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In two of Iran's central provinces, several herbaceous plants showing phytoplasma disease symptoms were collected to detect 'Canididatus Phytoplasma asteris'-related phytoplasmas. Confirmation of an association of phytoplasmas with diseased plants was done using polymerase chain reaction (PCR) assays having the phytoplasma universal primer pairs P1/P7 followed by R16F2n/ R16R2 in nested PCR. Then, for detection of 'Ca. P. asteris', DNA samples were subjected to amplification of rp and tuf genes using specific primer pairs rp(I)F1A/rp(I)R1A and fTufAy/rTufAy, respectively. Restriction fragment length polymorphism or RFLP analyses of rp gene fragments using Tsp509I restriction enzyme as well as sequence analyses indicated that 'Ca. P. asteris'-related phytoplasmas associated with carrot, niger seed and scallion plants in these regions, belong to the rpI-L subgroup. This research is the first report of carrot, niger seed, and scallion infection with phytoplasmas belonging to the rpI-L subgroup.

Abstract: During field surveys in 2015, a phytoplasma‐associated disease was identified in Narcissus tazetta plants in Behbahan, Iran. The characteristic symptoms were phyllody and virescence. The presence of phytoplasma in symptomatic plants was confirmed using PCR amplification and sequencing of 16S rRNA, tuf, secY and vmp1 genes. Based on the blastn results, the sequences of 16S rRNA, tuf, secY and vmp1 genes shared, respectively, 99%, 100%, 99% and 99% sequence identity with phytoplasma strains in 16SrXII‐A subgroup. RFLP and phylogenetic analyses using the sequences of 16S rRNA, tuf and secY genes confirmed the assortment of studied strains to 16SrXII‐A phytoplasma subgroup. Sequence comparison of these four genes revealed that all the sequences of 28 strains studied were identical. To the best of our knowledge, the association of “Candidatus Phytoplasma solani” with N. tazetta was demonstrated for the first time in the world. [ABSTRACT FROM AUTHOR]

During several surveys in extensive areas in central Iran, apple trees showing phytoplasma diseases symptoms were observed. PCR tests using phytoplasma universal primer pairs P1A/P7A followed by R16F2n/R16R2 confirmed the association of phytoplasmas with symptomatic apple trees. Nested PCR using 16SrX group-specific primer pair R16(X)F1/R1 and aster yellows group-specific primer pairs rp(I)F1A/rp(I)R1A and fTufAy/ rTufAy indicated that apple phytoplasmas in these regions did not belong to the apple proliferation group, whereas aster yellows group-related phytoplasmas caused disease on some trees. Restriction fragment length polymorphism ( RFLP) analyses using four restriction enzymes ( HhaI, HpaII, HaeIII and RsaI) and sequence analyses of partial 16S rRNA and rp genes demonstrated that apple phytoplasma isolates in the centre of Iran are related to ' Ca. Phytoplasma asteris' and ' Ca. Phytoplasma aurantifolia'. This is the first report of apples infected with ' Ca. Phytoplasma asteris' in Iran and the first record from association of ' Ca. Phytoplasma aurantifolia' with apples worldwide. [ABSTRACT FROM AUTHOR]

Potato plants with symptoms suggestive of potato purple top disease (PPTD) occurred in the central, western and north-western regions of Iran. Polymerase chain reaction (PCR) and nested PCR assays were performed using phytoplasma universal primer pair P1/P7 followed by primer pairs R16F2n/R16R2 and fU5/rU3 for phytoplasma detection. Using primer pairs R16F2n/R16R2 and fU5/rU3 in nested PCR, the expected fragments were amplified from 53% of symptomatic potatoes. Restriction fragment length polymorphism (RFLP) analysis using AluI, CfoI, EcoRI, KpnI, HindIII, MseI, RsaI and TaqI restriction enzymes confirmed that different phytoplasma isolates caused PPTD in several Iranian potato-growing areas. Sequences analysis of partial 16S rRNA gene amplified by nested PCR indicated that ' Candidatus Phytoplasma solani', ' Ca. Phytoplasma astris' and ' Ca. Phytoplasma trifolii' are prevalent in potato plants showing PPTD symptoms in the production areas of central, western and north-western regions of Iran, although ' Ca. Phytoplasma solani' is more prevalent than other phytoplasmas. This is the first report of phytoplasmas related to ' Ca. Phytoplasma astris', ' Ca. Phytoplasma solani' and ' Ca. Phytoplasma trifolii' causing PPTD in Iran. [ABSTRACT FROM AUTHOR]

