An improved method to study Phytophthora cinnamomi Rands zoospores interactions with host

Abstract

The pathogen Phytophthora cinnamomi Rands (Pc) is one of the ten most widespread phytopathogens in the world causing crown rot, canker and root rot in multi-functional land plants. Pc has a disastrous impact on the surrounding environment and biodiversity of flora, fauna and soil. Pc infects more than 5,000 species, including Quercus suber, Quercus ilex, Castanea sativa, Eucalyptus globulus, Persea americana (avocado), Zea mays (maize) and Solanum lycopersicon (tomato). The efficient spread of Pc depends on the short survival of asexually motile zoospores (Zs), which move through water currents until they penetrate the host roots. Due to the complexity of the life cycle, the management of Zs in the laboratory has remained quite complex for decades. The production of Zs requires mimicking nature by following a complex protocol of circular steps of growth, drought and flooding. Similar to other pathogens, the artificial growth conditions induce a rapid loss of virulence, making it necessary to add additional steps of plant infection in between these other steps. In this work, the study of the survival of Zs under different conditions has allowed us to obtain a "ready-to-use" stable stock of Zs with a high capacity to infect the host by direct freezing in liquid nitrogen. Obtaining this stock prevents the loss of virulence of Pc between cultures, thus greatly simplifying the process of inoculating plants and studying Pc with their host.