• The Plant Pathology Journal
• /
• 제21권2호
• /
• pp.106-110
• /
• 2005

Sclerotinia sclerotiorum attacks most of the vegetable crops in the Jordan valley. Twenty-five samples/isolates were obtained in a complete coverage of that region. They were characterized for their mycelium incompatibility, and specific gene amplified using the primer SSREV/SSFWD. All isolates gave similar single band around 278 bp. Thirteen isolates were completely incompatible with the other 12 ones. The latter ones fell into four subgroups of mycelium incompatibility. RAPD analysis using three primers (OPA-2, OPA-10, and OPA-18) clustered the 25 isolates into subgroups in agreement with their morphological separation, indicating close correlation between amplified gene(s) and the gene(s) of incompatibility. All highly virulent isolates were among the group of 13, indicating a well established genomic type pathogen in this region.

• The Plant Pathology Journal
• /
• 제27권2호
• /
• pp.116-119
• /
• 2011

Pyrenophora graminea, the causal agent of leaf stripe disease, is an economically important pathogen of barley found worldwide. Forty-four isolates of diverse geographical origin within Syria were grouped into vegetative compatibility groups (VCGs) by demonstrating heterokaryosis by complementation tests using nitrate nonutilizing (nit) mutants. All isolates were grouped into three VCGs-1-A, 1-B and 1-C. No self-incompatibility was observed in any of the isolates tested. VCG 1-A was the most common group within growing regions in Syria and proved to be the most virulent of the VCGs identified. These data indicate that the level of virulence in P. graminea is related to VCG.

• The Plant Pathology Journal
• /
• 제19권6호
• /
• pp.269-273
• /
• 2003

A total of 57 isolates of Colletotrichum gloeosporioides were recovered from diseased tissues of Hall's crab apple (Malus haliana), 3 cultivars of edible apple (M. pumila var. dulcissima), red pepper (Capsicum annum), and grapevine (Vitis vinifera) fruits. All isolates showed strong virulence on their own host plants. Isolates from edible apple exhibited high level of cultivar specificity in pathogenicity tests. Ten isolates from apple cultivar 'Fuji' were virulent on 'Jonathan' and 'Rall's Genet'. However, 12 isolates from 'Jonathan' and 'Rall's Genet' were not virulent on 'Fuji'. Among the 24 isolates from red pepper, only seven and two isolates were infective on edible apple and grapevine fruits, respectively. All six isolates from grapevine were only virulent on their own host. These isolates were grouped into five vegetative compatibility groups (VCGs), A, B, C, D, and E, by demonstrating heterokaryosis through complementation using nitrate-nonutilizing (nit) mutants. Among them, isolates belong to VCG-A and VCG-D accounted for 24 and 17 isolates； those in VCG-A exhibited wide host range involving Hall's crab apple, all three edible apple cultivars, and red pepper. On the other hand, isolates of VCG-D and VCG-E showed limited host range specific to red pepper and grapevine, respectively. Taken together, the data suggest that among C. gloeosporioides isolates, the concepts of pathotype and/or forma specialis may exist, and that three is a relationship between host specificity and VCG grouping among C. gloeosporioides isolates.