Medrano Enrique Gino, Esquivel Jesus, Bell Alois, Greene Jeremy, Roberts Phillip, Bacheler Jack, Marois James, Wright David, Nichols Robert, Lopez Juan
Cotton Pathology Research Unit, United States Department of Agriculture-Agricultural Research Service (USDA-ARS), College Station, TX, USA.
Curr Microbiol. 2009 Oct;59(4):405-12. doi: 10.1007/s00284-009-9452-5. Epub 2009 Jul 28.
Recently, we showed that the southern green stink bug (SGSB), Nezara viridula (L.), can transmit Pantoea agglomerans (Ewing and Fife), an opportunistic bacterium, into green cotton bolls resulting in plant disease. Here, we hypothesized that our established model could be used to determine if the SGSB was a general, non-discriminate vector by using two other opportunistic bacterial pathogens of bolls (Pantoea ananatis [Serano] and Klebsiella pneumoniae [Schroeter]) and the known fungal pathogen Nematospora coryli (Peglion). Variants of P. ananatis (strain Pa-1R) and K. pneumoniae (strain Kp 5-1R) selected for rifampicin (Rif) resistance were used as bacterial opportunists. N. coryli was detected only from laboratory-reared SGSB directly exposed to the fungus. Both Pa-1R and Kp 5-1R were recovered from SGSB previously provided a contaminated food source (2 days), sterile food (5 days), and then harvested after being caged on bolls (2 days) at levels reaching 10(3) and 10(4) colony forming units (cfus) per insect, respectively. However, bolls caged with insects infected with Pa-1R or Kp 5-1R and with evidence of feeding did not become diseased nor were either opportunists detected from boll tissues. Insects infected with N. coryli transmitted the pathogen, which resulted in diseased bolls and fungi concentrations reached 10(6) cfus/g locule tissue at 2 weeks following the caging period. Notably, each of the three pathogens independently caused boll disease when mechanically inoculated using a needle puncture. Generally, these results suggest that cotton pathogen acquisition by the SGSB was not sufficient to determine whether the insects were disease vectors of the opportunists.
最近，我们发现南方绿蝽（SGSB），即稻绿蝽（Nezara viridula (L.)），能够将一种机会性细菌——成团泛菌（Pantoea agglomerans (Ewing and Fife)）传播到绿色棉铃中，从而引发植物病害。在此，我们假设，通过使用棉铃的另外两种机会性细菌病原体（菠萝泛菌（Pantoea ananatis [Serano]）和肺炎克雷伯菌（Klebsiella pneumoniae [Schroeter]））以及已知的真菌病原体榛色链格孢（Nematospora coryli (Peglion)），我们建立的模型可用于确定南方绿蝽是否为一种普遍的、无选择性的传播媒介。选择对利福平（Rif）具有抗性的菠萝泛菌变体（菌株Pa - 1R）和肺炎克雷伯菌变体（菌株Kp 5 - 1R）作为细菌机会病原体。仅在直接接触该真菌的实验室饲养的南方绿蝽中检测到榛色链格孢。Pa - 1R和Kp 5 - 1R均从先前被提供受污染食物源（2天）、无菌食物（5天），然后在棉铃上关养（2天）后收获的南方绿蝽中回收，回收水平分别达到每只昆虫10³和10⁴菌落形成单位（cfu）。然而，用感染了Pa - 1R或Kp 5 - 1R且有取食迹象的昆虫关养的棉铃并未发病，且在棉铃组织中也未检测到这两种机会病原体。感染榛色链格孢的昆虫传播了该病原体，导致棉铃发病，在关养期2周后，真菌浓度达到每克子房组织10⁶ cfu。值得注意的是，当使用针刺进行机械接种时，这三种病原体中的每一种都能独立引发棉铃病害。总体而言，这些结果表明，南方绿蝽获取棉花病原体不足以确定这些昆虫是否为机会病原体的病害传播媒介。
