title: Disruption of microtubules in plants suppresses macroautophagy and triggers starch excess-associated chloroplast autophagy.
abstract: Microtubules, the major components of cytoskeleton, are involved in various fundamental biological processes in plants. Recent studies in mammalian cells have revealed the importance of microtubule cytoskeleton in autophagy. However, little is known about the roles of microtubules in plant autophagy. Here, we found that ATG6 interacts with TUB8/β-tubulin 8 and colocalizes with microtubules in Nicotiana benthamiana. Disruption of microtubules by either silencing of tubulin genes or treatment with microtubule-depolymerizing agents in N. benthamiana reduces autophagosome formation during upregulation of nocturnal or oxidation-induced macroautophagy. Furthermore, a blockage of leaf starch degradation occurred in microtubule-disrupted cells and triggered a distinct ATG6-, ATG5- and ATG7-independent autophagic pathway termed starch excess-associated chloroplast autophagy (SEX chlorophagy) for clearance of dysfunctional chloroplasts. Our findings reveal that an intact microtubule network is important for efficient macroautophagy and leaf starch degradation.
authors.affiliation: a Center for Plant Biology ; Beijing , China.|b MOE Key Laboratory of Bioinformatics; School of Life Sciences; Tsinghua University ; Beijing , China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: a Center for Plant Biology ; Beijing , China.|b MOE Key Laboratory of Bioinformatics; School of Life Sciences; Tsinghua University ; Beijing , China.
authors.forename: Xiyin
authors.initials: X
authors.lastname: Zheng
authors.affiliation: a Center for Plant Biology ; Beijing , China.|b MOE Key Laboratory of Bioinformatics; School of Life Sciences; Tsinghua University ; Beijing , China.
authors.forename: Bingjie
authors.initials: B
authors.lastname: Yu
authors.affiliation: a Center for Plant Biology ; Beijing , China.|b MOE Key Laboratory of Bioinformatics; School of Life Sciences; Tsinghua University ; Beijing , China.
authors.forename: Shaojie
authors.initials: S
authors.lastname: Han
authors.affiliation: a Center for Plant Biology ; Beijing , China.
authors.forename: Jiangbo
authors.initials: J
authors.lastname: Guo
authors.affiliation: b MOE Key Laboratory of Bioinformatics; School of Life Sciences; Tsinghua University ; Beijing , China.
authors.forename: Haiping
authors.initials: H
authors.lastname: Tang
authors.affiliation: b MOE Key Laboratory of Bioinformatics; School of Life Sciences; Tsinghua University ; Beijing , China.
authors.forename: Alice Yunzi L
authors.initials: AY
authors.lastname: Yu
authors.affiliation: b MOE Key Laboratory of Bioinformatics; School of Life Sciences; Tsinghua University ; Beijing , China.
authors.forename: Haiteng
authors.initials: H
authors.lastname: Deng
authors.affiliation: c Research Center for Plant RNA Signaling; College of Life and Environmental Sciences; Hangzhou Normal University ; Hangzhou , China.
authors.forename: Yiguo
authors.initials: Y
authors.lastname: Hong
authors.affiliation: a Center for Plant Biology ; Beijing , China.|b MOE Key Laboratory of Bioinformatics; School of Life Sciences; Tsinghua University ; Beijing , China.
authors.forename: Yule
authors.initials: Y
authors.lastname: Liu
mesh_terms: D000818:Animals; D017360:Arabidopsis / Q000378:metabolism; D001343:Autophagy / Q000502:physiology*; D002736:Chloroplasts / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism; D013213:Starch / Q000378:metabolism*; D014404:Tubulin / Q000378:metabolism*
chemical_list: D014404:Tubulin; D013213:Starch
keywords: ATG6; chloroplast autophagy; leaf starch degradation; macroautophagy; microtubules; plants