Overexpression of an auxilin-like gene (F9E10.5) can suppress Al uptake in roots of Arabidopsis

• Published in: Journal of experimental botany 2007-02, Vol.58 (3), p.497-506
• Main Authors: Ezaki, Bunichi, Kiyohara, Hiroyuki, Matsumoto, Hideaki, Nakashima, Susumu
• Format: Article
• Language: English
• Subjects: Activation-tagged mutant line; Al influx; aluminium (Al) resistance mechanism; Aluminum - metabolism; Arabidopsis - anatomy & histology; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Arabidopsis thaliana; auxilin-like protein; Auxilins - genetics; Auxilins - metabolism; Biological and medical sciences; endocytosis; Endocytosis - genetics; Fundamental and applied biological sciences. Psychology; Genes. Genome; Ion Transport - genetics; Molecular and cellular biology; Molecular genetics; oxidative stress; Plant Roots - anatomy & histology; Plant Roots - genetics; Plant Roots - metabolism; Plants, Genetically Modified - metabolism; root hair
• ISSN: 0022-0957; 1460-2431
• DOI: 10.1093/jxb/erl221

Plants resistant to aluminium (Al) stress were isolated from Arabidopsis thaliana enhancer-tagged mutant lines. Compared with the parental Col-7 control line, one of the resistant candidates, #355-2, showed a higher expression of the F9E10.5 gene (At1g75100) on chromosome 1, a lower Al content in whole roots, and a shorter root hair length (∼30%). Both Al influx and associated oxidative stress occurred in root hairs, as well as in root tips of Col-7; however, they were seen only in root tips of #355-2. Transgenic plants overexpressing the F9E10.5 gene showed a slightly higher Al resistance than their parental control line (Ler). The F9E10.5 gene encodes an auxilin-like protein related to the clathrin-uncoating process in endocytosis. Microscopic observation indicated that both Al ion influx and endocytosis activity were lower in root hair cells of the #355-2 line than in those of Col-7. These results suggested that overexpression of this auxilin-like protein inhibits endocytosis in root hair cells by a disturbance of the transport system as in animal cells shown previously. It was also suggested that a part of the Al influx occurred via endocytosis in root hair cells in Arabidopsis. The Al resistance in the #355-2 line may therefore be due to a lower Al uptake via endocytosis in the root hair region.