Yeasts associated with mines on tree leaves in the urban areas / Levaduras asociadas a minas en hojas de árboles en zonas urbanas

ABSTRACT

Mines on tree leaves and undamaged leaves were studied to investigate yeast complexes in urban areas (Aesculus hippocastanum, miner — Cameraria ohridella; Betula verrucosa, miner — Caloptilia betulicola; Populus nigra, miner — Lithocolletis populifoliella; Quercus robur, miner — Tischeria companella; Salix caprea, miner — Trachys minuta; Syringa vulgaris, miner — Caloptilia syringella; Tilia cordata, miner — Phyllonorycter issikii; Ulmus laevis, miner — Carpatolechia fugitivella). The abundance and taxonomic structure of yeasts were studied using a surface plating method on solid media (GPY agar). Identification of yeast species was based on the ITS rDNA nucleotide sequence. The average abundance of yeasts during the first stages of mine formation in the internal tissues of leaves was 103 cfu/g. After 23–25 days, during the last stage of larval metamorphosis before mine destruction, the abundance of yeasts in the mines increased by two orders of magnitude to 105 cfu/g. No significant differences were observed in the abundance of yeasts in mines formed by different insects on different trees. A total of twelve yeast species were observed. The fast-growing ascomycetous yeasts Hanseniaspora uvarum and H. occidentalis dominated the mines. On undamaged leaves, the basidiomycetous yeasts Papiliotrema flavescens and Rhodotorula mucilaginosa, typical in the phyllosphere, dominated. The opportunistic yeast Candida parapsilosis was detected in the yeast complexes of all mines examined and was not found on the surface of leaves. Comparison of the relative abundance of yeast species between the studied mines and undamaged leaves using principal component analysis showed that all studied yeast communities in the mines were significantly different from the epiphytic yeast complexes of the undamaged leaves. Thus, miners in urban environments provoke the formation of short-lived endophytic yeast complexes with high abundance of Hanseniaspora. For leaf miners, the yeasts serve primarily as a food source for insect larvae rich in vitamins and amino acids. The adult leaf miners, in turn, contribute to the reproduction of the yeasts and create favorable conditions for their development.(AU)