Abstract
Plants are able to synthesize all essential metabolites from minerals, water, and light to complete their life cycle. This plasticity comes at a high energy cost, and therefore, plants need to tightly allocate resources in order to control their economy. Being sessile, plants can only adapt to fluctuating environmental conditions, relying on quality control mechanisms. The remodeling of cellular components plays a crucial role, not only in response to stress, but also in normal plant development. Dynamic protein turnover is ensured through regulated protein synthesis and degradation processes. To effectively target a wide range of proteins for degradation, plants utilize two mechanistically-distinct, but largely complementary systems: the 26S proteasome and the autophagy. As both proteasomal- and autophagy-mediated protein degradation use ubiquitin as an essential signal of substrate recognition, they share ubiquitin conjugation machinery and downstream ubiquitin recognition modules. Recent progress has been made in understanding the cellular homeostasis of iron and sulfur metabolisms individually, and growing evidence indicates that complex crosstalk exists between iron and sulfur networks. In this review, we highlight the latest publications elucidating the role of selective protein degradation in the control of iron and sulfur metabolism during plant development, as well as environmental stresses.
Highlights
Because plants are sessile and often face biotic and abiotic stresses, including fluctuating availability of nutrients, drought, and diseases, their ability to thrive in a dynamic environment is a biochemical feat
TOR acts as a master regulator of cellular and developmental processes in response to a variety of TOR is active under nutrient-rich conditions, when it increases cell growth and translation whilst preventing autophagy, but it is inhibited during nutrient deficiency [119]
Plant responses to iron and sulfur deficiencies appear to be mediated by both transcriptional regulation and protein quality control via ubiquitination
Summary
Because plants are sessile and often face biotic and abiotic stresses, including fluctuating availability of nutrients, drought, and diseases, their ability to thrive in a dynamic environment is a biochemical feat. Arabidopsis contains nine highly-conserved ATG8 proteins that, after processing, coat the autophagosomal membranes and serve as a docking platform for autophagy receptors that selectively recognize and bind the cargo designated for degradation [29,31]. It was recently shown that iron limitation strongly reduced total sulfur content in both shoots and roots of tomato plants, leading to an increased transcription of sulfate transporters [6] These findings point to coregulation between the two pathways as one nutrient limitation affects the other’s uptake. We gathered examples of proteins involved in either iron or sulfur metabolism that are the targets of selective degradation Those proteins have to be removed after specific intra- or extra- cellular cues to reprogram plant metabolism and sustain homeostasis. There are ample examples of such proteins for iron metabolism, data for sulfur metabolism is rather scarce
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
