Association of a phytoplasma from ribosomal subgroup 16SrXII‐A with walnut witches’‐broom in Iran

Walnut trees displaying symptoms similar to those caused by phytoplasmas, including foliar chlorosis, yellowing and shortening of internodes, were found in a fruit orchard the north Fars province, Iran 2020 (Fig. 1). Samples collected analysed PCR detect identify possible phytoplasma(s) associated with diseased plants. Four four asymptomatic walnut sampled for presence phytoplasma. Total DNA was extracted from 0.1 g midribs using CTAB method. Nested performed universal phytoplasma primers P1/P7 (Deng & Hiruki, 1991) first round, R16F2n/R16R2 (Smart et al., 1996) second. products expected size, c. 1.2 kb, obtained all plants but not symptomless ones. The nucleotide sequence determined directly submitted GenBank (Accession No. MZ005313). A BLAST search showed that witches’-broom had highest identity (99.9%) Iranian alfalfa (KT763373), member ribosomal subgroup 16SrXII-A (‘Candidatus Phytoplasma solani’). Virtual RFLP patterns iPhyclassifier (https://plantpathology.ba.ars.usda.gov/cgibin/resource/iphyclassifier.cgi) supported analysis results. reported Iowa, USA group 16SrIII (‘Ca. P. pruni’) (Yun Harrington 2011). In Iran, 16SrXII has been alfalfa, almond, aubergine, grapevine, peach, plum tomato (Siampour 2019). It also identified Cannabis sativa (Sichani 2011) Salix babylonica (Zamharir Taheri, 2017). orchards are adjacent stone vineyards, so it is likely this transferred such crops trees. Since large areas grown may be serious threat cultivation. To best our knowledge, report association related globally. authors would like thank Dr. Sadegh Sadeghi Mr. Mohsen Amiri great help field.