First molecular insights into the infection process provoked by Neofusicoccum parvum in Liquidambar styraciflua and the identification of new cysteine rich proteins in both organisms

Abstract

Background Neofusicoccum parvum belongs to Botryosphaeriaceae family that groups endophytic and latent pathogens of woody plants responsible of diseases such as cankers, dieback and blight. Is a widespread pathogen in a broad host range including agricultural, horticultural and forestry plants, therefore is relevant to characterize molecular mechanisms involved in the disease. This work, report for first time a N. parvum as a pathogen of Liquidambar styraciflua. We established an in vitro pathosystem using foliar tissue in order to characterize the infection process through scanning electron microscopy. Because cysteine rich proteins (CysRPs) are well described for their important functions under plant-pathogen interaction, new CysRPs were identified for these organisms, and mRNAs expression of these proteins was analyzed at early times during the interaction.Results Since the first 24 hours post infection, the pathogen caused visible symptoms and the microscopic analysis at 16 days post infection revealed the presence of N. parvum pycnidium immersed in L. styraciflua leaf tissue. For both organisms, two databases with transcriptomic and genomic information were analyzed and new five CysRPs were identified for each organism, the amino acid length varied between 95 and 204 and in silico analysis revealed that all proteins are potentially secreted. The search of conserved domains and phylogenetic analyses bring to light that all proteins are novel including two of N. parvum that present the well-known CFEM domain. RT-qPCR analysis was conducted at 24- and 72-hours post infection and the results showed change levels of CysRPs mRNAs for both the plant and the fungus at early times during the interaction.ConclusionsIt is recognized for first time that N. parvum is a pathogen of L. styraciflua and this work represents an approach to begin to deeply understand the molecular mechanisms involved in this interaction highlighting the potential involvement of CysRPs of both organism during this biotic stress.