Diversity of Endophytic Yeasts from Agricultural Fruits Positive for Phytohormone IAA Production.

This study reports the diversity of cultivable endophytic yeasts from agricultural fruits that respond positively to the plant-promoting property of indole-3-acetic acid (IAA) production. The IAA synthesis by the strains was quantified with an Agilent 1100 series liquid chromatography system. IAA was present in the culture liquid of 72% of all 97 strains examined after three days of cultivation. The most active endophytic yeast strains in this study belonged to the species Aureobasidium pullulans , Candida zeylanoides , Hanseniaspora uvarum , Metschnikowia pulcherrima , Meyerozyma caribbica , Rhodotorula mucilaginosa , and Yarrowia galli . The highest IAA production was observed in the endophytic strain of A. pullulans (9109.19 ± 146.02 μg/g). No significant differences were found between IAA production in strains from agricultural products of different countries. However, the level of IAA production was strictly strain-specific. Our results suggest that the internal tissues of fruits may be a promising source for the isolation of plant-beneficial yeasts that can be used to promote plant growth.