Occurrence of New Pathogenic Species of Streptomyces Causing Common Scab Disease on Potato Tubers in Egypt

Abstract

This study was aimed to identify major species of Streptomyces that are able to cause potato common scab in Egypt. Potato tubers showing typical symptoms of common scab disease were collected from three different regions of Upper Egypt. The causal pathogens were isolated, and morphological, biochemical and pathogenicity tests were conducted in vitro to preliminary identify the isolated Streptomyces isolates. Moreover, the partial 16S rDNA gene sequencing was used to genetically identification of the isolates. Four new pathogenic species that have not previously been reported in Egypt were identified. Four species of Streptomyces rochei, S. rutgersensis, S. lateritius, and S. bottropensis were identified. Isolates S1, S10, S14, S17, S18, S20, and S21 were identified as Streptomyces rochei, isolates S11 was identified as S. rutgersensis, isolates S13 identified as S. lateritius and isolates S15 was identified as S. bottropensis. To the obtained data, this is the first report that S. rochei, S. rutgersensis, S. lateritius, and S. bottropensis cause of potato common scab disease in Egypt. The different of obtained 16S rDNA sequences were deposited at NCBI GenBank with the following accession numbers: (S1) MZ267260, (S10) MZ267264, (S14) MZ267268, (S17) MZ267271, (S18) MZ267272, (S20) MZ267274, (S21) MZ267275, (S11) MZ267265, (S13) MZ267267, and (S15) MZ267269. The four newly identified isolates showed different pathogenicity, morphological and biochemical characteristics.