Phytophthora-citrus interactions and management strategies: a review

Abstract

Citrus production is declining worldwide due to several biotic and abiotic factors. The diseases caused by Phytophthora spp. present major economic risks since they are soil-borne and spread quickly if environmental conditions are favorable, or irrigation is poorly managed. Phytophthora species are present in all citrus-producing areas around the world causing significant losses in crop yield and affecting tree health. Bark infection, damping-off, root rot, gummosis, brown rot, and cortical root rot are among the typical symptoms caused by Phytophthora spp. The pathogenicity of Phytophthora spp. depends mainly on the specific interactions between the isolates and citrus cultivars. The use of molecular technologies has allowed the study of Phytophthora-citrus interactions, leading to the identification of several classes of effector proteins secreted by Phytophthora spp. that challenge plant homeostasis and contribute in different ways to disease development and the elucidation of defense mechanisms employed by the host plant. Comprehensive management is need of time to conquer Phytophthora spp. for better root health and citrus productivity.