Abstract
Endoplasmic reticulum (ER) stress elicits a protective mechanism called unfolded protein response (UPR) to maintain cellular homeostasis, which can be regulated by defence hormones. In this study, the physiological role of jasmonic acid (JA) in ER stress and UPR signalling has been investigated in intact leaves of tomato plants. Exogenous JA treatments not only induced the transcript accumulation of UPR marker gene SlBiP but also elevated transcript levels of SlIRE1 and SlbZIP60. By the application of JA signalling mutant jai1 plants, the role of JA in ER stress sensing and signalling was further investigated. Treatment with tunicamycin (Tm), the inhibitor of N-glycosylation of secreted glycoproteins, increased the transcript levels of SlBiP. Interestingly, SlIRE1a and SlIRE1b were significantly lower in jai1. In contrast, the transcript accumulation of Bax Inhibitor-1 (SlBI1) and SlbZIP60 was higher in jai1. To evaluate how a chemical chaperone modulates Tm-induced ER stress, plants were treated with sodium 4-phenylbutyrate, which also decreased the Tm-induced increase in SlBiP, SlIRE1a, and SlBI1 transcripts. In addition, it was found that changes in hydrogen peroxide content, proteasomal activity, and lipid peroxidation induced by Tm is regulated by JA, while nitric oxide was not involved in ER stress and UPR signalling in leaves of tomato.
Highlights
A wide range of biotic and abiotic stress factors can disrupt the protein-folding capacity and the transport balance of the endoplasmic reticulum (ER), which results in the accumulation of misfolded or unfolded proteins in the lumen of ER and induces ER stress in plants [1,2,3,4]
Based on the investigation in Arabidopsis, both proteins are anchored to the ER membrane by interactions with BiP, which is an ER chaperone under control condition. bZIP28 is activated through the stress-induced accumulation of unfolded proteins in the ER lumen
The potential physiological role of jasmonic acid (JA) in ER stress sensing and unfolded protein response (UPR) was investigated the first time in jai1 plants which are defective in JA signalling
Summary
A wide range of biotic and abiotic stress factors can disrupt the protein-folding capacity and the transport balance of the endoplasmic reticulum (ER), which results in the accumulation of misfolded or unfolded proteins in the lumen of ER and induces ER stress in plants [1,2,3,4]. BAG7 is released from the ER membrane by an unknown protease; it is sumoylated and enters the nucleus, where it interacts with WRKY29 transcription factor and regulates the expression of various chaperone proteins to mitigate ER stress in Arabidopsis [25]. Another TF, the plant-specific NAM, ATAF, and CUC (NACs) TFs (e.g., NAC062 and NAC089) have been recently described as important regulators of ER stress responses that undergo proteolytic cleavage and translocation to the nucleus to promote the transcription of UPR or PCD genes in Arabidopsis [2,4]. The investigation of ER stress and UPR in cultivated plants could have great importance under diverse biotic and abiotic stress conditions from the agricultural aspect
Sign-in/Register to view highlights & summary 
Published Version (
Free)
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.
