Possible involvement of ploidy in tolerance to boron deficiency in Arabidopsis thaliana

Abstract

Boron is an essential nutrient for plant growth and reproduction. To identify a novel genetic mechanism which contributes to plant tolerance to nutrient deficiency, we screened Arabidopsis thaliana mutants for those tolerant to nutrient deficiencies. One of the isolated lines was tolerant to boron deficiency. This line was designated as LoBT1. From morphological characteristics and ploidy analysis, LoBT1 was found to be tetraploid, although the original screening population was diploid. Because LoBT1 is most likely to be created by the spontaneous duplication of the same diploid genome, LoBT1 is 'autotetraploid'. Independently isolated autotetraploid A. thaliana lines which were obtained from the ABRC stock center were also tolerant to boron deficiency, showing that autotetraploidization generally improves tolerance to boron deficiency. Our results represent the first demonstration that autopolyploidization can improve tolerance to environmental stress. Because the clear tolerance was observed under a model system, our observation offers considerable resources to analyze autotetraploid tolerance to environmental stress in more details. © 2010 The Japanese Society for Plant Cell and Molecular Biology.