Brazil is one of the largest citrus producers in the world, but also one of the largest importers of pesticides for this crop, as insecticide, fungicide and bactericide. The main biotic diseases in citrus include citrus variegated chlorosis (CVC), citrus canker, leprosy, sadness, black spot, brown spot, sudden death, melanosis, rubelose, and more recently, HLB (ex-greening), and many other pests. An alternative to inhibit the growth of fungus or bacterium is to understand the metabolic events related to communication between these and the host plant. These studies may lead to new fungicides and bactericides less harmful to the environment. In this project we will study the chemical variation in Citrus species after inoculation of fungi Erythricium salmonicolor and Diaporthe citri, which are responsible for Rubelose and Melanosis diseases. The rubelose citrus has caused significant damage to the São Paulo citrus industry in recent years. The disease affects all citrus crops, and it occurs on the twigs and branches, and is more severe in vigorous trees and in dense groves. Early symptoms consist of lesions with detachment of the bark and gum exudation. Subsequently, we can observe mycelial cords and pink mycelial growth on the affected branches. The melanose cause damage to the green organs of the plant at the beginning of its development. It also affects the mature fruit or after harvest causing stem-end rots. In unkempt orchards, melanosis may result in losses, mainly due to the appearance of the fruit supplied to the fresh fruit market. The secondary metabolites that a microorganism synthesizes are related to their respective ecological niche. This not only synthesize metabolites need to compete with other pathogens, but also to colonize the host, and presumably to regulate the host metabolism in a balanced combination. E. salmonicolor e e Diaporthe citri inside the citrus plant form a plant-microorganism interaction interesting to be studied. An alternative to understand and therefore to inhibit the growth of the fungus is also undertake the chemical study of both. Therefore the second goal of the project is to isolate the molecules involved in the development of both fungi. These studies will be conducted through the development of analytical methods such as HPLC-UV, LC-MS / MS, LC-UV-SPE-NMR and chemometric tools.
News published in Agência FAPESP Newsletter about the scholarship: