Surveys reveal the occurrence of phytoplasmas in plants at different geographical locations in Peru

Abstract

Two independent surveys were performed in Peru during February and November 2007 to detect the presence of phytoplasmas within any crops showing symptoms resembling those caused by phytoplasmas. Molecular identifications and characterisations were based on phytoplasma 16S and 23S rRNA genes using nested PCR and terminal restriction fragment length polymorphism (T-RFLP). The surveys indicated that phytoplasmas were present in most of the locations sampled in Peru in both cultivated crops, including carrots, maize, native potatoes, improved potato, tomato, oats, papaya and coconut, and in other plants such as dandelion and the ornamental Madagascar periwinkle (Catharanthus roseus). Phylogenetic analysis of the sequences confirmed that while most of the isolates belong to the 16SrI aster yellows group, which is ubiquitous throughout other parts of South America, one isolate from potato belongs to the 16SrII peanut witches' broom group, and one isolate from tomato and one from dandelion belong to the 16SrIII X-disease group. The use of T-RFLP was validated for the evaluation of phytoplasma-affected field samples and provided no evidence for mixed infection of individual plants with more than one phytoplasma isolate. These data represent the first molecular confirmation of the presence of phytoplasmas in a broad range of crops in Peru.

Maize bushy stunt phytoplasma affects native corn at high elevations in Southeast Mexico

“…Further studies identified the phytoplasma associated with MBS as a 'Candidatus Phytoplasma asteris'-related strain belonging to the 16SrI-B subgroup (Lee et al 1993(Lee et al , 2004. MBS phytoplasma (MBSP) was also detected in Peru (Nault et al 1979;Hodgetts et al 2009), Nicaragua (Hruska et al 1996), Costa Rica , Belize (Henríquez et al 1999), Brazil (Bedendo et al 1997), and Colombia (Alvarez et al 2014). In all countries MBSP was identified as a member of the 16SrI-B subgroup but was never reported as affecting a native variety.…”

Molecular biology and pathogenicity of phytoplasmas

“…Over the last decade, several studies showed that many closely related phytoplasma strains cannot be readily differentiated by analysis of the highly conserved 16S rDNA sequences. Therefore, several less‐conserved genes including rpsV ( rpl22 ), rpsC ( rps3 ), rplP , rpmC , rpsQ , rplN , rplX , rplE , rpsN , rpsH , rplF , rplR , rpsE , rpmD , rplO , tuf , secA , secY , nus , vmp1 , stamp , groEL , rpoB , potC and 23S rRNA genes, and the 16S–23S rRNA spacer region sequences were employed as additional molecular markers for finer differentiation of closely related strains as well as derivative variants for a given strain (Lee et al , , ; Martini et al , ; Hodgetts et al , , ; Cimerman et al , ; Fabre et al , ; Mitrović et al , ; Durante et al , ; Valiunas et al , ; Manimekalai et al , ). These studies revealed that phylogeny based on the mentioned less‐conserved genes was nearly congruent with that inferred by 16S rDNA sequence analysis, indicating similar interrelatedness among phytoplasma taxa.…”

Advances in differentiation and classification of phytoplasmas

“…Over the last decade, several studies showed that many closely related phytoplasma strains cannot be readily differentiated by analysis of the highly conserved 16S rDNA sequences. Therefore, several less‐conserved genes, including rpsV ( rpl22 ), rpsC ( rps3 ), tuf , secA , secY , nus , groEL and 23S rRNA, and the 16S‐23S rRNA spacer region sequences were employed as additional molecular markers for finer differentiation of closely related strains as well as derivative variants for a given strain (Martini et al , ; Hodgetts et al , ; Mitrović et al , ). These studies revealed that phylogeny, based on the mentioned less‐conserved genes, was nearly congruent with that inferred by 16S rDNA sequence analysis, indicating similar interrelatedness among phytoplasma taxa.…”

“…The numerous papers published over the last few years in Annals of Applied Biology , along with those appeared in several other leading international phytopathological and microbiological journals, reflect the tremendous progress made in differentiation and classification, and also in detection and identification of phytoplasmas in both plants and insects. Annals of Applied Biology also published a number of papers on phytoplasma–insect vector relationships, newly reported phytoplasma diseases, aetiological elucidation of decline diseases supposed to be induced by phytoplasmas, colonisation behaviour of phytoplasmas in plants, development of new diagnostic tools and a pathogen eradication method useful to produce healthy plant materials (Granata et al , ; Aldaghi et al , ; Bressan et al , ; Hodgetts et al , ; Wang et al , ; Gitau et al , ; Oropeza et al , ). All these papers can be read in the virtual issue produced by Annals of Applied Biology , which can be viewed at the following site http://www.wiley.com/bw/vi.asp?ref=0003-4746&site=1.…”