The Physcomitrella patens chloroplast proteome changes in response to short-term stress

ABSTRACT: Plants often face more than one type of stress at a time, and how plants respond to combined stress factors is therefore of great interest. Here, we used protoplasts of the moss Physcomitrella patens as a model to study the effects of short-term combined stress on the chloroplast proteome. In this system, biotic stress is mimicked by exposure to cell wall-hydrolyzing enzymes, and abiotic stress is related to plasmolysis. We used SWATH-MS to perform label-free comparative quantitative proteomic analysis of the chloroplast proteome. Overall, we quantified 480 chloroplast proteins, 220 of which showed a more than 1.4-fold change in abundance in protoplasts. We additionally quantified 1422 chloroplast proteins using emPAI. We observed degradation of a significant portion of the chloroplast proteome during the first hour of stress. Electron-transport chain (ETC) components underwent the heaviest degradation, resulting in the decline of photosynthetic activity. We also compared the proteome changes to those in the transcriptional level of nuclear-encoded chloroplast genes. Globally, the levels of the quantified proteins and their corresponding mRNAs showed limited correlation. Genes involved in the biosynthesis of chlorophyll and components of the outer chloroplast membrane showed decreases in both transcript and protein abundance. However, proteins like dehydroascorbate reductase 1 and 2-cys peroxiredoxin B responsible for ROS detoxification increased in abundance. Further, genes such as thylakoid ascorbate peroxidase were induced at the transcriptional level but down-regulated at the proteomic level. Together, our results demonstrate that the initial chloroplast reaction to stress is due changes at the proteomic level.

INSTRUMENT(S): TripleTOF 5600, Q TRAP

ORGANISM(S): Physcomitrella Patens Subsp. Patens (moss)

TISSUE(S): Chloronema, Plant Cell, Protonema

SUBMITTER: Ivan Butenko  

LAB HEAD: Gleb Fisunov

PROVIDER: PXD005017 | Pride | 2016-12-23

REPOSITORIES: Pride