Alterações no eletroma durante a sinalização sistêmica e no processo de priming em plantas de cevada estimuladas por fungos patogênicos

Abstract

Under environmental conditions plants can be affected by abiotic and biotic stresses, which can be spatially heterogeneous. This means that the plant's systemic adaptive responses to its actions require long-distance stress signals, including electrical signals. Electrical signals are generated by the transient imbalance of membrane potential, caused by the influx/efflux of ions and H+ by ion channels, plasma membrane transporters and electrogenic pumps. And they influence various physiological processes. In addition, plants have a strategy that improves their defensive capacity, priming. Priming is a defense mechanism that prepares the plant's immune system for faster and/or stronger activation of cellular defenses against future exposure to different types of stress. To verify whether a local stimulus, promoted by pathogenic agents and/or chemical stimulation, generates systemic changes in the electrome of barley plants, contributing to the priming acquisition process, we developed this work consisting of two experiments. In the first experiment, it was evaluated whether stimulation of a single leaf by pathogenic fungi, with different modes of parasitism, transmits systemic electrical signals to the rest of the plant. In the second experiment, it was evaluated whether local elicitation with jasmonic acid or Bipolaris. Sorokiniana, cause systemic physiological changes, such as defense mechanisms linked to oxidative stress. In this second case, we wanted to know if the electrome could have a signaling role in the priming acquisition process. The results obtained in the first experiment revealed that inoculation with pathogenic fungi generated specific characteristics in the distribution of electrome variation over time for each pathogen. We verified that inoculation with different species generated an electrical signature in the plant specific to each pathogen, making it possible to identify the presence of the pathogen in the plant in the first minutes. The results of the second experiment showed that the local application of jasmonic acid (AJ) and the infection by B. sorokiniana caused alterations in the local and systemic expression (far from the application site) in the defense mechanisms linked to oxidative stress, as well as drastically reduced the infection caused by the second inoculation with B. sorokiniana. We can conclude that local application of the pathogenic fungus, as well as AJ, induce long-distance signaling, triggering a priming effect in systemic tissues. However, further analysis of the electrome is needed to confirm whether, in fact, electrical signals are present in the priming acquisition process.