Alfalfa is believed to have originated in north-western Iran and has a long history of coexistence with its bacterial symbiont Sinorhizobium in soils of Iran. However, little is known about the diversity of Sinorhizobium strains nodulating Iranian alfalfa genotypes. In this study, Sinorhizobium populations were sampled from eight different Iranian sites using three cultivars of Medicago sativa as trap host plants. A total of 982 rhizobial strains were isolated and species were identified showing a large prevalence of Sinorhizobium meliloti over Sinorhizobium medicae. Analysis of salt tolerance demonstrated a great phenotypic diversity. The genetic diversity of the Sinorhizobium isolates was analysed using BOX-PCR and enterobacterial repetitive intergenic consensus (ERIC)-PCR. Patterns of BOX-PCR fingerprinting were statistically analysed with AMOVA to evaluate the role of plant variety and site of origin in the genetic variance observed. Results indicated that most of the total molecular variance was attributable to divergence among strains isolated from different sites and cultivars (intrapopulation, strain-by-strain variance). Moreover, the analysis showed the presence of two geographic populations (west and north-west), indicating that the effect of the site of origin could be more relevant in shaping population genetic diversity than the effect of cultivar or individual plant. [ABSTRACT FROM AUTHOR]

White clover plants showing little leaf and leaf reddening symptoms were observed in Isfahan Province in central Iran. Restriction fragment length polymorphism analyses of nested PCR-amplified fragments from Iranian clover little leaf phytoplasma isolates and representative phytoplasmas from other phytoplasma groups using Alu I, Cfo I, Kpn I and Rsa I restriction enzymes indicated that the clover phytoplasma isolates are related to the peanut WB group. Sequence analyses of partial 16 S r RNA fragments showed that Iranian clover little leaf phytoplasma has 99% similarity with soybean witches'-broom phytoplasma, a member of the peanut WB (16 Sr II) phytoplasma group. This is the first report of clover infection with a phytoplasma related to the 16 Sr II group. [ABSTRACT FROM AUTHOR]

Shrubs of niger seed with phyllody and internode elongation symptoms suggestive of phytoplasma infections occurred in the central regions of Iran. Phytoplasma was detected by polymerase chain reaction (PCR) and nested PCR amplifications using phytoplasma universal primer pairs P1/P7 and R16F2n/R16R2. Using aster yellows group-specific primer pair rp(I)F1A/rp(I)R1A, a fragment of 1212 bp of the rp genes was amplified from DNA samples of infected plants. Random fragment length polymorphism (RFLP) analyses of R16F2n/R16R2-amplified products using the CfoI restriction enzyme confirmed that Iranian niger seed phyllody phytoplasma is associated with aster yellows group phytoplasmas. Sequence analyses of the partial rp genes fragment indicated that the Iranian niger seed phyllody phytoplasma, which was collected from central regions of Iran, is related to ' Candidatus Phytoplasma asteris'. This is the first report of a phytoplasma infecting the niger seed plant. [ABSTRACT FROM AUTHOR]

Symptoms suggestive of phytoplasma diseases were observed in infected sweet cherry trees growing in the central regions of Iran. Phytoplasmas were detected in symptomatic trees by the nested polymerase chain reaction (nested PCR) using phytoplasma universal primer pairs (P1/Tint, PA2F/R, R16F2/R2 and NPA2F/R). Restriction fragment length polymorphism analyses of 485 bp DNA fragments amplified in nested PCR revealed that different phytoplamas were associated with infected trees. Sequence analyses of phytoplasma 16S rRNA gene and 16S-23S intergenic spacer region indicated that the phytoplasmas related to ‘ Ca. Phytoplasma asteris ’ and peanut WB group infect sweet cherry trees in these regions. This is the first report of the presence of phytoplasmas related to ‘ Ca. Phytoplasma asteris’ and peanut WB group in sweet cherry trees. [ABSTRACT FROM AUTHOR]