Identification of Yeasts Isolated from Varieties of Apples and Citrus Using PCR-Fragment Size Polymorphism and Sequencing of ITS1–5.8S-ITS2 region

Abstract

Yeasts play a significant role in the nutrition industry, medicine, and biocontrol of plant pathogens. Certain isolates of yeasts act as antagonist agents in postharvest infections on fruits such as apples and citrus. The main goal of this study was identification of yeasts isolated from different types of Iranian apples and citrus using reliable molecular methods. For preliminary identification of the isolates, each of the internal transcribed spacer 1 (ITS1) and ITS2 regions of ribosomal DNA (rDNA) was amplified separately, and the mixture of both amplicons was electrophoresed on agarose gels. For final discrimination of the selected isolates the entire ITS1-ITS2 was sequenced followed by Blast analysis. The most common identified isolates were species belonged to the following genera: Rhodotorula, Torulaspora, Candida, Pichia, Metschnikowia, and Cryptococcus. Based on our results, PCR-FSP coupled to sequencing had important relevance for phylogenetic analysis to differentiate yeasts. Phylogenetic evaluation of yeasts isolated from fruits based on nucleotide sequences of ITS region of rDNA categorized 18 representative species in 10 distinct lineages. It is concluded that the molecular methods can be very efficient, useful, and precise tools for identification of yeasts.

Keywords:

• yeast
• identification
• apple
• citrus

ACKNOWLEDGMENTS

This work was supported by the Department of Plant Entomology and Plant Protection of Tehran University, Iran.