title: Calcium supplementation modulates arsenic-induced alterations and augments arsenic accumulation in callus cultures of Indian mustard (Brassica juncea (L.) Czern.).
abstract: In the present study, the effect of arsenate (AsV) exposure either alone or in combination with calcium (Ca) was investigated in callus cultures of Brassica juncea (L.) Czern. cv. Pusa Bold grown for a period up to 24 h. The AsV (250 μM) + Ca (10 mM) treatment resulted in a significantly higher level of As (464 μg g(-1) dry weight (DW)) than AsV without Ca (167 μg g(-1) DW) treatment at 24 h. Furthermore, AsV + Ca-treated calli had a higher percent of AsIII (24-47%) than calli subjected to AsV treatment (12-14%). Despite this, AsV + Ca-treated calli did not show any signs of hydrogen peroxide (H(2)O(2)) accumulation or cell death upon in vivo staining, while AsV-exposed calli had increased H(2)O(2), shrinkage of cytoplasmic contents, and cell death. Thus, AsV treatment induced oxidative stress, which in turn elicited a response of antioxidant enzymes and metabolites as compared with control and AsV + Ca treatment. The positive effects of Ca supplementation were also correlated to an increase in thiolic constituents', viz., cysteine, reduced glutathione, and glutathione reductase in AsV + Ca than in AsV treatment. An analysis of selected signaling related genes, e.g., mitogen-activated protein kinases (MAPK3 and MAPK6) and jasmonate ZIM-domain (JAZ3) suggested that AsV and AsV + Ca followed variable pathways to sense and signal the As stress. In AsV-alone treatment, jasmonate signaling was seemingly activated, while MAPK3 was not involved. In contrast, AsV + Ca treatment appeared to specifically inhibit jasmonate signaling and activate MAPK3. In conclusion, Ca supplementation may hold promise for achieving increased As accumulation in plants without compromising their tolerance.
authors: Functional Plant Biology Section, Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400 085, India.
authors: Archana Neeraj
authors: AN
authors: Rai
authors: Sudhakar
authors: S
authors: Srivastava
authors: Radhakrishna
authors: R
authors: Paladi
authors: Penna
authors: P
authors: Suprasanna
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D001149:Arsenates / Q000378:metabolism / Q000494:pharmacology*; D060387:Ascorbate Peroxidases / Q000378:metabolism; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology*; D002374:Catalase / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D046508:Culture Techniques; D003545:Cysteine / Q000378:metabolism; D003593:Cytoplasm / Q000187:drug effects / Q000378:metabolism; D020869:Gene Expression Profiling; D005978:Glutathione / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D009149:Mustard Plant / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011392:Proline / Q000378:metabolism; D015398:Signal Transduction; D012989:Soil Pollutants / Q000378:metabolism / Q000494:pharmacology*; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D000975:Antioxidants; D001149:Arsenates; D010940:Plant Proteins; D012989:Soil Pollutants; D011392:Proline; D006861:Hydrogen Peroxide; D060387:Ascorbate Peroxidases; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D005980:Glutathione Reductase; D005978:Glutathione; D003545:Cysteine; C025657:arsenic acid; D002118:Calcium