Bruton B D, Fletcher J, Pair S D, Shaw M, Sittertz-Bhatkar H
United States Department of Agriculture, Agricultural Research Service (USDA-ARS), Lane, Oklahoma 74555.
Department of Plant Pathology, Oklahoma State University, Stillwater 74078.
Plant Dis. 1998 May;82(5):512-520. doi: 10.1094/PDIS.1998.82.5.512.
Since 1991, a new disease of cucurbits in central Texas and Oklahoma, designated yellow vine, has resulted in the decline and plant death of watermelon, cantaloupe, squash, and pumpkin. Affected plants are characterized by leaf yellowing, phloem discoloration, and plant collapse. Year-to-year variation in disease incidence has ranged from spotty outbreaks to complete crop loss in early-planted watermelon fields. A systematic investigation to determine the causal agent of the disease included pathogen isolation attempts, transmission tests, serological assays with various antisera (enzyme-linked immunosorbent assay and Western blotting), and DNA hybridizations with selected probes (dot and Southern blots). None of these tests revealed a consistent relationship between the expression of yellow vine symptoms and the presence of a particular microorganism or virus in the plant. However, transmission electron microscopic examination showed the consistent presence of a bacterium in the phloem sieve elements of symptomatic plants. The rod-shaped bacteria, observed only in symptomatic cucurbits, measured 0.25 to 0.5 μm in width and 1.0 to 3.0 μm in length and were surrounded by a triple-layered cell envelope.
自1991年以来，得克萨斯州中部和俄克拉何马州的葫芦科作物出现了一种新病害，称为黄藤病，导致西瓜、甜瓜、南瓜和西葫芦减产并植株死亡。受影响的植株表现为叶片发黄、韧皮部变色和植株枯萎。病害发生率逐年变化，从局部爆发到早播西瓜田的完全绝收。一项确定该病病原体的系统调查包括病原体分离尝试、传播试验、用各种抗血清进行的血清学检测（酶联免疫吸附测定和蛋白质印迹法）以及与选定探针的DNA杂交（斑点杂交和Southern杂交）。这些测试均未揭示黄藤病症状的表现与植物中特定微生物或病毒的存在之间存在一致关系。然而，透射电子显微镜检查显示，有症状植株的韧皮部筛管细胞中始终存在一种细菌。这种杆状细菌仅在有症状的葫芦科作物中观察到，宽度为0.25至0.5μm，长度为1.0至3.0μm，被三层细胞包膜包围。
