Role of LOTR1 in nutrient transport through organization of spatial distribution of root endodermal barriers

Li, Baohai and Kamiya, Takehiro and Kalmbach, Lothar and Yamagami, Mutsumi and Yamaguchi, Katsushi and Shigenobu, Shuji and Sawa, Shinichiro and Danku, John M.C. and Salt, David E. and Geldner, Niko and Fujiwara, Toru (2017) Role of LOTR1 in nutrient transport through organization of spatial distribution of root endodermal barriers. Current Biology, 27 (5). pp. 758-765. ISSN 0960-9822

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Abstract

The formation of Casparian strips and suberin lamellae at the endodermis limits the free diffusion of nutrients and harmful substances via the apoplastic space between the soil solution and the stele in roots [1–3]. Casparian strips are ring-like lignin polymers deposited in the middle of anticlinal cellwalls between endodermal cells and fill the gap between them [4–6]. Suberin lamellae are glycerolipid polymers covering the endodermal cells and likely function as a barrier to limit transmembrane movement of apoplastic solutes into the endodermal cells [7, 8].However, the current knowledge on the formation of these two distinct endodermal barriers and their regulatory role in nutrient transport is still limited. Here, we identify an uncharacterized gene,LOTR1, essential for Casparian strip formation in Arabidopsis thaliana. The lotr1 mutants display altered localization of CASP1, an essential protein for Casparian strip formation [9], disrupted Casparian strips, ectopic suberization of endodermal cells, and low accumulation of shoot calcium (Ca). Degradation by expression of a suberin-degrading enzyme in the mutants revealed that the ectopic suberization at the endodermal cells limits Ca transport through the transmembrane pathway, thereby causing reduced Ca delivery to the shoot. Moreover, analysis of the mutants showed that suberin lamellae function as an apoplastic diffusion barrier to the stele at sites of lateral root emergence where Casparian strips are disrupted. Our findings suggest that the transmembrane pathway through unsuberized endodermal cells, rather than the sites of lateral root emergence,mediates the transport of apoplastic substances such as Ca into the xylem.

Item Type: Article
Keywords: Casparian strip; suberin; apoplast; transmembrane pathway; lateral root; cell wall; calcium transport
Schools/Departments: University of Nottingham, UK > Faculty of Science > School of Biosciences > Division of Plant and Crop Sciences
Identification Number: 10.1016/j.cub.2017.01.030
Depositing User: Eprints, Support
Date Deposited: 26 May 2017 10:13
Last Modified: 04 Jun 2017 03:54
URI: http://eprints.nottingham.ac.uk/id/eprint/43244

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