Comprehensive proteomic analysis of arsenic induced toxicity reveals the mechanism of multilevel coordination of efficient defense and energy metabolism in two Brassica napus cultivars

• Published in: Ecotoxicology and environmental safety 2021-01, Vol.208, p.111744, Article 111744
• Main Authors: Farooq, Muhammad Ahsan, Hong, Zheyuan, Islam, Faisal, Noor, Yamna, Hannan, Fakhir, Zhang, Yan, Ayyaz, Ahsan, Mwamba, Theodore M., Zhou, Weijun, Song, Wenjian
• Format: Article
• Language: English
• Subjects: Antioxidants; Arsenic; Arsenic - metabolism; Arsenic - toxicity; Brassica napus; Brassica napus - drug effects; Energy Metabolism; Gene Expression Regulation, Plant; iTRAQ proteomics; Plant Proteins - metabolism; Proteome - metabolism; Proteomics - methods; Secondary metabolites
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2020.111744

Arsenic (As) a non-essential element is of particular concern with respect to harmful effects on plant metabolism. While extensive studies have been conducted on the physiological responses of plants to increase As concentrations, however, molecular differences elucidating species-specific changes remain largely unknown. In the present experiment, two oilseed Brassica napus (B. napus) cultivars, ZS758 and ZD622, were treated by elevated As concentration. Their responses to the As stress have been investigated through pulse amplitude modulated fluorometer and isobaric tags based proteomic (iTRAQ) analysis. The chlorophyll fluorescence attributes showed that As stress significantly decrease the photochemical efficiency of photosystem II (PSII) and photosystem I (PSI) as well as the comparatively closed stomata observed under scanning electron microscopy (SEM). In this study, 65 proteins displayed increased abundance and 52 down-regulated were found in the control vs As comparison in cultivar ZS758, while 44 up and 67 down-regulated proteins were found in the control vs As comparison in ZD622. Metabolic pathways, followed by ribosome and biosynthesis of secondary metabolites were the dominant functional annotation categories among the differentially expressed protein (DEPs). Many genes involved in primary metabolism, stress and defense were found to be As-responsive DEPs and/or DEPs between these two cultivars. Based on these results, a schematic description of key processes involved in As tolerance in ZS758 and ZD622 is proposed, which suggests that higher tolerance in ZS758 depends on a multilevel coordination of efficient defense and energy metabolism. Real-time quantitative PCR supported the expression patterns of several genes encoding a protein similar to their corresponding DEPs. In addition, these findings could shed light in unraveling the molecular mechanisms of B. napus exposed to As stress and provide or improve essential understandings in the development of advanced B. napus cultivars against As resistance. •Differential response adaptation of two B. napus cultivars to As stress.•Altered activities and expression level of antioxidants enzymes.•Stressed plants have reduced level of photosynthetic activity.•Unlike ZD622, ZS758 preferentially showed better tolerance to As stress.