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Transcript and protein profiling analysis of OTA-induced cell death reveals the regulation of the toxicity response process in Arabidopsis thaliana.

Wang Y, Peng X, Xu W, Luo Y, Zhao W, Hao J, Liang Z, Zhang Y, Huang K - J. Exp. Bot. (2011)

Bottom Line: Thirdly, a concomitant persistence of compromised photosynthesis and photorespiration is indicative of a metabolic shift from a highly active to a weak state.Finally, the data revealed that ethylene, salicylic acid, jasmonic acid, and mitogen-activated protein kinase signalling molecules mediate the process of toxicity caused by OTA.Profiling analyses on Arabidopsis in response to OTA will provide new insights into signalling transduction that modulates the OTA phytotoxicity mechanism, facilitate mapping of regulatory networks, and extend the ability to improve OTA tolerance in Arabidopsis.

View Article: PubMed Central - PubMed

Affiliation: China Agricultural University, Beijing, People's Repulic of China.

ABSTRACT
Ochratoxin A (OTA) is a toxic isocoumarin derivative produced by various species of mould which mainly grow on grain, coffee, and nuts. Recent studies have suggested that OTA induces cell death in plants. To investigate possible mechanisms of OTA phytotoxicity, both digital gene expression (DGE) transcriptomic and two-dimensional electrophoresis proteomic analyses were used, through which 3118 genes and 23 proteins were identified as being up- or down-regulated at least 2-fold in Arabidopsis leaf in response to OTA treatment. First, exposure of excised Arabidopsis thaliana leaves to OTA rapidly causes the hypersensitive reponse, significantly accelerates the increase of reactive oxygen species and malondialdehyde, and enhances antioxidant enzyme defence responses and xenobiotic detoxification. Secondly, OTA stimulation causes dynamic changes in transcription factors and activates the membrane transport system dramatically. Thirdly, a concomitant persistence of compromised photosynthesis and photorespiration is indicative of a metabolic shift from a highly active to a weak state. Finally, the data revealed that ethylene, salicylic acid, jasmonic acid, and mitogen-activated protein kinase signalling molecules mediate the process of toxicity caused by OTA. Profiling analyses on Arabidopsis in response to OTA will provide new insights into signalling transduction that modulates the OTA phytotoxicity mechanism, facilitate mapping of regulatory networks, and extend the ability to improve OTA tolerance in Arabidopsis.

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(A) ROS content measured by H2DCFDA fluorescence (n=3). (B) Lipid peroxidation. MDA content was determined as described in the Materials and methods (n=3). (C) The photosynthetic activity (Pn) was detected using the LI-6400XT photosynthetic system (n=3). OTA, 0.1 mM, 0.25 mM, 1 mM, Control, an equal volume of methanol.
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fig4: (A) ROS content measured by H2DCFDA fluorescence (n=3). (B) Lipid peroxidation. MDA content was determined as described in the Materials and methods (n=3). (C) The photosynthetic activity (Pn) was detected using the LI-6400XT photosynthetic system (n=3). OTA, 0.1 mM, 0.25 mM, 1 mM, Control, an equal volume of methanol.

Mentions: To verify further that a defence response took place and induced cell death under the treatment conditions, 4-week-old Arabidopsis leaves were treated with 0.25 mM OTA for 3, 8, and 24 h, and control leaves were treated with 0.122% methanol. Gene expression ratios relative to the control treatment are shown in Fig. 3. Several genes induced by OTA were characterized by potentiated expression of the salicylic acid-inducible marker gene PR1 and aminocyclopropane carboxylate synthase ACS6. These genes were up-regulated as the treatment time increased. The expression of respiratory burst oxidase homologue C (AtrbohC) and AtrbohD increased dramatically after 3 h and 24 h, respectively. The expression of the APX antioxidant gene was in accordance with the ROS level (Fig. 4A). There was a continuous increase in the ROS content with the increase of OTA concentration. The application of OTA to excised A. thaliana leaves significantly accelerated the increase in MDA (Fig. 4B).


