Required for anther development and early tapetal function during microspore maturation (PubMed:18397379, PubMed:21957980). Regulates callose dissolution required for microspores release from the tetrads (PubMed:18397379). Inflorescences-specific (PubMed:18397379). Accumulates in anthers, especially in tapetum and meiocytes/microsporocytes and microspores during anther development (PubMed:17666023, PubMed:18397379). During anther development, first confined to meiocytes, tapetal and middle layer cells. At the microspore stage, mainly expressed in the tapetum and microspores. Later observed in developing pollen grains. Male-sterile mutant, defective in tapetal development, characterized by irregular and excessive division, redundant cells and leading to dysfunction of the tapetum (PubMed:18397379, PubMed:21957980). Impaired callose dissolution resulting in altered microspores release from the tetrads and no pollen production (PubMed:18397379). Extended C-terminus.