Novel proteome and acetylome of Bemisia tabaci Q in response to Cardinium infection

Abstract

Background: It has become increasingly clear that symbionts have crucial evolutionary and ecological ramifications for their host arthropods. However, little is known whether these symbiont infections influence the proteome and lysine acetylome of their host arthropods. Here we performed experiments to investigate the proteomes and acetylomes of Cardinium-infected (C^*+) and -uninfected (C^-) Bemisia tabaci Q with identical backgrounds, through the combination of affinity enrichment and high-resolution LC-MS/MS analysis.

Results: Of the 3353 proteins whose levels were quantitated in proteome, a total of 146 proteins dividing into 77 up-regulated and 69 down-regulated proteins were discovered to be differentially expressed as having at least a 1.2-fold change when C^*+ strain was compared with C^- strain. Furthermore, a total of 528 lysine acetylation sites in 283 protein groups were identified, among which 356 sites in 202 proteins were quantified. The comparison of acetylomes revealed 30 sites in 26 lysine acetylation proteins (Kac) were quantified as up-regulated targets and 35 sites in 29 Kac proteins were quantified as down-regulated targets. Functional analysis showed that these differentially expressed proteins and Kac proteins were mainly involved in diverse physiological processes related to development, immune responses and energy metabolism, such as retinol metabolism, methane metabolism and fatty acid degradation. Notably, protein interaction network analyses demonstrated widespread interactions modulated by protein acetylation.

Conclusion: Here we show the proteome and acetylom of B. tabaci Q in response to the symbiont Cardinium infection. This is the first study to utilize the tool of acetylome analysis for revealing physiological responses of arthropods to its symbiont infection, which will provide an important resource for exploring the arthropod-symbiont interaction.

Keywords: Acetylomes; Bemisia tabaci Q; Cardinium; Physiological response; Proteomes.

Fig. 1

Experimental design and schematic diagram of the workflow used in this study. The whitefly photo was taken and processed by author Hongran Li

Fig. 2

Identification of lysine acetylation in Bemisia tabaci. a Mass error distribution of all identified peptides. b Peptide length distribution. c Distribution of acetylated proteins based on their number of acetylation peptides

Fig. 3

Properties of the acetylated peptides in Bemisia tabaci. a Acetylation motifs and conservation of acetylation sites. b Number of identified modification sites in each acetylated protein. c Heat map of the amino acid compositions of the acetylation sites. (Red indicates enrichment and green identifies depletion

Fig. 4

Functional classification of differentially expressed Kac proteins compared C^*+ to C⁻ strains. a Classification of the differentially expressed Kac proteins based on biological process. b Classification of the differentially expressed lysine acetylated proteins based on molecular function. c Classification of the differentially expressed lysine acetylated proteins based on cellular component. d Subcellular localization of the differentially expressed lysine acetylated proteins

Fig. 5

Enrichment-based clustering analysis of acetylome data sets in Bemisia tabaci C^*+ and C⁻ strains. a molecular function, b biological process, c cellular compartment, d KEGG pathways, e protein domain. In each classification, all the quantified proteins were divided into four groups according to C^*+/C- ratios: Q1 (Ratio < 0.77), Q2 (0.77 < Ratio < 0.83), Q3 (1.2 < Ratio < 1.3), Q4 (Ratio > 1.3)

Fig. 6

Interaction networks of differentially expressed Kac proteins compared Bemisia tabaci C^*+ to C⁻ strains