title: Microtubule bundling plays a role in ethylene-mediated cortical microtubule reorientation in etiolated Arabidopsis hypocotyls.
abstract: The gaseous hormone ethylene is known to regulate plant growth under etiolated conditions (the 'triple response'). Although organization of cortical microtubules is essential for cell elongation, the underlying mechanisms that regulate microtubule organization by hormone signaling, including ethylene, are ambiguous. In the present study, we demonstrate that ethylene signaling participates in regulation of cortical microtubule reorientation. In particular, regulation of microtubule bundling is important for this process in etiolated hypocotyls. Time-lapse analysis indicated that selective stabilization of microtubule-bundling structures formed in various arrays is related to ethylene-mediated microtubule orientation. Bundling events and bundle growth lifetimes were significantly increased in oblique and longitudinal arrays, but decreased in transverse arrays in wild-type cells in response to ethylene. However, the effects of ethylene on microtubule bundling were partially suppressed in a microtubule-bundling protein WDL5 knockout mutant (wdl5-1). This study suggests that modulation of microtubule bundles that have formed in certain orientations plays a role in reorienting microtubule arrays in response to ethylene-mediated etiolated hypocotyl cell elongation.
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, Department of Plant Sciences, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
authors.forename: Qianqian
authors.initials: Q
authors.lastname: Ma
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, Department of Plant Sciences, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
authors.forename: Jingbo
authors.initials: J
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, Department of Plant Sciences, College of Biological Sciences, China Agricultural University, Beijing 100193, China maotonglin@cau.edu.cn.
authors.forename: Tonglin
authors.identifier: 0000-0003-3014-5350
authors.initials: T
authors.lastname: Mao
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics*; D005030:Ethylenes / Q000378:metabolism*; D055786:Gene Knockout Techniques; D018546:Hypocotyl / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000235:genetics*; D008870:Microtubules / Q000235:genetics* / Q000378:metabolism; D011485:Protein Binding
chemical_list: D029681:Arabidopsis Proteins; D005030:Ethylenes; D008869:Microtubule-Associated Proteins; C000621564:WDL5 protein, Arabidopsis; C036216:ethylene
keywords: Arabidopsis; Cortical microtubule; Ethylene; Hypocotyl growth; Orientation