Molecular characterization of effector protein SAP54 in Bellis virescence phytoplasma (16SrIII-J)

Abstract

Phytoplasmas are wall-less bacteria with a parasitic lifestyle responsible for numerous plant diseases worldwide. Since the introduction of next generation sequencing technologies, genome wide studies of these pathogens are flourishing and a handful of phytoplasma genomes are available in public databases. In South America, phytoplasmas from the 16SrIII group (X-disease) are the most widely distributed, but only one draft genome from a 16SrIII-J phytoplasma-infected periwinkle plant has been generated (phytoplasma Vc33). Here, in grafting experiments, we characterized the phenotypic signatures of an Argentinian daisy-derived isolate of a 16SrIII-J phytoplasma (Bellis virescence phytoplasma) infecting periwinkle. Moreover, we applied a pipeline for genome-wide annotation of the Vc33 genome and identified the effector protein SAP54. We then employed the obtained data to amplify, clone, sequence and characterize a SAP54 orthologue protein from the Bellis virescence phytoplasma. Structural analyses suggest that the identified SAP54 effector is highly conserved. The results gathered here could provide the basis for reverse genetics experiments using 16SrIII-J SAP54 proteins to assess their eventual role in pathogenesis.