An Arabidopsis homolog of yeast ATG6/VPS30 is essential for pollen germination

Plant Physiol. 2007 Mar;143(3):1132-9. doi: 10.1104/pp.106.093864. Epub 2007 Jan 26.

Abstract

Yeast (Saccharomyces cerevisiae) Atg6/Vps30 is required for autophagy and the sorting of vacuolar hydrolases, such as carboxypeptidase Y. In higher eukaryotes, however, roles for ATG6/VPS30 homologs in vesicle sorting have remained obscure. Here, we show that AtATG6, an Arabidopsis (Arabidopsis thaliana) homolog of yeast ATG6/VPS30, restored both autophagy and vacuolar sorting of carboxypeptidase Y in a yeast atg6/vps30 mutant. In Arabidopsis cells, green fluorescent protein-AtAtg6 protein localized to punctate structures and colocalized with AtAtg8, a marker protein of the preautophagosomal structure. Disruption of AtATG6 by T-DNA insertion resulted in male sterility that was confirmed by reciprocal crossing experiments. Microscopic analyses of AtATG6 heterozygous plants (AtATG6/atatg6) crossed with the quartet mutant revealed that AtATG6-deficient pollen developed normally, but did not germinate. Because other atatg mutants are fertile, AtAtg6 likely mediates pollen germination in a manner independent of autophagy. We propose that Arabidopsis Atg6/Vps30 functions not only in autophagy, but also plays a pivotal role in pollen germination.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Vesicular Transport / analysis
  • Adaptor Proteins, Vesicular Transport / genetics
  • Adaptor Proteins, Vesicular Transport / physiology*
  • Arabidopsis / growth & development*
  • Arabidopsis / metabolism
  • Arabidopsis / ultrastructure
  • Arabidopsis Proteins / analysis
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / physiology*
  • Autophagy
  • Beclin-1
  • Germination
  • Green Fluorescent Proteins / analysis
  • Molecular Sequence Data
  • Mutation
  • Pollen / growth & development
  • Pollen / metabolism
  • Pollen / ultrastructure
  • Protein Transport
  • Recombinant Fusion Proteins / analysis
  • Saccharomyces cerevisiae / genetics
  • Vacuoles / metabolism

Substances

  • Adaptor Proteins, Vesicular Transport
  • Arabidopsis Proteins
  • Beclin-1
  • Recombinant Fusion Proteins
  • beclin 1 protein, Arabidopsis
  • Green Fluorescent Proteins

Associated data

  • GENBANK/AY039613
  • GENBANK/BT024554