Characterization of ‘<em>Ca</em>. Phytoplasma asteris’, ‘<em>Ca</em>. Phytoplasma australiense’ and ‘<em>Ca</em>. Phytoplasma mali’ Associated with Russian Olive Witches’-Broom Disease in Iran Using Next-Generation Sequencing

Abstract

Russian olive trees showing witches’-broom disease symptoms in urban green spaces and orchards in northwest Iran were sampled for phytoplasma detection. PCR assays and Sanger sequencing of 16S rRNA gene confirmed that ‘<em>Ca</em>. Phytoplasma asteris’ was associated with Russian olive witches’-broom disease. For genomic characterization of phytoplasma associated with disease, the total DNA of an infected tree was analyzed by Illumina next-generation sequencing (NGS). The NGS analysis generated 46011389 read pairs of raw data with about 6.8 × 10⁹ bp sequences and 31% GC content. Then, MetaPhlAn2 analysis of NGS raw data predicted three phytoplasma species inside the infected Russian olive tree DNA. Finally, the genomes of ‘<em>Ca</em>. Phytoplasma asteris’ with 833199 bp length, ‘<em>Ca</em>. Phytoplasma australiense’ with 762261 bp length and ‘<em>Ca</em>. Phytoplasma mali’ with 518942 bp length were obtained from NGS raw data. This study represents the first report of ‘<em>Ca</em>. Phytoplasma australiense’ and ‘<em>Ca</em>. Phytoplasma mali’ association with Russian olive witches’-broom disease using NGS analyses worldwide.