Effects of Exogenously applied palmitic acid on systemic resistance against Fusarium oxysporum f. sp. niveum in watermelon (Citrullus lanatus (Thunb.) Matsum. et Nakai)

Abstract

e studied the effects of exogenously applied palmitic acid (PA) on reactive oxygen species (ROS) production, defense-related enzyme activity and malondialdehyde (MDA) content of roots and analyzed the response of defense-related genes in Fusarium oxysporum f.sp.niveum (FON) inoculated watermelon (Citrullus lanatus (Thunb.) Matsum. et Nakai). Our results showed that as compared to control, PA reduced the morbidity of Fusarium wilt by 33.3 % and disease severity by 53.2 %, increased the level of ROS of watermelon roots at early infection stage and the activity of defense related enzymes, and decreased the MDA content of watermelon roots. Moreover, PA up-regulated the expression of disease defense-related genes. These results suggested that PA promoted the accumulation of ROS and up-regulated the transcript level of defense-related genes and eventually induced the systemic resistance in watermelon against FON.