Surpin Marci 2885-99 Carter David Saito Cheiko Bandyopadhyay Anindita Kovaleva Valentina Tasaka Masao The VTI family of SNARE proteins is necessary for plant viability and mediates different protein transport pathways. Raikhel Natasha 12 The Arabidopsis genome contains a family of v-SNAREs: VTI11, VTI12, and VTI13. Only VTI11 and VTI12 are expressed at appreciable levels. Although these two proteins are 60% identical, they complement different transport pathways when expressed in the yeast vti1 mutant. VTI11 was identified recently as the mutated gene in the shoot gravitropic mutant zig. Here, we show that the vti11 zig mutant has defects in vascular patterning and auxin transport. An Arabidopsis T-DNA insertion mutant, vti12, had a normal phenotype under nutrient-rich growth conditions. However, under nutrient-poor conditions, vti12 showed an accelerated senescence phenotype, suggesting that VTI12 may play a role in the plant autophagy pathway. VTI11 and VTI12 also were able to substitute for each other in their respective SNARE complexes, and a double-mutant cross between zig and vti12 was embryo lethal. These results suggest that some VTI1 protein was necessary for plant viability and that the two proteins were partially functionally redundant. Morita Miyo T 2003 Dec 15 Murphy Angus Zheng Haiyan Blakeslee Joshua J 14615598 Surpin Marci et al. 2003 Dec. Plant Cell 15(12):2885-99. Avila Emily