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Boron deprivation immediately causes cell death in growing roots of Arabidopsis thaliana (L.) Heynh.

Oiwa, Yuki, Kitayama, Kahori, Kobayashi, Masaru, Matoh, Toru
Soil science and plant nutrition 2013 v.59 no.4 pp. 621-627
Arabidopsis thaliana, Nicotiana tabacum, boron, calcium, cell death, cell walls, crosslinking, culture media, death, genes, magnesium, pectins, potassium, reactive oxygen species, root growth, roots, stress response, tobacco
Boron (B) is essential for the correct formation of cell wall structure because it is a component of borate-ester cross-links in pectin. Previously, we showed that removal of B from the culture medium immediately induced stress responses in suspension-cultured tobacco (Nicotiana tabacum L.) cells, but the mechanism by which cells exhibit such rapid responses remained unclear. In this study, we characterized the early responses of Arabidopsis thaliana (L.) Heynh. to B deprivation. Deprivation of B for 1 h caused cell death specifically in the root elongation zone. Reactive oxygen species accumulated in the same region, suggesting that the death was caused by oxidative damage. The B-deprivation treatment also induced the expressions of stress-responsive genes within 1 h. These results demonstrated that A. thaliana immediately senses and responds to the removal of B from the external medium. Similar responses were induced by calcium deprivation but not magnesium or potassium deprivation, suggesting that the failure of cross-linking in pectin molecules in growing cells triggers these rapid responses.