Disarrangement of actin filaments and Ca2+ gradient by CdCl2 alters cell wall construction in Arabidopsis thaliana root hairs by inhibiting vesicular trafficking

Cadmium toxicity

“…[24][25][26][27] Fan et al labeled the endocytic vesicles using the fluorescent membrane dye FM4-64 to observe whether cadmium treatment influenced endocytosis and vesicular transport in root hair cells. 15 Their time-lapse images of cadmium-treated root hairs showed that the FM dye staining pattern was obviously distinct from that of control cells, suggesting that membrane endocytosis and vesicular trafficking were perturbed during cadmium stress and this perturbation might result from the cadmium-induceddisruption of the "tracks" (actin filaments) for vesicle transport (Fig. 1).…”

“…14 Recently, the effect of cadmium on arrangement of actin filaments was studied in Arabidopsis. 15 Actin filaments were markedly disrupted depending on the cadmium concentration and the time of treatment in root hairs. Treatment with 5 mM cadmium destroyed the arrangement of actin filaments, changing them from a longitudinal to a transverse array.…”

“…18 However, Fan et al found that the cytoplasmic concentration of calcium decreased in cadmium-treated Arabidopsis root hairs. 15 Therefore it is possible that that cadmium might mimic calcium to activate actin filament-severing proteins and thus lead to actin filaments depolymerization. Calcium in the crystal structure of gelsolin, a calcium-dependent actin-severing protein, can be reportedly replaced by cadmium, indicating that cadmium can activate gelsolin for actin filament binding and severing.…”

“…41 The distribution of de-esterified and esterified pectins on the radical apex differed with different concentrations of cadmium, indicating that cadmium spatially modulates the synthesis and distribution of both pectins. 15 In addition, de-esterified pectins can bind with calcium by their carboxyl groups and thus increase stiffening of cell wall, which contribute to inhibition of cell expansion. Other polysaccharides and components in the cell wall such as cellulose, semi-cellulose and proteins also play a crucial role in metal binding and accumulation.…”

CsPDC-E1α, a novel pyruvate dehydrogenase complex E1α subunit gene from Camellia sinensis, is induced during cadmium inhibiting pollen tube growth

“…6) is consistent with these previous reports. Additionally, in Arabidopsis root tip mitochondria, exposure to high concentration of Cd caused swelling and altered morphology, degradation of internal membranes and loss of (Fan et al 2011). More importantly, the mitochondria were distributed in Lilium longiflorum and Nicotiana tabacum pollen tube tip throughout the subapical region and mixed with the vesicles of the tube apex under increased Cd concentrations (Sawidis 2008).…”