FIRST REPORT OF A 16SRXI GROUP PHYTOPLASMA 'CANDIDATUS PHYTOPLASMA ORYZAE' ASSOCIATED WITH CYPERUS spp WHITE LEAF DISEASE IN IRAN
M. Salehi, S.A. Esmailzadeh Hosseini
In 2014, Cyperus spp. (Cyperaceae) white leaf (CWL) disease was observed in lime orchards in Minab (Hormozgan province, Iran). Main disease symptoms were whitening of aerial plant parts and stunting. To investigate the phytoplasma presence, total DNAs extracted from five symptomatic and five symptomless Cyperus spp. plants were tested by nested PCR using primers P1/P7 followed by R16F2n/R16R2 (Lee et al., 1998). Amplicons of ca. 1.8 and 1.2 kb, were obtained from samples of symptomatic but not symptomless plants. All amplicons were cloned and sequenced. The obtained 16S rDNA sequences showed 100% identity with each other and a representative of the same sequences deposited in GenBank (accession No. MF136620). BLAST search using the full length 16S rRNA gene sequence revealed that the CWL sequence showed 99% identity with sugarcane white leaf and sugarcane grassy shoot phytoplasmas (AB646271 and KF908792, respectively), representatives of 16SrXI phytoplasma group. Computer-simulated restriction analysis using iPhyClassifier, showed that the RFLP profile of CWL phytoplasma was very similar to the reference pattern of the 16SrXI-B subgroup (X76432). Phylogenetic analysis using Mega software version 7 confirmed that the CWL phytoplasma clustered with16SrXI group phytoplasmas closest to 16SrXI-B subgroup. To our knowledge this is the first report of a 16SrXI group phytoplasma in Iran. Rice and sugarcane plants are two economically important hosts of 16SrXI group-related strains (Arocha and Jones, 2010), thus the CWL-associated phytoplasma could act as a source of inoculum for infecting rice and sugarcane crops in Iran.