First record of a Candidatus phytoplasma associated with little leaf disease of Portulaca grandiflora

Abstract

This paper reports Portulaca grandiflora as a new host of a Candidatus phytoplasma and demonstrates its association with the little leaf disease on P. grandiflora. Plants exhibited typical visual symptoms of a phytoplasma, with reduced leaf size. Pleomorphic bodies, observed by transmission electron microscopy, were restricted to the phloem of symptomatic tissue. However, no bacteria, fungi or viruses were observed under transmission electron microscopy. Products of the expected size were amplified by PCR using nested, phytoplasma-specific primer pairs. In addition, plants temporarily showed amelioration of phytoplasma symptoms following treatment with the antibiotic tetracycline.