Wortmannin-induced vacuole fusion enhances amyloplast dynamics in Arabidopsiszigzag1hypocotyls

Abstract

HighlightThe highly restricted movement of amyloplasts in graviperceptive cells of zig-1 hypocotyls is overcome by wortmannin treatment, suggesting a physical association between amyloplasts and the vacuole.

The Vacuolar Protein Sorting-38 Subunit of the Arabidopsis Phosphatidylinositol-3-Kinase Complex Plays Critical Roles in Autophagy, Endosome Sorting, and Gravitropism

“…The meandering, wavy growth of vps38 roots (see Figure 3C ), along with the report that the PtdIn-3 kinase inhibitors LY294002 and wortmannin impair Arabidopsis gravitropism ( Joo et al, 2005 ; Jaillais et al, 2006 ; Alvarez et al, 2016 ), implicated VPS38 in gravity perception. As shown in Figure 10B , quantitation of this meander without reorienting the plants easily showed that vps38-1 and vps38-3 roots display a weaker gravity response as compared to WT or the VPS38-FLAG complementation lines.…”

“…In a similar fashion, mutations in the GRV2 protein important to vacuolar sorting also display dampened gravitropism ( Tamura et al, 2007 ; Silady et al, 2008 ). When connected with the prior observation that UNHINGED, which localizes to the TGN and prevacuolar compartments and regulates vesicle movements, also impacts auxin signaling ( Pahari et al, 2014 ) and that the zig-1 gravitropism mutant encoding the VTI11 SNARE protein is hypersensitive to wortmannin ( Alvarez et al, 2016 ), the links between PtdIn-3P, membrane trafficking, auxins, and root gravitropism become more obvious. Conversely, loss of VPS38 had only a slight effect on hypocotyl phototropism, but this dampened light response was complicated by the slowed hypocotyl elongation of the mutants.…”

“…It has long been appreciated that PtdIn-3P, and by inference its associated kinases, are important for eukaryotic membrane identity and vesicular trafficking ( Balla, 2013 ), but its exact roles in plants have remained largely enigmatic due to the lack of informative genetic tools for the sole known class-III PtdIn-3 kinase complex that generates this lipid ( Gerth et al, 2017 ; Noack and Jaillais, 2017 ). For example, while the PtdIn-3 kinase-selective inhibitors wortmannin and LY294002 have tentatively connected PtdIn-3P to various events ( Takatsuka et al, 2004 ; daSilva et al, 2005 ; Joo et al, 2005 ; Jaillais et al, 2006 ; Takáč et al, 2013 ; Fujimoto et al, 2015 ; Alvarez et al, 2016 ), the essential nature of the single Arabidopsis genes that encode the core VPS34, VPS15, and ATG6 (VPS30/Beclin1) subunits has stalled further investigations beyond its importance to pollen germination ( Fujiki et al, 2007 ; Qin et al, 2007 ; Harrison-Lowe and Olsen, 2008 ; Lee et al, 2008a , b ; Xu et al, 2011 ; Wang et al, 2012 ).…”

Transcriptome and metabolite analyses provide insights into zigzag-shaped stem formation in tea plants (Camellia sinensis)

“…It is well recognized that a zigzag-shaped inflorescence stem results from the mutation of zig (zigzag)/sgr4, which encodes VPS10 interacting 11 (VTI11), a Qb-SNARE involved in vesicle transport between the trans-Golgi network and vacuole that causes abnormal gravitropism in Arabidopsis when mutated [8,10,11,38,39]. SNAREs play an important role in membrane fusion at the vacuole and are involved in the regulation of amyloplast sedimentation in response to gravity and in cell shape development [11,39]. ZIG can form a complex with other types of SNARE proteins, including SYP22/SGR3/VAM3, SYP5, and VAMP727, most likely at the prevacuolar compartment and vacuole [11,[40][41][42].…”

Transcriptome and metabolite analyses provide insights into zigzag-stem formation in tea plants (Camellia sinensis)

“…SNAREs play an important role in membrane fusion at the vacuole and are involved in the regulation of amyloplast sedimentation in response to gravity and in cell shape development [10,47]. ZIG can form a complex with other types of SNARE proteins, including SYP22/SGR3/VAM3, SYP5, and VAMP727, most likely at the prevacuolar compartment and vacuoles [10,[48][49][50].…”