At present, only a single Rhizopus species, R. microsporus, can be found in fresh tempeh produced in Java, Indonesia. The loss of diversity of Rhizopus in tempeh has been associated with the widespread use of commercial tempeh starter in Indonesia since the 2000s. However, the identities of the previous Rhizopus strains associated with tempeh, which have been preserved in a culture collection in Indonesia, have not been verified. The present study aimed to verify the identities of 22 Rhizopus strains isolated from tempeh produced using the traditional tempeh starters from the 1960s to the 2000s. Phylogenetic analysis based on the ITS regions in the rRNA gene sequence data, revealed that the Rhizopus strains belonged to the species R. arrhizus (five strains); R. delemar (14 strains); and R. microsporus (three strains). Verification of the identities of these Rhizopus strains in the present study confirmed the loss of diversity of Rhizopus species in tempeh produced in Indonesia, particularly in Java. Our findings confirmed that the morphological changes in Rhizopus species isolated from tempeh as a result of centuries of domestication.
Tretopileus sphaerophorus, a synnematous hyphomycete with basidiomycetous affinities was newly isolated from the decaying petiole and peduncle of Cocos nucifera collected in Depok, indonesia. The species produced first a bulbil as a propagule on the top of a synnema. After the bulbil had fallen, the synnema proliferated about seven times to produce new bulbils, each time making conspicuous nodes at the upper part. By careful morphological observation, clamp connections were confirmed on the hyphae in the specimens and culture. In culture, each hyphal cell with or without a clamp was found to be dikaryotic by DAPI nuclear staining. Germination of the bulbils occurred first from projecting hyphal tips on their upper surface, which have been treated as germ pores. The inner structure of the bulbils, the hyaline mucus of the bulbils, and conidium-like hyphal fragments were also examined. Phylogenetically, T. sphaerophorus was inferred to be related to the Aphyllophorales based on the nuclear encoded small subunit (18S) rDNA using the homology search system (FASTA) and the neighbour-joining method.
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