Boron nutrition of cultured tobacco BY-2 cells. VII. Rapid induction of metabolic dysfunction in cells deprived of boron as revealed by microarray analysis

In plants, boron (B) 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 catastrophe has not been well understood. In this study, we investigated the temporal changes in transcript profiles of B-deprived cultured tobacco (Nicotiana tabacum L.) BY-2 cells using cDNA microarray. The results suggest that the cells deprived of B up-regulated their antioxidative defense system to cope with the stress condition. However, the adaptive responses seemed to have declined within the first 12 h of deprivation. Tetrazolium reducing activity of B-deprived cells was lower than that of control cells at 12 h. These results together suggest that cellular function in B-deprived cells was seriously damaged as early as 12 h after deprivation. The rapidity of the onset of B deprivation-induced damages suggests the importance of the pectic network covalently cross-linked with B.