspension cell cultures and increased disease resistance in Arabidopsis plants against both avirulent and virulent strains of the bacterium. These compounds did not prevent the growth of pathogenic bacteria in minimal liquid media at 200 μM. They also did not induce the expression of defense-related genes in Arabidopsis seedlings, at least not at 24 and 48 h after treatment, suggesting that they do not act as salicylic acid analogs. In addition, although sulfonamides are known to be folate biosynthesis inhibitors, the application of folate did not restore the potentiation effects of the sulfonamides on pathogen-induced cell death. Our data suggest that sulfonamides potentiate Arabidopsis disease resistance by their novel chemical properties.
Highlights
Plants have an innate immune system that requires the phytohormone salicylic acid (SA) for disease resistance against pathogens, including fungi, bacteria, and viruses (Vlot et al, 2009)
ISOLATION OF FOUR SULFONAMIDES AS PLANT IMMUNE-PRIMING COMPOUNDS By using the previously established chemical screening system (Noutoshi et al, 2012a), we tried to identify compounds that enhance but not induce the death of Arabidopsis suspensioncultured cells triggered by infection with avirulent pathogenic Pst-avrRpm1
In this study, we screened two different chemical libraries by using the established high-throughput chemical screening method for plant immune-priming compounds (Noutoshi et al, 2012a). Both chemical libraries are composed of bioactive substances and natural products, and the sulfonamide compounds were independently identified from each library (Figure 1)
Summary
Plants have an innate immune system that requires the phytohormone salicylic acid (SA) for disease resistance against pathogens, including fungi, bacteria, and viruses (Vlot et al, 2009). Plants recognize pathogen-derived effector molecules by using cytosolic immune sensors and activate SA biosynthesis to mount disease resistance responses (Dangl and Jones, 2001). This often results in a hypersensitive response (HR) that leads to the rapid induction of programed cell death at sites of infection (Mur et al, 2008). Plant activators are agrochemicals that confer disease resistance to crops by activating plant immune systems Due to their nature, plant activators work on host plants and not on pathogens; no drug-resistant microbes have emerged as a result of their longstanding use in the fields. The precise mode of action of probenazole has not yet been identified
Sign-in/Register to view highlights & summary 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.
