Fungal Induced Protein Hyperacetylation Identified by Acetylome Profiling

Abstract

Lysine acetylation is a key post-translational modification that regulates diverse proteins involved in a range of biological processes. The role of histone acetylation in plant defense is well established and it is known that pathogen effector proteins encoding acetyltransferses can directly acetylate host proteins to alter immunity. However, it is unclear whether endogenous plant enzymes can modulate protein acetylation during an immune response. Here we investigate how the effector molecule HC-toxin, a histone deacetylase inhibitor, produced by Cochliobolus carbonum race 1 promotes pathogen virulence in maize through altering protein acetylation. Using mass spectrometry we globally quantified the abundance of 3,636 proteins and the levels of acetylation at 2,791 sites in maize plants treated with HC-toxin as well as HC-toxin deficient or producing strains of C. carbonum. Analyses of these data demonstrate that acetylation is a widespread post-translational modification impacting proteins encoded by many intensively studied maize genes. Furthermore, the application of exogenous HC-toxin enabled us to show that the activity of plant-encoded enzymes can be modulated to alter acetylation of non-histone proteins during an immune response. Collectively, these results provide a resource for further mechanistic studies examining the regulation of protein function and offer insight into the complex immune response triggered by virulent C. carbonum.

From prediction to function: Current practices and challenges towards the functional characterization of type III effectors

“…Such a method was used to monitor proteome changes in early and later stages of P. syringae infection (Fan et al, 2019). Similarly, it can be applied to investigate the effect of a microbe on the posttranslational modifications of the host (Walley et al, 2018).…”

Global analysis of lysine 2-hydroxyisobutyrylation during Fusarium graminearum infection in maize

“…Post-translational modification (PTM) plays a key role in the regulation of protein function in maize, such as protein acetylation is involved in the biological process of responding to Cochliobolus carbonum infection (Waszczak et al, 2015;Walley et al, 2018). To investigate the distribution of post-translational modification in the proteins of maize, we performed western blot assaying using pan-Khib, pan-Kcr, and pan-Ksucc antibodies (Figure 1).…”

Histone modification and chromatin remodeling in plant response to pathogens

“…The cyclic tetrapeptide HC-toxin (HCT) from the filamentous fungus Cochliobolus (formerly Helminthosporium) carbonum inhibits enzymatic activities of numerous HDACs in vitro (Brosch et al, 1995). HCT treatments of maize (Zea mays L.) led to hyperacetylation of histones H3 and H4 as well as non-histone proteins including the TPL-homolog RAMOSA1 ENHANCER LOCUS 2 (REL2; Ransom and Walton, 1997;Walley et al, 2018). It is likely that HCT promotes the establishment of pathogenic compatibility between Cochliobolus carbonum and maize by interfering with the reversible acetylation of histones and/or non-histone transcription regulators.…”