Redox balance, metabolic fingerprint and physiological characterization in contrasting North East Indian rice for Aluminum stress tolerance

Abstract

Aluminum (Al) toxicity is a serious problem for rice crop productivity in acidic soils worldwide. The present work was conducted to look out for the alteration in ROS homeostasis; metabolic fingerprint; and morphology in two contrasting Indica rice cultivars of North East India (NE India) to Al toxicity. Al stress led to excess accumulation of ROS (H 2 O 2 and O 2 − ), and this in turn induced ROS mediated cellular damage, as indicated by lipid peroxidation both qualitatively as well as quantitatively. This excessive ROS production also led to significant reduction in chlorophyll content and stomatal conductance. This was followed by the loss of photosynthetic efficiency as detected by chlorophyll fluorescence. This excessive damage due to ROS prompted us to check the anti-oxidative machinery. Antioxidants, especially enzymes (SOD, APX, POX, GR, CAT, DHAR, MDHAR) are very important players in maintenance of ROS homeostasis. In tolerant variety Disang, higher activity of these enzymes and vice versa in sensitive variety, was observed in response to Al treatment. The non-enzymatic antioxidants (proline, ascorbate and glutathione) also showed similar trend. Though the tolerant variety showed strong anti-oxidative machinery, it was unable to completely nullify the stress experienced by the seedlings. Organic acids are also important players in detoxification of Al stress through efflux in the rhizosphere. In tolerant genotype, citrate exudate was found to be more when compared to sensitive genotypes on exposure to high dose of Al. This is supported by higher abundance of FRDL4, a citrate transporter. Not only FRDL4, other stakeholders for Al stress response like ART1 and ALS1 depicted prominent transcript abundance in the tolerant variety. In conclusion, through this study detailed physiological and metabolic characterisation of two contrasting Indica rice varieties Disang and Joymati, native to NE India for Al tolerance was performed for the very first time.

Antioxidant responses against aluminum metal stress in Geitlerinema amphibium

“…We marked an enhanced GPX expression upon induction of stress which is in the line reported in several higher plant species [2]. Further SOD-mediated catalyses for dismutation reaction detoxify the cellular upset [3,5]. Our study is in the path of similar finding reported above.…”

Oxidative Stress-Induced Alteration of Plant Central Metabolism

“…Although most studies have pointed to the suppression of TCA cycle activity, the protective role of TCA cycle metabolites under oxidative stress conditions has been also discussed. For example, the role of malate in the induction of protective antioxidant defense was demonstrated in green algae Scenedesmus obliquus and banana fruits [ 97 , 98 ], and citrate presence in the exudate of aluminum-tolerant Indica rice cultivars was shown to contribute to the tolerance of aluminum-induced oxidative stress [ 99 ].…”

“…Proline, a general stress response metabolite associated with chloroplasts and photosynthesis [ 8 ], was reported to decrease in Arabidopsis cell culture treated with H 2 O 2 [ 24 ], but increased in roots experiencing oxidative stress [ 25 , 28 ]. Oxidative stress resulting from aluminum toxicity was accompanied by a significant increase in proline in aluminum-tolerant rice cultivars [ 99 ]. The accumulation of proline under oxidative stress conditions and its role in the maintenance of redox balance have been demonstrated, although the ROS-scavenging ability of proline is still debated [ 117 , 118 ].…”

“…Oryza sativa suspension cells menadione treatment decrease in abundance [14] Triticum aestivum L. chlorinated organophosphate esters-induced oxidative stress increase in abundance [29] heterotrophic Arabidopsis cells H 2 O 2 treatment decrease in abundance [24] Arabidopsis thaliana roots menadione treatment transient decrease followed by increase [25,28] Arabidopsis thaliana methyl viologen treatment increase in abundance [17] Oryza sativa Al-induced oxidative stress presence in exudate, improves stress-tolerance [99] aconitate Oryza sativa suspension cells menadione treatment decrease in abundance [14] Triticum aestivum L. chlorinated organophosphate esters-induced oxidative stress increase in abundance [29] Arabidopsis thaliana methyl viologen treatment increase in abundance [17] isocitrate Oryza sativa suspension cells menadione treatment decrease in abundance [14] heterotrophic Arabidopsis cells menadione treatment decrease in abundance and/or formation [9] 2-oxo-glutarate…”

“…Arabidopsis thaliana roots menadione treatment decrease in abundance [25,28] Oryza sativa suspension cells menadione treatment decrease in abundance [14] Arabidopsis thaliana, cat2 mutant catalase-deficiency increase in abundance in leaves [112] Arabidopsis thaliana, vtc1 mutant UV-B-induced oxidative stress increase in abundance [114] Gln Arabidopsis thaliana UV-B-induced oxidative stress increase in abundance [115] Arg Oryza sativa suspension cells menadione treatment increase in abundance [14] GABA Arabidopsis thaliana roots menadione treatment increase in abundance [28] Triticum aestivum L. chlorinated organophosphate esters-induced oxidative stress increase in abundance [29] Oryza sativa suspension cells menadione treatment decrease in abundance [14] Arabidopsis thaliana elicitor-induced ROS burst priming effect [116] Pro Zea mays drought-induced oxidative stress accumulation in xylem sap [101] heterotrophic Arabidopsis cells H 2 O 2 treatment decrease in abundance [24] Arabidopsis thaliana roots menadione treatment increase in abundance [25,28] Oryza sativa suspension cells menadione treatment decrease in abundance [14] Ocimum basilicum treatment with cobalt nitrate increase in shoots [113] Oryza sativa Al-induced oxidative stress increase in abundance [99] Ornithine Arabidopsis thaliana roots menadione treatment transient increase [28] Citrulline in vitro -ROS-scavenging activity [119] Ala…”