Salt affects plant Cd-stress responses by modulating growth and Cd accumulation.
Cadmium contamination is a serious environmental problem for modern agriculture and human health. Salinity affects plant growth and development, and interactions between salt and cadmium have been reported. However, the molecular mechanisms of salinity-cadmium interactions are not fully understood. Here, we show that a low concentration of salt alleviates Cd-induced growth inhibition and increases Cd accumulation in Arabidopsis thaliana. Supplementation with low concentrations of salt reduced the reactive oxygen species level in Cd-stressed roots by increasing the contents of proline and glutathione and down-regulating the expression of RCD1, thereby protecting the plasma membrane integrity of roots under cadmium stress. Salt supplementation substantially reduces the Cd-induced elevation of IAA oxidase activity, thereby maintaining auxin levels in Cd-stressed plants, as indicated by DR5::GUS expression. Salt supply increased Cd absorption in roots and increased Cd accumulation in leaves, implying that salt enhances both Cd uptake in roots and the root-to-shoot translocation of Cd. The elevated Cd accumulation in plants in response to salt was found to be correlated with the elevated levels of phytochelatin the expression of heavy metal transporters AtHMA1-4, especially AtHMA4. Salt alleviated growth inhibition caused by Cd and increased Cd accumulation also was observed in Cd accumulator Solanum nigrum.
Xu
Jin
J
Key Laboratory of Agricultural Water Resources, Center for Agricultural Resources, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 286 Huaizhong Road, 050021 Shijiazhuang, Hebei, China. xujin@sjziam.ac.cn
Yin
Hengxia
H
Liu
Xiaojing
X
Li
Xia
X
D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D002104:Cadmium / Q000378:metabolism* / Q000633:toxicity*; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005978:Glutathione / Q000378:metabolism; D010544:Peroxidases / Q000378:metabolism; D054811:Phytochelatins / Q000378:metabolism; D011392:Proline / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology*; D032324:Solanum nigrum / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D013312:Stress, Physiological / Q000187:drug effects*
D029681:Arabidopsis Proteins; D017382:Reactive Oxygen Species; D002104:Cadmium; D012965:Sodium Chloride; D054811:Phytochelatins; D011392:Proline; C027929:indoleacetic acid oxidase; D010544:Peroxidases; D000251:Adenosine Triphosphatases; C477864:HMA4 protein, Arabidopsis; D005978:Glutathione