The crotonylated and succinylated proteins of jujube involved in phytoplasma-stress responses

Liman Zhang; Huibin Wang; Chaoling Xue; Yin Liu; Yao Zhang; Zhiguo Liu; Xiangrui Meng; Mengjun Liu; Jin Zhao

doi:10.1186/s12915-024-01917-x

The crotonylated and succinylated proteins of jujube involved in phytoplasma-stress responses

BMC Biol. 2024 May 15;22(1):113. doi: 10.1186/s12915-024-01917-x.

Authors

Liman Zhang^{1

2}, Huibin Wang^{1

2}, Chaoling Xue^{1

2}, Yin Liu^{1

2}, Yao Zhang^{1

2}, Zhiguo Liu³, Xiangrui Meng^{1

2}, Mengjun Liu⁴, Jin Zhao^{5

6}

Affiliations

¹ College of Life Science, Hebei Agricultural University, Baoding, China.
² Hebei Key Laboratory of Plant Physiology and Molecular Pathology, Hebei Agricultural University, Baoding, China.
³ Research Center of Chinese Jujube, Hebei Agricultural University, Baoding, China.
⁴ Research Center of Chinese Jujube, Hebei Agricultural University, Baoding, China. kjliu@hebau.edu.cn.
⁵ College of Life Science, Hebei Agricultural University, Baoding, China. zhaojinbd@126.com.
⁶ Hebei Key Laboratory of Plant Physiology and Molecular Pathology, Hebei Agricultural University, Baoding, China. zhaojinbd@126.com.

Abstract

Background: Protein posttranslational modifications (PTMs) are fast and early responses to environmental changes, including pathogen infection. Jujube witches' broom (JWB) is a phytoplasma disease causing great economic loss in jujube production. After phytoplasma infection, the transcriptional, translational, and metabolic levels in jujube were activated, enabling it to survive during phytoplasma invasion. However, no study has yet reported on PTMs in jujube. Lysine crotonylation (Kcr) and lysine succinylation (Ksu) have been popular studies in recent years and their function in plant phytoplasma-stress responses remains unclear.

Results: Here, 1656 crotonylated and 282 succinylated jujube proteins were first identified under phytoplasma-stress, of which 198 were simultaneously crotonylated and succinylated. Comparative analysis revealed that 656 proteins, 137 crotonylated and 43 succinylated proteins in jujube were regulated by phytoplasma infection, suggesting that Kcr was more universal than Ksu. Kcr differentially expressed proteins (DEPs) were related to ribosomes, photosynthetic and carbon metabolism, while Ksu DEPs were mainly involved in carbon metabolism, the TCA cycle and secondary metabolite biosynthesis. The crosstalk network among proteome, crotonylome and succinylome showed that DEPs related to ribosomal, peroxidases and glutathione redox were enriched. Among them, ZjPOD51 and ZjPHGPX2 significantly increased at the protein and Kcr level under phytoplasma-stress. Notably, 7 Kcr sites were identified in ZjPHGPX2, a unique antioxidant enzyme. After inhibitor nicotinamide (NAM) treatment, GPX enzyme activity in jujube seedlings was reduced. Further, site-directed mutagenesis of key Kcr modification sites K130 and/or K135 in ZjPHGPX2 significantly reduced its activity.

Conclusions: This study firstly provided large-scale datasets of Kcr and Ksu in phytoplasma-infected jujube and revealed that Kcr modification in ZjPHGPX2 positively regulates its activity.

Keywords: Crotonylome; Enzyme activity; Inhibitor NAM; Jujube phloem; Phytoplasma-stress; Site-directed mutagenesis; Succinylome; ZjPHGPX2.

MeSH terms

Lysine / metabolism
Phytoplasma* / physiology
Plant Diseases* / microbiology
Plant Proteins* / genetics
Plant Proteins* / metabolism
Protein Processing, Post-Translational
Stress, Physiological
Ziziphus* / metabolism
Ziziphus* / microbiology