Label-Free Quantitative Proteomic Analysis of Puccinia psidii Uredospores Reveals Differences of Fungal Populations Infecting Eucalyptus and Guava

Abstract

Puccinia psidii sensu lato (s.l.) is the causal agent of eucalyptus and guava rust, but it also attacks a wide range of plant species from the myrtle family, resulting in a significant genetic and physiological variability among populations accessed from different hosts. The uredospores are crucial to P. psidii dissemination in the field. Although they are important for the fungal pathogenesis, their molecular characterization has been poorly studied. In this work, we report the first in-depth proteomic analysis of P. psidii s.l. uredospores from two contrasting populations: guava fruits (PpGuava) and eucalyptus leaves (PpEucalyptus). NanoUPLC-MSE was used to generate peptide spectra that were matched to the UniProt Puccinia genera sequences (UniProt database) resulting in the first proteomic analysis of the phytopathogenic fungus P. psidii. Three hundred and fourty proteins were detected and quantified using Label free proteomics. A significant number of unique proteins were found for each sample, others were significantly more or less abundant, according to the fungal populations. In PpGuava population, many proteins correlated with fungal virulence, such as malate dehydrogenase, proteossomes subunits, enolases and others were increased. On the other hand, PpEucalyptus proteins involved in biogenesis, protein folding and translocation were increased, supporting the physiological variability of the fungal populations according to their protein reservoirs and specific host interaction strategies.

The Eucalyptus Cuticular Waxes Contribute in Preformed Defense Against Austropuccinia psidii

“…After the field assessment, species with enough plantlets to further assays: susceptible ( Eucalyptus grandis and Eucalyptus phaeotricha ) and resistant ( Eucalyptus urophylla , Eucalyptus camaldulensis , Eucalyptus urograndis and Eucalyptus robusta ) were selected to validate the data in controlled conditions as described by Leite et al (2013) with modifications (Quecine et al, 2016). Plantlets of each species were grown under greenhouse conditions for 120 days and transferred to a controlled growth chamber under a 12 h photoperiod (200 μmol m -1 s -1 ) at 20°C for acclimatization for 7 days.…”

Comparative Methods for Molecular Determination of Host-Specificity Factors in Plant-Pathogenic Fungi

“…A global proteomic comparison of mycelium and germinating cysts was done in two other oomycete plant pathogens, Phytophthora ramorum and P. sojae [ 85 ]. A proteome comparison was also done with uredospores from two different populations of the rust fungus Puccinia psidii isolated from eucalyptus leaves and guava fruits [ 86 ]. Mycelial proteins from isolates of the brown rot fungus Monilinia laxa were obtained from apples and apricots, and were separated by 2-D gel electrophoresis, followed by LC-MS/MS of identified differentially expressed proteins [ 87 ].…”

Sporulation: how to survive on planet Earth (and beyond)

“…Spores from only a few plant fungal pathogens have been subjected to compositional analyses, including Uromyces appendiculatus , a rust fungus infecting wheat and beans, Blumeria graminis f. sp. hordei , an ascomycete causing barley powdery mildew, Magnaporthe oryzae , the causative agent of rice blast disease, several Puccinia rust basidiomycetes, and Colletotrichum acutatum that infects several commercially valuable fruit crops (Cooper et al 2006; Noir et al 2009; Gokce et al 2012; El-Akhal et al 2013; Quecine et al 2016; Zhang et al 2015; Beinhauer et al 2016). Proteomic studies of these spores showed that proteins involved in common processes such as protein homeostasis and metabolism are readily detectable in those spores, which is consistent with stress resistance and rapid growth during germination; however, one would expect proteins involved in those processes to also be important for vegetative growth.…”