The shoot meristem identity gene TFL1 is involved in flower development and trafficking to the protein storage vacuole

Abstract

Plants are unique in their ability to store proteins in specialized protein storage vacuoles (PSVs) within seeds and vegetative tissues. Although plants use PSV proteins during germination, before photosynthesis is fully functional, the roles of PSVs in adult vegetative tissues are not understood. Trafficking pathways to PSVs and lytic vacuoles appear to be distinct. Lytic vacuoles are analogous evolutionarily to yeast and mammalian lysosomes. However, it is unclear whether trafficking to PSVs has any analogy to pathways in yeast or mammals, nor is PSV ultrastructure known in Arabidopsis vegetative tissue. Therefore, alternative approaches are required to identify components of this pathway. Here, we show that an Arabidopsis thaliana mutant that disrupts PSV trafficking identified TERMINAL FLOWER 1 (TFL1), a shoot meristem identity gene. The tfl1-19/mtv5 (for ''modified traffic to the vacuole'') mutant is specifically defective in trafficking of proteins to the PSV. TFL1 localizes to endomembrane compartments and colocalizes with the putative ␦-subunit of the AP-3 adapter complex. Our results suggest a developmental role for the PSV in vegetative tissues.protein trafficking ͉ vegetative tissue ͉ adaptin

Arabidopsis ribosomal proteins control vacuole trafficking and developmental programs through the regulation of lipid metabolism

“…The rpl4d mutant was obtained in our previous screen for vacuole trafficking defects (Fig. 1A) in the vac2 background (6). RPL4 was identified as a general regulator of different vacuolar trafficking pathways (42).…”

“…The NTPP pathway is believed to be common to plants and yeast, and several components of the machinery involved in the sorting of NTPPtype cargoes have been characterized (3,4). The CTPP pathway is believed to be unique to plants, and different genetic approaches have identified components that are specific for that pathway (5,6) The biogenesis of vacuoles and trafficking to this compartment is indispensable for plant viability because plants defective in either pathway result in severe developmental defects or even embryonic lethality (7)(8)(9).…”

Isolation and proteomic analysis of the SYP61 compartment reveal its role in exocytic trafficking in Arabidopsis

“…Immunocytochemistry was carried out in Arabidopsis leaf protoplasts as previously described [68]. Antibodies recognizing CESA1 antibody [55], PEN1 (SYP121), Vamp72 [52] and SNAP33 [69] were diluted 1:1 000 before use.…”

MODIFIED VACUOLE PHENOTYPE1 Is an Arabidopsis Myrosinase-Associated Protein Involved in Endomembrane Protein Trafficking

“…Protein trafficking through the endomembrane system requires specific cargo recognition and delivery mechanisms that are mediated by a series of highly specific targeting signals (Surpin and Raikhel, 2004), whose proper recognition is critical for the function of numerous downstream processes, such as floral development (Sohn et al, 2007), gravitropism (Kato et al, 2002;Surpin et al, 2003;Yano et al, 2003), abiotic stress tolerance (Zhu et al, 2002), autophagy (Surpin et al, 2003;Bassham., 2007), pathogen defense (Robatzek, 2007), and turgor pressure and growth (De, 2000).…”