RBOH play regulatory role in the JA pathway induced by the volatile organic compound ethyl vinyl ketone

Evk (ethyl vinyl ketone) is the volatile released by plants in response to insect feeding. Evk can activate RBOH (ARABIDOPSIS THALIANA RESPIRATORY BURST OXIDASE HOMOLOG) dependent ROS burst. However, it is unknown how evk achieves resistance through RBOH protein. This study shows for the first time that RBOHF (ARABIDOPSIS THALIANA RESPIRATORY BURST OXIDASE HOMOLOG F) is a negative regulator in the JA (jasmonic acid) signal mediated by evk, and RBOHD (ARABIDOPSIS THALIANA RESPIRATORY BURST OXIDASE HOMOLOG D) is a positive regulator in the JA signal mediated by evk. Through biological experiments, we found that evk fumigation can cause the resistance of plants to plutella xylostella; Through confocal laser scanning microscopy, it was found that evk could trigger H2O2 burst and increase intracellular calcium concentration, these two biological reactions were RBOH dependent. As revealed by reverse transcription quantitative PCR (RT-qPCR) experiment, biological experiment and hormone concentration determination experiment, it was found that evk treatment can cause up regulation of JA related genes, with higher insect resistance and higher JA content. Moreover, the mutant experiment showed that RBOHF may be a negative regulator, while RBOHD is a positive regulator. In addition, CML42 (CALMODULIN-LIKE 42) was significantly up-regulated in mutant rbohd, and CML42 was down-regulated in mutant rbohf. It is possible that RBOHD, RBOHF achieve the opposite regulation mode through CML42. It was found for the first time that evk could bind to OPR (12-OXOPHYTODIENOATE REDUCTASE) by molecular docking, thus stimulating its activity and causing JA accumulation.

Automated summary

Through biological experiments, it was found that evk fumigation can enhance plants' resistance to Plutella xylostella; Confocal laser scanning microscopy revealed that evk can trigger H2O2 burst and increase intracellular calcium concentration, both of which are RBOH-dependent. RT-qPCR experiment showed that evk treatment can upregulate JA-related genes, resulting in higher insect resistance and JA content. Mutant experiments indicated that RBOHF may act as a negative regulator, while RBOHD acts as a positive regulator. Molecular docking revealed that evk can bind to OPR and stimulate its activity, leading to JA accumulation.