title: Characterization of tub4(P287L) , a β-tubulin mutant, revealed new aspects of microtubule regulation in shade.
abstract: When sun plants, such as Arabidopsis thaliana, are under canopy shade, elongation of stems/petioles will be induced as one of the most prominent responses. Plant hormones mediate the elongation growth. However, how environmental and hormonal signals are translated into cell expansion activity that leads to the elongation growth remains elusive. Through forward genetic study, we identified shade avoidance2 (sav2) mutant, which contains a P287L mutation in β-TUBULIN 4. Cortical microtubules (cMTs) play a key role in anisotropic cell growth. Hypocotyls of sav2 are wild type-like in white light, but are short and highly swollen in shade and dark. We showed that shade not only induces cMT rearrangement, but also affects cMT stability and dynamics of plus ends. Even though auxin and brassinosteroids are required for shade-induced hypocotyl elongation, they had little effect on shade-induced rearrangement of cMTs. Blocking auxin transport suppressed dark phenotypes of sav2, while overexpressing EB1b-GFP, a microtubule plus-end binding protein, rescued sav2 in both shade and dark, suggesting that tub4(P287L) represents a unique type of tubulin mutation that does not affect cMT function in supporting cell elongation, but may affect the ability of cMTs to respond properly to growth promoting stimuli.
authors.affiliation: School of Life Sciences, Xiamen Plant Genetics Key Laboratory, Xiamen University, Xiamen, 361102, China.|State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiamen, 361102, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Yu
authors.affiliation: School of Life Sciences, Xiamen Plant Genetics Key Laboratory, Xiamen University, Xiamen, 361102, China.|State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiamen, 361102, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Qiu
authors.affiliation: School of Life Sciences, Xiamen Plant Genetics Key Laboratory, Xiamen University, Xiamen, 361102, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
authors.affiliation: School of Life Sciences, Xiamen Plant Genetics Key Laboratory, Xiamen University, Xiamen, 361102, China.
authors.forename: Meiling
authors.initials: M
authors.lastname: Wang
authors.affiliation: School of Life Sciences, Xiamen Plant Genetics Key Laboratory, Xiamen University, Xiamen, 361102, China.
authors.forename: Yongli
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Howard Hughes Medical Institute, The Salk Institute for Biological Studies, La Jolla, California, 92037, USA.|Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, California, 92037, USA.
authors.forename: Joanne
authors.initials: J
authors.lastname: Chory
authors.affiliation: School of Life Sciences, Xiamen Plant Genetics Key Laboratory, Xiamen University, Xiamen, 361102, China.|State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiamen, 361102, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Tao
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D008870:Microtubules / Q000235:genetics* / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism; D014404:Tubulin / Q000235:genetics* / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D010937:Plant Growth Regulators; D014404:Tubulin
keywords: Arabidopsis; microtubules; plant hormones; shade