Research Project
Grant-in-Aid for Scientific Research (C)
The zig-1 mutant of Arabidopsis shows little shoot gravitropism and abnormal stem morphology. Based on the fact that ZIG encodes Qb-SNARE VTI11 involved in trans-Golgi network (TGN)-prevacuolar compartment(PVC)/vacuole vesicle trafficking. I carried out following two projects to study how the vacuole formation and/or function mediated by the TGN-PVC/vacuole vesicular trafficking is involved in higher order physiological functions such as gravitropism and morphogenesis.1.To understand dynamic relationship between amyloplasts that are statoliths for gravity perception and vacuole, we developed an adequate method for the in vivo analysis of their dynamics in the gravity-perceptive cell (endodermis) of the Arabidopsis inflorescence stem. The amyloplasts in the endodermal cells were surrounded almost completely by a thin layer of cytoplasm and the vacuolar membrane and moved around through a complex network of the transvacuolar strands and some dilated areas. Analysis with zig-1 mutant suggested that such dynamic movement of amyloplasts depends on the dynamic feature of vacuolar membrane.2.To elucidate the molecular network of the vesicle transports mediated by VTI11, we have isolated several suppressor mutants of zig-1. One of the suppressor lines, the zig suppressor 1(zip1), strongly and dominantly suppressed the defects of zig-1 both in gravitropism and morphogenesis. The zip1 is a point mutation in the VTI12, a homolog of VTI11. VTI11 and VTI12 exhibit partially overlapped but distinct intracellular localization and have different biological functions in plants. The zip1 mutation gave VTI12 the ability to function as VTI11 by changing both the specificity of SNARE complex formation and its intracellular localization. One amino acid substitution drastically altered VTI12 character to suppress abnormality of higher order physiological function such as gravitropism and morphology.
All 2005 2004 2003 Other
All Journal Article (12 results) Publications (2 results)
Plant Cell 17
Pages: 548-558
Current Biology 15
Pages: 555-560
Current Biology (in press)
Current Opinion in Plant Biology 6/7
Pages: 712-718
Current Opinion in Plant Biology 7/6
Plant Cell 15
Pages: 2885-2889
Proceedings of National Academy of Sciences 100
Pages: 8589-8594
Pages: 2885-2899
PNAS 100
