Responses of tobacco BY-2 cells to boron deprivation

Boron (B) is an essential micronutrient for vascular plants. Boron works to build the cell wall structure by forming borate ester cross-links with pectin, and the deficiency of this element brings about oxidative damage and cell death. However, the process via which B deficiency leads to such serious damage has not been well understood. We investigated the temporal changes in metabolism of B-deprived cultured tobacco (Nicotiana tabacum) BY-2 cells by analyzing their gene expression using cDNA microarray. Three-day-old cells were deprived of B by washing with and transferred to B-free growth media ("-B" cells). Cells similarly treated with standard growth media were employed as a control for the effects of mechanical stress ("+B cells"). Cells were sampled at 1, 3, 6, 12 and 36 h after transfer to the B-free or standard media. Cells without washing treatment were also included in the analysis ("before-treatment cells"). Two independent sets of samples were analyzed (replicate 1 and 2).