ABSTRACT: Soybean is one of the most important sources of food, protein, and oil in the world. Reductions in grain number and quality are caused by different biotic stresses. One of the most common is the phytophagous mite Tetranychus urticae Koch (Acari: Tetranychidae), which inhibits plant growth and grain production. The identification of plant responses to early and late T. urticae infestation is important for a better understanding of the mite-plant interaction. We therefore aimed to evaluate the physiological and molecular responses of soybean plants to mite infestation for 5 and 21 days. Visual and microscopic symptoms of leaf damage, H2O2 accumulation, and lipid peroxidation increased consistently throughout the infestation period, while shoot length/dry weight, chlorophyll level, and number of days to reach specific developmental stages were negatively affected by T. urticae infestation. Using proteomic analysis, we identified 185 and 266 differentially abundant proteins after early (5 days) and late (21 days) mite infestation, respectively, which suggests a complex remodeling of diverse metabolic pathways. GO, KEGG, and protein-protein interaction analyses indicated that photorespiration, chlorophyll synthesis, amino acid metabolism, Krebs cycle/energy production, mitochondrial translation, nucleotide salvage, PS II assembly, and reductive pentose-P cycle are all impacted after both early and late infestation. Specific metabolic pathways modified only after early infestation include cell wall modification, cytoskeleton composition, cell division, and lysine/histidine metabolism, while JA biosynthesis, antioxidant system, S-adenosyl methionine cycle, PS II repair, cysteine/methionine/glutathione/ascorbate/-linolenic acid/selenocompound metabolism, arginine biosynthesis, and proteasome are modified only after late infestation. These differentially abundant proteins can be used as biotechnological tools in future breeding programs aiming at increased resistance to mite infestation.
Raul Sperotto 