First report on a yellows disease of Allium altyncolicum associated with phytoplasma infection.

Plants of Allium altyncolicum maintained within the Allium collection of the Research Institute of Crop Production Praha-Ruzyne, Section Olomouc (Czech Republic), exhibited symptoms typical of diseases associated with phytoplasmas. Plants showed stunting, yellowing, premature flowering and flower deformities. Anther sterility of flowers of diseased plants was also recorded. Phytoplasma-like structures were detected by transmission electron microscopy in sieve tubes of diseased plants. The use of PCR designed to amplify phytoplasma ribosomal DNA resulted in detection of aster yellows phytoplasma; no phytoplasma was detected in nonsymptomatic plants. On the basis of the RFLP patterns of PCR-amplified ribosomal DNA, the phytoplasma infecting A. altyncolicum was classified as a member of the 16SrI Aster yellows phytoplasma group, subgroup I-B. This is the first report on detection of a phytoplasma disease of A. altyncolicum.