Inhibitory Effects of Aureobasidium pullulans MHAU2101 Isolated from Domestic Pear Blossom Against Fire Blight

Hyeonseok  Oh1,2   Hyo-Won  Choi1   Yong Hwan  Lee1   Seung Yeup Lee1   Mi-Hyun  Lee1,*   Sang-Keun  Oh2,*   

1Crop Protection Division, National Institute of Agricultural Sciences, Rural Development Administration, Wanju 55365, Korea
2Department of Applied Biology, Chungnam National University, Daejeon 34134, Korea

Abstract

This study was conducted to identify yeast species isolated from domestic pear blossom through gene sequencing and analysis of morphological characteristics, and to confirm specific yeast species inhibitory effects toward fire blight in immature apples, pears, and crab apple blossoms. Yeast morphological characteristics were consistent with the known characteristics of Aureobasidium pullulans. Nucleotide sequencing of the D1/D2 region of large-subunit (LSU) 26S ribosomal DNA and the internal transcribed spacer (ITS) region confirmed its identity as A. pullulans (MHAU2101). Inoculation of immature fruits with A. pullulans MHAU2101 before exposure to Erwinia amylovora prevented fire blight symptoms in apples and pears. A. pullulans MHAU2101 treated crab apple blossoms had a significantly lower flower infection rate than untreated blossoms, revealing 64% of the potency of streptomycin. The A. pullulans MHAU2101 treated group also displayed lower E. amylovora density in both pistil and hypanthium compared to the untreated group, especially in the hypanthium. This study confirms that A. pullulans MHAU2101 isolated from domestic pear blossom can effectively suppress the onset of fire blight.

Figures & Tables

Fig. 1. Morphological characteristics of MHAU2101. Colony of the yeast isolate grown for 14 days on potato dextrose agar medium (A), melanised hyphae and conidia, scale bar=50 μm (B), production of blastospores from the swollen cell, scale bar=10 μm (C).