Identification and quantification of hormones produced during the interaction of melon plants (Cucumis Melo L.) with the pathogen Monosporascus Cannonballus

The fungus Monosporascus cannonballus is a pathogen that causes a severe disease called vine decline, which is found in areas where melons and watermelons are cultivated worldwide. Nevertheless, few studies have examined the hormones involved in host-pathogen interactions. Thus, this study was conducted to identify and quantify these metabolites. The varieties USA PI 124,104 (resistant) and TAM-Uvalde (susceptible) were inoculated with the pathogen, and the hormones were quantified before inoculation (0 h) and 24, 48, and 72 h after inoculation employing ultra-performance liquid chromatography analysis. The hormone levels varied over time. Peculiarly, gibberellic acid and kinetin were detected 24 and 48 h after inoculation, which may be indicative of their synthesis by the fungus. Likewise, methyl jasmonate was detected 48 h after inoculation, a time at which the pathogen could also have produced it. Additionally, salicylic and jasmonic acids were detected, and their concentrations varied antagonistically over time. Interestingly, jasmonic acid could also have been synthesized by the fungus, suggesting a hemibiotrophic lifestyle. Hence, further studies are needed to identify the origins of kinetin, methyl jasmonate, gibberellic and jasmonic acids.