Metabolic discrimination of citrus species resistant and susceptible to black spot disease using multi-platform-based metabolomic approach

Abstract

Citrus black spot (CBS) caused by the fungus Phyllosticta citricarpa. CBS causes several economic damages to commercial citrus orchards, such as fruit blemishes and premature fruit drop, leading to yield loss. There are few studies related to the profile of compounds associated with the Citrus- P. citricarpa relationship. Thus, this study aimed to i) investigate the metabolic changes in leaves of two citrus species, Citrus limon (lemon) and Citrus latifolia (Tahiti lime), susceptible and resistant to citrus black spot disease, respectively, inoculated with the P. citricarpa; ii) have a general view of all metabolites present in citrus plants by using different metabolomics-based platforms, and iii) understand the mechanism that is supposed to be involved in citrus defense against this pathogen. Different analytical platforms, such as NMR, LC-MS, HPTLC and GC-MS were used. In addition, chemometrics tools were applied and as result, coumarins were observed at higher concentrations in C. latifolia specie after inoculation with the pathogen. Moreover, metabolomic of the pathogen was also investigated using molecular networking- GNPS platform which showed the diversity of compounds that may be produced by this fungus. This work provides a better understanding of the metabolic profile of resistant and susceptible citrus challenged by P. citricarpa as well as the compounds associated with the defense of plants against the pathogen.