Difference in the distribution and speciation of cellular nickel between nickel-tolerant and non-tolerantNicotiana tabacumL. cv. BY-2 cells

Autor: Masaaki Yoshiba, Toshiaki Tadano, Eitaro Miwa, Yusuke Ichikawa, Kyoko Higuchi, Misa Saito, Akihiro Saito
Rok vydání: 2010
Předmět:
Zdroj: Plant, Cell & Environment. 33:174-187
ISSN: 1365-3040
0140-7791
DOI: 10.1111/j.1365-3040.2009.02068.x
Popis: To evaluate Ni dynamics at the subcellular level, the distribution and speciation of Ni were determined in wild-type (WT) and Ni-tolerant (NIT) tobacco BY-2 cell lines. When exposed to low but toxic levels of Ni, NIT cells were found to contain 2.5-fold more Ni (14% of whole-cell Ni values) in their cell walls than WT cells (6% of whole-cell Ni values). In addition to higher levels of Ni in the apoplast, a higher proportion (94%) of symplastic Ni was localized in the vacuoles of NIT cells than in the vacuoles of WT cells (81%). The concentration of cytosolic Ni in the NIT cells was significantly lower (18 nmol g(-1) FW) than that in the WT cells (85 nmol g(-1) FW). In silico simulation showed that 95% of vacuolar Ni was in the form of Ni-citrate complexes, and that free Ni(2+) was virtually absent in the NIT cells. On the other hand, the amount of free metal ions was markedly increased in WT cells because free citrate was depleted by chelation of Ni. A protoplast viability assay using BCECF-AM further demonstrated that the main mechanism that confers strong Ni tolerance was present in the symplast as opposed to the cell wall.
Databáze: OpenAIRE
Externí odkaz: