Role of overexpressed BOR4, a boron exporter,in tolerance to high level of boron in shoots |
| |
| Authors: | Kyoko Miwa Toru Fujiwara |
| |
| Institution: | 1. Creative Research Institution, Hokkaido University
, Kita-ku, Sapporo, 001-0021, Japan;2. Biotechnology Research Center, University of Tokyo
, Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan;3. Biotechnology Research Center, University of Tokyo
, Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan;4. Graduate School of Agricultural and Life Sciences, The University of Tokyo
, Tokyo, 113-8657, Japan;5. Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency
, Saitama 332-0012, Japan |
| |
| Abstract: | High boron (B) tolerance is an important trait for crop production in high-B soils. We previously reported that overexpression of BOR4, an Arabidopsis thaliana B exporter, conferred high B tolerance in A. thaliana. This improvement appeared to be mainly due to the decreased B concentrations in roots through BOR4-mediated exclusion of B. In the present study, we describe a novel role of overexpressed BOR4 in shoots for high B tolerance. We compared shoot growth of wild type A. thaliana and transgenic plants moderately overexpressing BOR4 in relation to B concentration in shoots. It was found that growths and chlorophyll accumulation of shoots containing similar levels of B are better in the transgenic plants than the wild type. This finding established that BOR4-overexpressing plants are more capable of expanding leaves and accumulating chlorophyll in the presence of high B in shoot tissues. BOR4-GFP was found to be localized to plasma membrane in leaf epidermis cells. We suggest that overexpressed BOR4 alters B distribution in leaves by exporting B from the cytoplasm to the apoplast, leading to enhancement of high B tolerance in shoots. |
| |
| Keywords: | apoplast Arabidopsis thaliana boron exporter boron tolerance transgenic plant |
|
|
