Four strains alternating between yeast and filamentous growth morphologies were isolated from
flowers in two regions of Laos. In liquid environment the isolates propagated by budding and
developed irregularly shaped pseudohyphae. On solid media, their yeast cells switched to hyphal
growth which could return to the yeast phase by developing lateral blastoconidia. The sequences
of the D1/D2 domains of the large subunit (LSU) 26S rRNA genes, the internal transcribed
spacer (ITS) regions and the small subunit (SSU) 18S rRNA genes were identical in the four
strains and differed from the corresponding sequences of other yeast species available in
databases by at least 11 % (D1/D2), 13 % (ITS) and 7 % (SSU). In an independent project, two
strains with D1/D2 and ITS sequences very similar to those of the Laotian strains were found in
bark samples collected in Brazil. The six strains also differed from the closest yeast species in
physiological properties, indicating that they represented a hitherto undescribed species.
Phylogenetic analysis of the D1/D2 sequences, and the concatenated sequences of the SSU
rRNA genes, D1/D2 domains of LSU rRNA genes as well as the protein-encoding genes ACT1
and TEF1 placed thestrains close to Hyphopichia. To reflect this position, the novel genus name
Metahyphopichia gen. nov. and the novel species name Metahyphopichia laotica gen. nov., sp.
nov. are proposed for them. The type strain of the type species is 11-1006T
(=CBS 13022T=CCY 092-001-001T=NCAIM Y.02126T) and was isolated in Luang Prabang (Laos).
MycoBank registration numbers are MB 808253 (Metahyphopichia) and MB 808254
(Metahyphopichia laotica).