021 Strawberry Fruit Phyllody Caused by Phytoplasmas

Strawberry fruit phyllody, production of leaves and other vegetative organs from fruit tissue around achenes, has been ascribed to physiological causes due to temperature conditions during transplant cold storage, plant response to changing seasonal conditions at flower initiation time, and to phytoplasma infection. In examination of phylloid fruits from different strawberry clones and from different locations and sources, we found four distinct phytoplasmas associated with phyllody of strawberry fruit: strawberry multicipita (SM) phytoplasma (16S rRNA group VI, subgroup B), STRAWB2 phytoplasma (16S rRNA group I, subgroup K), clover yellow edge phytoplasma (16S rRNA group III, subgroup A), and a new group III phytoplasma. The SM and STRAWB2 phytoplasmas were detected in plants with phylloid fruit that also exhibited stunting and crown proliferation (SM phytoplasma) or stunting and leaf chlorosis (STRAWB2 phytoplasma). In no instances did we fail to detect phytoplasmas in phylloid fruit. To our knowledge, this is the first report to associate strawberry fruit phyllody with the presence of these phytoplasmas and to report that phytoplasmas other than those belonging to 16S rRNA group I (aster yellows group) can also be associated with strawberry fruit phyllody.