Patterns of Xylella fastidiosa Colonization on the Precibarium of Sharpshooter Vectors Relative to Transmission to Plants
Patterns of Xylella fastidiosa Colonization on the Precibarium of Sharpshooter Vectors Relative to Transmission to Plants
复制标题
苛养木杆菌在神枪手载体上的定殖模式相对于向植物的传播
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
A. Purcell
中科院分区：
文献类型：
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作者：
R. Almeida;A. Purcell
苛养木杆菌是一种细菌性植物病原菌，可引起葡萄皮尔斯病等多种植物病害。神枪手叶蝉（半翅目：叶蝉科：叶蝉亚科）载体将这种细菌传播给植物。虽然病原体传播的基本机制还不完全清楚，但以前的研究表明，受感染昆虫的前肠是细菌接种物的来源，因为感染性真菌在蜕皮后具有传播性，并且传播不需要潜伏期。扫描电子显微镜记录了X射线的空间分布。fastidiosa的神枪手Graphocephala atropunctata（Signoret）的前肠后短（1-d）和长（4-d）收购访问期感染的植物和葡萄测试植物的各种接种访问期。在1天采集和1天接种期后，细胞仅在探针和cibarial泵之间的沉淀部分定植，通常嵌入基质样材料中。经过长时间（15天）的收购后，我们发现细菌细胞附着极性昆虫的角质层在整个precibarium规则的模式，但没有从特定的位置上的两个咽。在长时间采集后2周取样用于显微镜检查的昆虫，其口器中含有细菌传播X。fastidiosa到健康的葡萄藤独立的收购访问期的长度。与此相反，没有细菌的个体不会传播病原体。在连续的短时间采集和接种后，12个X. Fastidiosa阳性的昆虫没有传播到植物。我们还用神枪手Homalodisca coagulata做了传播实验;然而，30个个体中只有一个有X。fastidiosa附着在它的precibarium，没有传输到植物。我们的研究结果表明，神枪手引入植物X。在进食过程中从前鳃管脱离的苛养细胞。
Abstract Xylella fastidiosa is a bacterial plant pathogen that causes many plant diseases, including Pierce’s disease of grapevines. Sharpshooter leafhopper (Hemiptera: Cicadellidae: Cicadellinae) vectors transmit this bacterium to plants. Although the basic mechanism of pathogen transmission is not completely understood, previous studies implicated the foregut of infected insects as the source of bacterial inoculum because infective nymphs lose transmissibility after molting and no latent period is required for transmission. Scanning electron microscopy documented the spatial distribution of X. fastidiosa in the foreguts of the sharpshooter Graphocephala atropunctata (Signoret) after short (1-d) and long (4-d) acquisition access periods on infected plants and various inoculation access periods on grape test plants. After 1-d acquisition and 1-d inoculation periods, cells had only colonized portions of the precibarium between the stylets and the cibarial pump, often embedded in a matrix-like material. After long (15-d) periods after acquisition, we found bacterial cells attached polarly to the insect’s cuticle in a regular pattern throughout the precibarium but absent from specific locations on both pharynges. Insects sampled for microscopy 2 wk after long acquisition access periods and that contained bacteria in their mouthparts transmitted X. fastidiosa to healthy grapevines independently of the length of the acquisition access period. In contrast, individuals free of bacteria on the precibarium did not transmit the pathogen. After successive short acquisition and inoculation periods, 5 of 12 X. fastidiosa-positive insects did not transmit to plants. We also did transmission experiments with the sharpshooter Homalodisca coagulata; however, only one of 30 individuals had X. fastidiosa attached to its precibarium, and none transmitted it to plants. Our results suggest that sharpshooters introduce into plants X. fastidiosa cells that detach from the precibarial canal during feeding.