Genetic Analysis of Phytophthora nicotianae Populations from Different Hosts Using Microsatellite Markers.
In all, 231 isolates of Phytophthora nicotianae representing 14 populations from different host genera, including agricultural crops (Citrus, Nicotiana, and Lycopersicon), potted ornamental species in nurseries (Lavandula, Convolvulus, Myrtus, Correa, and Ruta), and other plant genera were characterized using simple-sequence repeat markers. In total, 99 multilocus genotypes (MLG) were identified, revealing a strong association between genetic grouping and host of recovery, with most MLG being associated with a single host genus. Significant differences in the structure of populations were revealed but clonality prevailed in all populations. Isolates from Citrus were found to be genetically related regardless of their geographic origin and were characterized by high genetic uniformity and high inbreeding coefficients. Higher variability was observed for other populations and a significant geographical structuring was determined for isolates from Nicotiana. Detected differences were related to the propagation and cultivation systems of different crops. Isolates obtained from Citrus spp. are more likely to be distributed worldwide with infected plant material whereas Nicotiana and Lycopersicon spp. are propagated by seed, which would not contribute to the spread of the pathogen and result in a greater chance for geographic isolation of lineages. With regard to ornamental species in nurseries, the high genetic variation is likely the result of the admixture of diverse pathogen genotypes through the trade of infected plant material from various geographic origins, the presence of several hosts in the same nursery, and genetic recombination through sexual reproduction of this heterothallic species.
First, fourth, and sixth authors: Dipartimento di Agraria, Università Mediterranea di Reggio Calabria, Località Feo di Vito, 89122 Reggio Calabria, Italy; second author: United States Department of Agriculture-Agricultural Research Service (USDA-ARS), 1636 East Alisal Street, Salinas, CA 93905; third author: Dipartimento di Agricoltura, Alimentazione e Ambiente, Università degli Studi, Via S. Sofia 100, 95123 Catania, Italy; and fifth author: Horticultural Crops Research Laboratory, USDA-ARS, Corvallis, OR.
Antonio
A
Biasi
First, fourth, and sixth authors: Dipartimento di Agraria, Università Mediterranea di Reggio Calabria, Località Feo di Vito, 89122 Reggio Calabria, Italy; second author: United States Department of Agriculture-Agricultural Research Service (USDA-ARS), 1636 East Alisal Street, Salinas, CA 93905; third author: Dipartimento di Agricoltura, Alimentazione e Ambiente, Università degli Studi, Via S. Sofia 100, 95123 Catania, Italy; and fifth author: Horticultural Crops Research Laboratory, USDA-ARS, Corvallis, OR.
Frank N
FN
Martin
First, fourth, and sixth authors: Dipartimento di Agraria, Università Mediterranea di Reggio Calabria, Località Feo di Vito, 89122 Reggio Calabria, Italy; second author: United States Department of Agriculture-Agricultural Research Service (USDA-ARS), 1636 East Alisal Street, Salinas, CA 93905; third author: Dipartimento di Agricoltura, Alimentazione e Ambiente, Università degli Studi, Via S. Sofia 100, 95123 Catania, Italy; and fifth author: Horticultural Crops Research Laboratory, USDA-ARS, Corvallis, OR.
Santa O
SO
Cacciola
First, fourth, and sixth authors: Dipartimento di Agraria, Università Mediterranea di Reggio Calabria, Località Feo di Vito, 89122 Reggio Calabria, Italy; second author: United States Department of Agriculture-Agricultural Research Service (USDA-ARS), 1636 East Alisal Street, Salinas, CA 93905; third author: Dipartimento di Agricoltura, Alimentazione e Ambiente, Università degli Studi, Via S. Sofia 100, 95123 Catania, Italy; and fifth author: Horticultural Crops Research Laboratory, USDA-ARS, Corvallis, OR.
Gaetano Magnano
GM
di San Lio
First, fourth, and sixth authors: Dipartimento di Agraria, Università Mediterranea di Reggio Calabria, Località Feo di Vito, 89122 Reggio Calabria, Italy; second author: United States Department of Agriculture-Agricultural Research Service (USDA-ARS), 1636 East Alisal Street, Salinas, CA 93905; third author: Dipartimento di Agricoltura, Alimentazione e Ambiente, Università degli Studi, Via S. Sofia 100, 95123 Catania, Italy; and fifth author: Horticultural Crops Research Laboratory, USDA-ARS, Corvallis, OR.
Niklaus J
NJ
Grünwald
First, fourth, and sixth authors: Dipartimento di Agraria, Università Mediterranea di Reggio Calabria, Località Feo di Vito, 89122 Reggio Calabria, Italy; second author: United States Department of Agriculture-Agricultural Research Service (USDA-ARS), 1636 East Alisal Street, Salinas, CA 93905; third author: Dipartimento di Agricoltura, Alimentazione e Ambiente, Università degli Studi, Via S. Sofia 100, 95123 Catania, Italy; and fifth author: Horticultural Crops Research Laboratory, USDA-ARS, Corvallis, OR.
Leonardo
L
Schena
D018556:Crops, Agricultural; D014644:Genetic Variation; D005828:Genetics, Population; D005838:Genotype; D005843:Geography; D019684:Magnoliopsida / Q000469:parasitology*; D018895:Microsatellite Repeats / Q000235:genetics*; D010838:Phytophthora / Q000235:genetics* / Q000302:isolation & purification; D010935:Plant Diseases / Q000469:parasitology*