Arabidopsis AtBECLIN 1/AtAtg6/AtVps30 is essential for pollen germination and plant development

Pollen germination on the surface of compatible stigmatic tissues is an essential step for plant fertilization. Here we report that the Arabidopsis mutant bcll is male sterile as a result of the failure of pollen germination. We show that the bcll mutant allele cannot be transmitted by male gametophytes and no homozygous bcll mutants were obtained. Analysis of pollen developmental stages indicates that the bcll mutation affects pollen germination but not pollen maturation. Molecular analysis demonstrates that the failure of pollen germination was caused by the disruption of AtBECLIN 1. AtBECLIN 1 is expressed predominantly in mature pollen and encodes a protein with significant homology to Beclin 1/Atg6Vps30 required for the processes of autophagy and vacuolar protein sorting (VPS) in yeast. We also show that AtBECLIN 1 is required for normal plant development, and that genes related to autophagy, VPS and the glycosylphosphatidylinositol anchor system, were affected by the deficiency of AtBECLIN 1.