Ochroconis Species Isolated from Limestone Areas as the Origin of Indoor Ochroconis.

The molecular, morphological, and physiological features of 42 strains of Ochroconis collected from many limestone areas were studied. Ochroconis strains are often found in limestone areas, although they have rarely been found in other wild areas, e. g. forests. Moreover, many strains from these areas grew on alkaline media (pH 9.7) and media with soap. They were phylogenetically more variable than Ochroconis strains previously found indoors or at city parks. Thus, the Ochroconis strains are thought to have adapted to the alkaline soil, specifically found in limestones. It is assumed that some strains of Ochroconis originally grew in the limestones and immigrated into park soils with the fine dust of cement and into indoor environments. More species of Ochroconis, with the ability to use surfactants as nutrients, are distributed in limestone areas than indoors or in city parks. Moreover, these fungi were found randomly in the phylogenetic trees of Ochroconis. Although only O. humicola was often found indoors and used surfactants, this fungus was newly found in the limestone areas of Okinawa Prefecture. Ochroconis humicola originally grew outdoors and seems to have immigrated to and propagated indoors. Thus, this species may have originated from the subtropical limestone areas.