Three Melanin Pathway Genes, TH, yellow, and aaNAT, Regulate Pigmentation in the Twin-Spotted Assassin Bug, Platymeris biguttatus (Linnaeus)
Three Melanin Pathway Genes, TH, yellow, and aaNAT, Regulate Pigmentation in the Twin-Spotted Assassin Bug, Platymeris biguttatus (Linnaeus)
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三个黑色素途径基因，TH、黄色和 aaNAT，调节双斑刺客蝽 Platymeris biguttatus (Linnaeus) 的色素沉着
DOI：
10.3390/ijms20112728
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发表时间：
2019-06-01
影响因子：
5.6
通讯作者：
Cai, Wanzhi
中科院分区：
文献类型：
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作者：
Zhang, Yinqiao;Li, Hu;Cai, Wanzhi
色素沉着在昆虫的生存和繁殖中起着至关重要的作用。在全变异昆虫中研究了许多黑色素通路基因；然而，它们只在两个半代谢昆虫属，Oncopeltus和Periplaneta中被研究过。本研究利用RNA干扰（RNAi）技术分析了另一种半代谢昆虫，即双斑刺客蝽（Platymeris bigutatus）的三个黑色素通路基因（TH、yellow和aaNAT）。TH在刚蜕皮的若虫和成虫中高度表达。TH RNAi导致黑色色素完全丧失，保留黄色。因此，这种刺客虫的黑色色素仅由黑色素途径产生，而黄色色素则由其他未知的色素沉着途径产生。黄、aaNAT在鞘翅白斑高度表达。下调黄色导致高死亡率的棕色表型，表明黄色在角质层形成和黑色素从棕色到黑色的转化过程中起重要作用。有趣的是，aaNAT RNAi不仅导致白色色素的丢失，还导致黄色和红色色素的丢失。这种aaNAT表型在其他昆虫中未见报道。我们的结果为理解黑色素通路提供了新的信息，其中aaNAT对无色图案的形成至关重要。
Pigmentation plays a vital role in insect survival and reproduction. Many melanin pathway genes have been studied in holometabolous insects; however, they have only been studied in two hemimetabolous insect genera, Oncopeltus and Periplaneta. Here we analyzed three melanin pathway genes (TH, yellow, and aaNAT) using RNA interference (RNAi) in another hemimetabolous insect, namely the twin-spotted assassin bug, Platymeris biguttatus. TH was highly expressed in freshly molted nymphs and adults. TH RNAi resulted in a complete loss of black pigment, with yellow coloration maintained. Therefore, black pigment in this assassin bug is solely generated from the melanin pathway, whereas yellow pigment is generated from other unknown pigmentation pathways. yellow and aaNAT were highly expressed in the white spot of the hemelytra. Downregulation of yellow caused a brown phenotype with high mortality, indicating an important role of yellow functions in cuticle formation and in the process of converting melanin from brown to black. Interestingly, aaNAT RNAi caused not only loss of white pigment, but also loss of yellow and red pigments. This phenotype of aaNAT has not been reported in other insects. Our results provide new information for understanding the melanin pathway in which aaNAT is essential for the formation of colorless patterns.