Phytoplasma infection may affect morphology, regeneration and pyrethrin content in pyrethrum shoot culture

The aim of the work was to infect pyrethrum (Tanacetum cinerariifolium (Trevir.) Schultz-Bip.), an important secondary metabolite pyrethrin producing plant, with MA phytoplasma (16S rRNA group III, subgroup B) to initiate tissue culture of phytoplasma-infected plants, and to examine possible effects of infection on pyrethrin content, morphology, and regenerative capacity in shoot culture.Phytoplasma transmission was achieved by using an insect vector (Euscelidius variegatus) making pyrethrum as a new host for phytoplasma. The infection significantly changed the morphology and regenerative capacity of shoots and roots. The infected shoots and roots were shorter and thinner and an increase in proliferation of both was observed. Phytoplasma infection significantly decreased pyrethrin content in shoots, as measured by HPLC.The possibility of long-term maintenance of phytoplasma was also studied. The presence of phytoplasma in shoots was confirmed periodically over 4 years by PCR assay. Possible physiological reasons for a balanced phytoplasma–host system are discussed.