Abstract

Essential oils, hydrolates and some homeopathic substances derived from essential oils are alternatives for the control of pathogenic fungi. The molecular effect of several essential oils is still unknown and there is no research on the effect of hydrolates and homeopathic substances. The objective was to evaluate in vitro the effect of essential oil, hydrolate, and homeopathic oil from Tagetes remotiflora and Tween 20 (TW) against B. cinerea; as well as to determine the expression of B. cinerea genes due to the effect of hydrolate and Tween 20. The in vitro inhibition effect of these substances was evaluated in culture media. Essential oil and hydrolate were the most effective treatments in inhibiting the growth of B. cinerea, while Tween 20 and homeopathic oil had a lesser effect. RNA-seq was used to identify differentially expressed genes (DEGs) in response to the treatments evaluated in vitro. In response to hydrolate, 1,662 DEGs were found, 1,314 down-regulated and 348 up-regulated. With Tween 20, 791 DEGs were found, 456 down-regulated and 335 up-regulated. Due to the low effect of the homeopathic essential oil on B. cinerea, no DEGs were found. The high inhibition of the essential oil on the fungus did not allow its sequencing because RNA of sufficient quantity and quality was not obtained. The hydrolate affected pathways related to amino acids and carbohydrates; while Tween 20 affected the peroxisome and fatty acid metabolism. In vitro evaluation and transcriptomic analysis confirmed that the essential oil and hydrolate of T. remotiflora have potential application against B. cinerea, without detracting from the importance of the surfactant.

Keywords

essential oil, gray mold, homeopathic oil, inhibition, transcriptomic analysis, tween 20