Patt Joseph M, Meikle William G, Niedz Randall P, Woods Daniel
USDA-ARS U.S. Horticultural Research Laboratory, Fort Pierce, FL, United States.
USDA-ARS Carl Hayden Bee Research Center, Tucson, AZ, United States.
Front Plant Sci. 2018 Dec 20;9:1891. doi: 10.3389/fpls.2018.01891. eCollection 2018.
There is interest in using ligands of chemosensory binding proteins (CBP) to augment an insect's responsiveness to chemosensory cues. We showed previously that combining a synthetic ligand of a CBP with limonene, a common citrus volatile, enhanced the probing response of Asian citrus psyllid ( ). Here, we determined whether synthetic compounds, which were ligands of . olfactory binding protein (OBP) DCSAP4, influenced the settling and aggregation levels of psyllids on young citrus shoots. The test ligands and Cmac scent were dispensed from a droplet of an emulsified wax product (SPLAT) placed on the bottom of each vial. The shoots were presented: (1) alone (shoot + blank SPLAT), (2) with a mixture of citrus volatiles ("Cmac scent") (shoot + SPLAT with Cmac scent), or (3) with different concentrations of test ligands (shoot + SPLAT with test ligand at concentration 1, shoot + SPLAT with test ligand at concentration 2, etc.). Depending on the availability of test ligands, sprigs, and psyllids, each test included from two to four replicates of each treatment (i.e., shoot only, shoot + Cmac scent, shoot + test ligand at concentration 1, shoot + test ligand at concentration 2, etc.); only a single test ligand was presented in each test. For each test, 200 were released in the test area and the numbers of psyllids on each sprig were counted 24 h later. Sprigs with ≥7 psyllids were considered to be an aggregation. A total of seven ligands were tested individually. Four of the ligands (654, 717, 784, and 861) modulated psyllid settling and aggregation response, causing greater settling and aggregation to sprigs presented with the Cmac scent than to those sprigs with blank SPLAT. Presentation of one of the ligands (019) resulted in an opposite effect in which psyllid settling and aggregation levels were lower on sprigs with Cmac scent than on those with blank SPLAT. There were no differences in settling levels in the different treatment vials in the Ligand 905 experiment. In the Ligand 937 experiment, settling levels did not vary significantly between treatment vials although settling levels were relatively high in all treatment vials and there was a significant treatment effect. Increased settling and aggregation levels were largely not observed with in the vials with only the test ligands, and there was little effect of ligand concentration on psyllid response levels. This suggests that the test ligands themselves did not attract the psyllids but rather modulated the psyllid's response to the Cmac scent. The results suggest that synthetic ligands of . CBPs can be used to increase the effectiveness of citrus scent lures used to attract psyllids to monitoring traps and attract and kill devices.
人们对使用化学感应结合蛋白（CBP）的配体来增强昆虫对化学感应线索的反应能力很感兴趣。我们之前表明，将一种CBP的合成配体与柠檬烯（一种常见的柑橘挥发物）相结合，可增强亚洲柑橘木虱的探测反应。在这里，我们确定了作为嗅觉结合蛋白（OBP）DCSAP4配体的合成化合物是否会影响木虱在柑橘嫩梢上的栖息和聚集水平。测试配体和Cmac气味剂通过放置在每个小瓶底部的一滴乳化蜡产品（SPLAT）进行分配。嫩梢的呈现方式如下：（1）单独呈现（嫩梢 + 空白SPLAT），（2）与柑橘挥发物混合物（“Cmac气味剂”）一起呈现（嫩梢 + 含有Cmac气味剂的SPLAT），或（3）与不同浓度的测试配体一起呈现（嫩梢 + 浓度为1的测试配体的SPLAT，嫩梢 + 浓度为2的测试配体的SPLAT等）。根据测试配体、嫩梢和木虱的可得情况，每个测试对每种处理（即仅嫩梢、嫩梢 + Cmac气味剂、嫩梢 + 浓度为1的测试配体、嫩梢 + 浓度为2的测试配体等）进行两到四次重复；每次测试仅呈现一种测试配体。对于每次测试，在测试区域释放200只木虱，并在24小时后统计每个嫩梢上的木虱数量。有≥7只木虱的嫩梢被视为聚集情况。总共单独测试了七种配体。其中四种配体（654、717、784和861）调节了木虱的栖息和聚集反应，导致与含有空白SPLAT的嫩梢相比，含有Cmac气味剂的嫩梢上有更多的木虱栖息和聚集。呈现其中一种配体（019）产生了相反的效果，即含有Cmac气味剂的嫩梢上的木虱栖息和聚集水平低于含有空白SPLAT的嫩梢。在配体905实验中，不同处理小瓶中的栖息水平没有差异。在配体937实验中，尽管所有处理小瓶中的栖息水平相对较高且存在显著的处理效应，但处理小瓶之间的栖息水平没有显著差异。在仅含有测试配体的小瓶中，基本上未观察到栖息和聚集水平的增加，并且配体浓度对木虱反应水平的影响很小。这表明测试配体本身并不会吸引木虱，而是调节了木虱对Cmac气味剂的反应。结果表明，CBP的合成配体可用于提高用于吸引木虱到监测诱捕器以及吸引和捕杀装置的柑橘气味诱饵的有效性。
