Plant-pathogenic phytoplasmas were detected by the combined use of fluorescence (DAPI) and electron microscopy (TEM and SEM) in four plant species belonging to the Brassica family, such as cabbage (Brassica oleracea var. capitata) sprouting broccoli (Brassica oleracea var. italica), turnip (Brassica rapa var. rapifera) and kale (Brassica oleracea var. palmifolia) whose samples were collected in several vegetable-growing areas in Latium, Campania, Basilicata and Calabria regions (southern Italy). Their presence in diseased plants was confirmed by PCR-amplification of a phytoplasma 16S rRNA gene fragment. Phytoplasmas were characterized by RFLP analysis of PCR-products using Alu I restriction endonuclease. Diseased plants are characterized by great malformations of floral parts involving virescence and phyllody, and by yellowing, stunting, proliferation of axillary shoots, deformation of the leaves. In most of the fields investigated, the disease incidence ranged from 8 to 15 %, reaching 25 % only in two ones. Results obtained with fluorescence and electron microscope observations are consistent with one another and revealed a great number of phytoplasmas only in mature sieve elements of diseased plants. The RFLP analysis indicates that all phytoplasmas investigated belong to the aster yellows phytoplasma
Detection of phytoplasmas in Brassica spp. in southern Italy and their characterization by RFLP analysis
MARCONE, Carmine;
1995
Abstract
Plant-pathogenic phytoplasmas were detected by the combined use of fluorescence (DAPI) and electron microscopy (TEM and SEM) in four plant species belonging to the Brassica family, such as cabbage (Brassica oleracea var. capitata) sprouting broccoli (Brassica oleracea var. italica), turnip (Brassica rapa var. rapifera) and kale (Brassica oleracea var. palmifolia) whose samples were collected in several vegetable-growing areas in Latium, Campania, Basilicata and Calabria regions (southern Italy). Their presence in diseased plants was confirmed by PCR-amplification of a phytoplasma 16S rRNA gene fragment. Phytoplasmas were characterized by RFLP analysis of PCR-products using Alu I restriction endonuclease. Diseased plants are characterized by great malformations of floral parts involving virescence and phyllody, and by yellowing, stunting, proliferation of axillary shoots, deformation of the leaves. In most of the fields investigated, the disease incidence ranged from 8 to 15 %, reaching 25 % only in two ones. Results obtained with fluorescence and electron microscope observations are consistent with one another and revealed a great number of phytoplasmas only in mature sieve elements of diseased plants. The RFLP analysis indicates that all phytoplasmas investigated belong to the aster yellows phytoplasmaI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
