Overexpression of an auxilin-like gene (F9E10.5) can suppress Al uptake in roots of Arabidopsis.
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 (approximately 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.
Ezaki
Bunichi
B
Research Institute for Bioresources, Okayama University, 2020-1, Chuou, Kurashiki, Okayama, 710-0046 Japan. bezaki@rib.okayama-u.ac.jp
Kiyohara
Hiroyuki
H
Matsumoto
Hideaki
H
Nakashima
Susumu
S
D000535:Aluminum / Q000378:metabolism*; D017360:Arabidopsis / Q000033:anatomy & histology / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D034021:Auxilins / Q000235:genetics / Q000378:metabolism*; D004705:Endocytosis / Q000235:genetics; D017136:Ion Transport / Q000235:genetics; D018517:Plant Roots / Q000033:anatomy & histology / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000378:metabolism
D029681:Arabidopsis Proteins; D034021:Auxilins; C518917:F9E10.5 protein, Arabidopsis; D000535:Aluminum