Transcript and protein profiling analysis of OTA-induced cell death reveals the regulation of the toxicity response process in Arabidopsis thaliana.

Wang Y, Peng X, Xu W, Luo Y, Zhao W, Hao J, Liang Z, Zhang Y, Huang K - J. Exp. Bot. (2011)

(A) ROS content measured by H2DCFDA fluorescence (n=3). (B) Lipid peroxidation. MDA content was determined as described in the Materials and methods (n=3). (C) The photosynthetic activity (Pn) was detected using the LI-6400XT photosynthetic system (n=3). OTA, 0.1 mM, 0.25 mM, 1 mM, Control, an equal volume of methanol.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3295405&req=5

fig4: (A) ROS content measured by H2DCFDA fluorescence (n=3). (B) Lipid peroxidation. MDA content was determined as described in the Materials and methods (n=3). (C) The photosynthetic activity (Pn) was detected using the LI-6400XT photosynthetic system (n=3). OTA, 0.1 mM, 0.25 mM, 1 mM, Control, an equal volume of methanol.
Mentions: To verify further that a defence response took place and induced cell death under the treatment conditions, 4-week-old Arabidopsis leaves were treated with 0.25 mM OTA for 3, 8, and 24 h, and control leaves were treated with 0.122% methanol. Gene expression ratios relative to the control treatment are shown in Fig. 3. Several genes induced by OTA were characterized by potentiated expression of the salicylic acid-inducible marker gene PR1 and aminocyclopropane carboxylate synthase ACS6. These genes were up-regulated as the treatment time increased. The expression of respiratory burst oxidase homologue C (AtrbohC) and AtrbohD increased dramatically after 3 h and 24 h, respectively. The expression of the APX antioxidant gene was in accordance with the ROS level (Fig. 4A). There was a continuous increase in the ROS content with the increase of OTA concentration. The application of OTA to excised A. thaliana leaves significantly accelerated the increase in MDA (Fig. 4B).

Bottom Line: Thirdly, a concomitant persistence of compromised photosynthesis and photorespiration is indicative of a metabolic shift from a highly active to a weak state.Finally, the data revealed that ethylene, salicylic acid, jasmonic acid, and mitogen-activated protein kinase signalling molecules mediate the process of toxicity caused by OTA.Profiling analyses on Arabidopsis in response to OTA will provide new insights into signalling transduction that modulates the OTA phytotoxicity mechanism, facilitate mapping of regulatory networks, and extend the ability to improve OTA tolerance in Arabidopsis.

View Article: PubMed Central - PubMed

Affiliation: China Agricultural University, Beijing, People's Repulic of China.

ABSTRACT
Ochratoxin A (OTA) is a toxic isocoumarin derivative produced by various species of mould which mainly grow on grain, coffee, and nuts. Recent studies have suggested that OTA induces cell death in plants. To investigate possible mechanisms of OTA phytotoxicity, both digital gene expression (DGE) transcriptomic and two-dimensional electrophoresis proteomic analyses were used, through which 3118 genes and 23 proteins were identified as being up- or down-regulated at least 2-fold in Arabidopsis leaf in response to OTA treatment. First, exposure of excised Arabidopsis thaliana leaves to OTA rapidly causes the hypersensitive reponse, significantly accelerates the increase of reactive oxygen species and malondialdehyde, and enhances antioxidant enzyme defence responses and xenobiotic detoxification. Secondly, OTA stimulation causes dynamic changes in transcription factors and activates the membrane transport system dramatically. Thirdly, a concomitant persistence of compromised photosynthesis and photorespiration is indicative of a metabolic shift from a highly active to a weak state. Finally, the data revealed that ethylene, salicylic acid, jasmonic acid, and mitogen-activated protein kinase signalling molecules mediate the process of toxicity caused by OTA. Profiling analyses on Arabidopsis in response to OTA will provide new insights into signalling transduction that modulates the OTA phytotoxicity mechanism, facilitate mapping of regulatory networks, and extend the ability to improve OTA tolerance in Arabidopsis.

Show MeSH
Related in: MedlinePlus