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The role of chloroplast protein remodeling in stress responses and shaping of the plant peptidome

Researchers of the Laboratory of plant functional genomics and proteomics, IBCh RAS, in collaboration with Laboratory of molecular basis of plant stress resistance, IBCh RAS, and James Hutton Institute (United Kingdom) published a review article in the international peer-reviewed scientific journal New Phytologist (IF = 7.29). This review “The role of chloroplast protein remodeling in stress responses and shaping of the plant peptidome” is focused on processes of reorganization of the chloroplast proteome under stress conditions and on the roles of bioactive peptides generated from chloroplast proteins.

Peptides are often considered as merely breakdown products of protein degradation, however recent evidence suggests that such peptides are biologically active and involved in various regulation processes. One of the main scientific interests of laboratory of plant functional genomics and proteomics is focused on the identification of novel biologically active peptides (Fesenko et al., 2019; Lyapina et al., 2019; Fesenko et al., 2019; Filippova et al., 2018; Khazigaleeva et al., 2017; Fesenko et al., 2016; Fesenko et al., 2015). As such, researchers of this laboratory have recently revealed that endogenous peptides generated from chloroplast proteins constitute not only substantial part of the plant intracellular peptidome, but are also secreted into the extracellular space. This observation has inspired the authors to write a literature review focused on chloroplast protein degradation and on the roles of its bioactive products.

Chloroplast proteome comprises around 2000-3000 proteins, only 100 of which are encoded by chloroplast genome, while the rest of the proteins are encoded by nuclear genome, translated in the cytoplasm and are then transported into the chloroplasts. Moreover, chloroplast proteins are constantly replaced in plant cells. Remodeling of the chloroplast proteome is carried out by a complex system of proteases under various conditions. Also, chloroplasts can undergo complete or partial degradation, which leads to the generation of peptides. Proteolysis of some chloroplast proteins is needed for retrograde signaling under high light intensities and reactive oxygen species formation. Cryptic peptides, inceptins, are generated upon degradation of H+-ATPase under biotic stress conditions and trigger immune responses in plant cells. Moreover, treatment with stress phytohormone, methyl jasmonate, leads to generation of antimicrobial peptides from chloroplast proteins. Thus, peptides cleaved out from chloroplast proteins play important roles in maintenance of plant overall fitness and constitute important but poorly studied part of the plant peptidome. All of these and more can be found in the article by Mamaeva et al., 2020.

*This work was supported by the Government of Russian Federation Grant No. 14.W03.31.0003

april 29, 2020