The rolB plant oncogene affects multiple signaling protein modules related to hormone signaling and plant defense

Victor P. Bulgakov,Dmitry V. Bulgakov,Galina N. Veremeichik,Yulia V. Vereshchagina,Yuri N. Shkryl

doi:10.1038/s41598-018-20694-6

Abstract

The rolB plant oncogene of Agrobacterium rhizogenes perturbs many biochemical processes in transformed plant cells, thereby causing their neoplastic reprogramming. The oncogene renders the cells more tolerant to environmental stresses and herbicides and inhibits ROS elevation and programmed cell death. In the present work, we performed a proteomic analysis of Arabidopsis thaliana rolB-expressing callus line AtB-2, which represents a line with moderate expression of the oncogene. Our results show that under these conditions rolB greatly perturbs the expression of some chaperone-type proteins such as heat-shock proteins and cyclophilins. Heat-shock proteins of the DnaK subfamily were overexpressed in rolB-transformed calli, whereas the abundance of cyclophilins, members of the closely related single-domain cyclophilin family was decreased. Real-time PCR analysis of corresponding genes confirmed the reliability of proteomics data because gene expression correlated well with the expression of proteins. Bioinformatics analysis indicates that rolB can potentially affect several levels of signaling protein modules, including effector-triggered immunity (via the RPM1-RPS2 signaling module), the miRNA processing machinery, auxin and cytokinin signaling, the calcium signaling system and secondary metabolism.

Highlights

Decades-long study of plant-Agrobacterium interactions and T-DNA oncogene function has revealed very complex behavior of these systems and a sophisticated mechanism of pathogenesis
Expression of rolB in AtB-2 callus line was tested by Quantitative real-time PCR (qPCR) before proteomic analysis
Total protein fractions were isolated from Arabidopsis thaliana vector control and rolB-transgenic callus cultures as described in Materials and Methods

Summary

Introduction

Decades-long study of plant-Agrobacterium interactions and T-DNA oncogene function has revealed very complex behavior of these systems and a sophisticated mechanism of pathogenesis. Heat-shock 70-kDa proteins 6 and 7 (Hsp[] and Hsp70-7), Hsp90-5, 20-kDa chaperonin (Cpn10) and chaperonin 60 subunit α1 were activated in rolB-expressing Arabidopsis cells (Table 1). These interactions explain recent data indicating the active involvement of rolB in the modulation of expression of core components of the miRNA processing machinery, including SERRATE and AGO156.

Results

Conclusion