Proteome Changes Reveal the Protective Roles of Exogenous Citric Acid in Alleviating Cu Toxicity in Brassica napus L.

Abstract

Citric acid (CA), as an organic chelator, plays a vital role in alleviating copper (Cu) stress-mediated oxidative damage, wherein a number of molecular mechanisms alter in plants. However, it remains largely unknown how CA regulates differentially abundant proteins (DAPs) in response to Cu stress in Brassica napus L. In the present study, we aimed to investigate the proteome changes in the leaves of B. L. seedlings in response to CA-mediated alleviation of Cu stress. Exposure of 21-day-old seedlings to Cu (25 and 50 μM) and CA (1.0 mM) for 7 days exhibited a dramatic inhibition of overall growth and considerable increase in the enzymatic activities (POD, SOD, CAT). Using a label-free proteome approach, a total of 6345 proteins were identified in differentially treated leaves, from which 426 proteins were differentially expressed among the treatment groups. Gene ontology (GO) and KEGG pathways analysis revealed that most of the differential abundance proteins were found to be involved in energy and carbohydrate metabolism, photosynthesis, protein metabolism, stress and defense, metal detoxification, and cell wall reorganization. Our results suggest that the downregulation of chlorophyll biosynthetic proteins involved in photosynthesis were consistent with reduced chlorophyll content. The increased abundance of proteins involved in stress and defense indicates that these DAPs might provide significant insights into the adaptation of Brassica seedlings to Cu stress. The abundances of key proteins were further verified by monitoring the mRNA expression level of the respective transcripts. Taken together, these findings provide a potential molecular mechanism towards Cu stress tolerance and open a new route in accelerating the phytoextraction of Cu through exogenous application of CA in B. napus.

Label‐free proteomics approach reveals candidate proteins in rice (Oryza sativa L.) important for ACC deaminase producing bacteria‐mediated tolerance against salt stress

“…There was no difference in mRNA expression profiles between T1 and T3 in the case of DEAD‐box ATP‐dependent RNA helicase 56 expression profiles (Fig. 7E), which might be due to the post‐transcriptional and translational modifications occurring in plant cells that cannot be measured by qRT‐PCR (Ju et al ., 2021).…”

“…The number of proteins detected in each treatment of the current study was observed to be lower compared to previous studies that were conducted on different model plants such as Oryza sativa cv. indica (López‐Cristoffanini et al ., 2020), Brassica L. (Ju et al ., 2021) and Arabidopsis (Tang et al ., 2020). This can be due to the limited information about the characterized proteins present in the database while using non‐model crops (Buts et al ., 2014).…”

Photosynthetic Characteristics and Chloroplast Ultrastructure Responses of Citrus Leaves to Copper Toxicity Induced by Bordeaux Mixture in Greenhouse

“…Antioxidant enzymes such as SOD, POD and CAT played pivotal roles in ROS scavenging, alleviating oxidative stress [ 49 ]. It was evidenced that Cu toxicity significantly upregulated the enzymatic activities of SOD, POD and CAT in Brassica napus leaves [ 50 ] and flax shoots [ 51 ]. In the present study, excessive Bm-treated C. grandis leaves had a remarkably higher POD and CAT enzymatic activity ( Figure 8 C,D) than the control.…”

Understanding the Proteomes of Plant Development and Stress Responses in Brassica Crops

“…Copper (Cu) is another metal that could cause toxicity when present in higher amounts in the soil; however, it is also one of the essential micronutrients required by the plants. To identify DAPs in B. napus under Cu toxicity by using a label-free proteome approach, 6345 proteins were detected in different treatment groups exposed to Cu and/or citric acid, and among these, 426 proteins were found to be differentially expressed . The pathways enriched by these DAPs included photosynthesis, metabolism of energy and carbohydrate, protein metabolism, detoxification of metals, stress and defense, and pathways related to cell wall reorganization.…”

“…To identify DAPs in B. napus under Cu toxicity by using a label-free proteome approach, 6345 proteins were detected in different treatment groups exposed to Cu and/or citric acid, and among these, 426 proteins were found to be differentially expressed. 136 The pathways enriched by these DAPs included photosynthesis, metabolism of energy and carbohydrate, protein metabolism, detoxification of metals, stress and defense, and pathways related to cell wall reorganization. The key upregulated proteins belonged to the family of glutathione Stransferase, ascorbate peroxidase, and carboxylase, while carbonic anhydrase and phosphoglycerate dehydrogenase were the key downregulated proteins.…”