Clathrin regulates blue light‐triggered lateral auxin distribution and hypocotyl phototropism in Arabidopsis |
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| Authors: | Xu Yan Chao Wang Qingmei Wang Jianzhong Liu Muyuan Zhu Sebastian Y Bednarek Jian Xu Jianwei Pan |
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| Affiliation: | 1. College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, China;2. Institute of Genetics, Key Laboratory for Cell and Gene Engineering of Zhejiang Province, College of Life Sciences, Zhejiang University, Hangzhou, China;3. Department of Biochemistry, University of Wisconsin – Madison, Madison, WI, USA;4. Department of Biological Sciences and NUS Centre for BioImaging Sciences, National University of Singapore, 14 Science Drive 4, Singapore |
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| Abstract: | Phototropism is the process by which plants grow towards light in order to maximize the capture of light for photosynthesis, which is particularly important for germinating seedlings. In Arabidopsis, hypocotyl phototropism is predominantly triggered by blue light (BL), which has a profound effect on the establishment of asymmetric auxin distribution, essential for hypocotyl phototropism. Two auxin efflux transporters ATP‐binding cassette B19 (ABCB19) and PIN‐formed 3 (PIN3) are known to mediate the effect of BL on auxin distribution in the hypocotyl, but the details for how BL triggers PIN3 lateralization remain poorly understood. Here, we report a critical role for clathrin in BL‐triggered, PIN3‐mediated asymmetric auxin distribution in hypocotyl phototropism. We show that unilateral BL induces relocalization of clathrin in the hypocotyl. Loss of clathrin light chain 2 (CLC2) and CLC3 affects endocytosis and lateral distribution of PIN3 thereby impairing BL‐triggered establishment of asymmetric auxin distribution and consequently, phototropic bending. Conversely, auxin efflux inhibitors N‐1‐naphthylphthalamic acid and 2,3,5‐triiodobenzoic acid affect BL‐induced relocalization of clathrin, endocytosis and lateralization of PIN3 as well as asymmetric distribution of auxin. These results together demonstrate an important interplay between auxin and clathrin function that dynamically regulates BL‐triggered hypocotyl phototropism in Arabidopsis. |
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| Keywords: | asymmetric auxin distribution endocytosis PIN3 efflux transporter |
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