Efeito elicitor do óxido nítrico na indução do sistema de defesa do mamoeiro

Abstract

Plants possess differentmechanisms that make them resistant to diseases and pests. Thus, research groupsaround the world look out tothe role of each participant substance onplant defense biochemical system.Such studies aim, among other things, to stabilish plants that are resistant to the main diseasesthat affect the orchards. One of the main diseases that affect papaya crops in Brazil is stick disease,caused by Papaya meleira virus(PMeV). The goal of this work was to analyze papaya seedling cv. Golden defense system induction by nitric oxide (NO) and its effectiveness against PMeV. In orther todetermine the histochemical and enzymatic factors relatedto NOdefense response, including the production of reactive oxygen species(ROS), plants were treated with 10mM sodium nitroprusside (SNP), a NO donnor. Thedefense responsewere analyzed in the following period: 0, 15, 30, 45 minutes, 1, 3, 6, 24, 48 and 72 hours and 30 days after treatment. The plantresponse to NO treatment was observed in all analyzed times, showing the NO effectiveness in papaya seedlings. The stimulus triggered by SNP in the induction of superoxide dismutase and peroxidase activity maybe related to the oxidative stress, as,in order to fightit, plants develop defenses through theincrease ofantioxidant enzymes activity. Thus, we conclude that theuseof NO as anelicitor could induce the resistant response in papaya seedlings