Molecular markers to evaluate genetic diversity among Venturia inaequalis isolates obtained from apple plantations in Isparta Province

Authors: SUAT KAYMAK, NUH BOYRAZ, JON DANIELS

Abstract: Turkey, the third leading apple producer in world, produces approximately 2.6 million tons of apples per year. Venturia inaequalis, the causal agent of apple scab, is a major fungal disease among apples varieties. This study was conducted in accordance with the plant protection method for isolates collected from the apple production areas in Isparta Province. The purpose of this study was to determine genetic differences among V. inequalis isolates causing apple scab, and to discriminate the effects of varieties and geographical origins on genetic diversity. For this purpose, a total of 83 samples from the leaves and fruits of infected plants were collected to obtain isolates from apple scab. Of these, 67 isolates were obtained by isolating single conidia. Genetic differences and the relationship of the isolates were evaluated using random amplified polymorphic DNA (RAPD), intersimple sequence repeat (ISSR), simple sequence repeat (SSR), and sequence-related amplified polymorphism (SRAP) markers. The marker techniques SRAP and ISSR were used for the first time in this study to determine the genotype of the isolates of V. inaequalis. There was no relationship between apple varieties and geographic isolation or source of cultivar patterns. Variance analysis and molecular data of clustering from the isolates at district level revealed highly genetic similarity among populations. Additionally, SSR and SRAP markers were found to be more informative and consistent than other marker techniques. This study was the first report on population genetics of V. inaequalis identified with molecular markers in Turkey.

Keywords: Apple, genetic diversity, ISSR, RAPD, SRAP, SSR, Venturia inaequalis

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