VAPYRIN-like is required for development of the moss .

The () gene in and is required for arbuscular mycorrhizal (AM) symbiosis. The moss has a close homolog (, ), although it does not form AM. Here, we explore the phylogeny of and in land plants, and study the expression and developmental function of in We show that is expressed primarily in the protonema, the early filamentous stage of moss development, and later in rhizoids arising from the leafy gametophores and in adult phyllids. Knockout mutants have specific phenotypes in branching of the protonema and in cell division of the leaves (phyllids) in gametophores. The mutants are responsive to auxin and strigolactone, which are involved in regulation of protonemal branching, indicating that hormonal signaling in the mutants is not affected in hormonal signaling. Taken together, these results suggest that exerts negative regulation of protonemal branching and cell division in phyllids. We discuss and phylogeny and function in land plants in the context of AM symbiosis in angiosperms and development in the moss.