Artemisia vulgaris, a new host of 16SrV‐C phytoplasma related strains infecting black alder in Poland

Abstract

AbstractYellowing of leaf tissue and strongly deformed shoots were observed in common mugwort (Artemisia vulgaris L.) growing in a nature reserve in Southern Poland. Similar foliage chlorosis together with abnormal shoot proliferation was noticed on alder tree (Alnus glutinosa Gaertn.) growing next to the common mugwort. DNA specific fragments coding 16S rRNA and ribosomal proteins (rp) were amplified from mugwort and alder samples using direct and nested PCR (Polymerase Chain Reaction) assays. Phylogenetic relationships inferred from 16S and rps3 genes indicated that strains infecting mugwort and alder were most closely related to phytoplasmas of subgroups 16SrV‐C and 16SrV‐D. Based on the restriction fragment length polymorphism (RFLP) analysis of the 16S rDNA, the investigated phytoplasma strains were classified to subgroup 16SrV‐C. Two sequence variants of the rps3 gene which differed by a single nucleotide were detected in all analysed samples by pairwise analysis of the aligned reads. Taking into account that this single‐nucleotide polymorphism (SNP) occurs among 16SrV‐C and 16SrV‐D related phytoplasmas and that the phytoplasmas have a single copy of rp operon, we concluded that each plant species was infected by two distinct, closely related phytoplasma strains. To the best of our knowledge, this is the first report of group 16SrV‐C related phytoplasmas infecting common mugwort worldwide, adding a new host species that is possibly linked to the spread of the alder pathogen in Eastern Europe. Although alder yellows phytoplasma has been frequently found in Europe, this is the first detection of phytoplasmas associated with alder in Poland.