Profiling of Zea mays L. proteome at early stages of compatible interactions with Meloidogyne arenaria indicates changes in signaling, oxidative stress responses, and S-adenosylmethionine biosynthesis

Root-knot nematodes (RKNs) are distributed worldwide group of plant parasitic nematodes, with a very wide host range, including mono- and dicotyledonous hosts. Meloidogyne arenaria is, next to M. hapla, M. incognita, and M. javanica, one of the most economically important species from this genus. RKNs during parasitism hijack host metabolism to establish giant cells and to break down plant defense mechanisms. To date, studies on the interaction of RKN with maize (Zea mays L.) have been underrepresented, and a description of the early response to attack by these nematodes, vital to understanding the process, is scarce in the literature. We hypothesize that in the early stage of maize response to M. arenaria infection, significant changes in the accumulation level of proteins mainly related to plant defense response, plant cell wall modifications, and phytohormone biosynthesis can be observed. In this study, a mass spectrometry approach and a label-free quantification technique were used to assess the qualitative and quantitative composition of proteins changes in the proteome of maize roots after M. arenaria infection. We used a susceptible maize variety and carried out analyses of plant proteome at two time points: 24 hours after nematode inoculation and 3 days after inoculation. Statistical analyses of significant differences between protein intensities were performed for the datasets obtained from healthy and M. arenaria-infected plants, and differentially expressed proteins (DEPs), with both lower and higher abundance were determined. DEPs were mapped, classified to the gene ontology (GO) terms into functional categories, and assigned to appropriate Kyoto Encyclopedia of Genes and Genomes (KEGG) processes and pathways. As a result, a total of 3,743 proteins were identified with 124 DEPs at 24 hpi and 66 at 3 dpi, and significant changes in the accumulation of proteins associated with processes such as cell wall modifications, reaction to stress, as well as processes and pathways related to phenylpropanoid biosynthesis and metabolism, signal transduction and to S-adenosylmethionine biosynthesis.