The miR-9b microRNA mediates dimorphism and development of wing in aphids
Feng Shang, Jinzhi Niu, Bi-Yue Ding, Wei Zhang, Dan-Dan Wei, Dong Wei, Hong-Bo Jiang, Jin-Jun Wang
西南大学植物保护学院教授王进军带领团队发现小分子RNA介导生物胁迫因子调控蚜虫翅型分化与翅发育的分子机制，研究结果有利于寻获新的小分子RNA控制剂靶标，为蚜虫类害虫防控提供新的思路。相关研究成果日前发表在《美国科学院院刊》上。
翅型分化是蚜虫对不良栖息环境的适应，蚜虫通过提高飞行能力使其逃离不良环境并找到新的栖息地，多种蚜虫在种群密度过大时存在跨代翅型分化现象。miRNA作为重要的后转录调控因子，能否介导高种群密度诱导产生的蚜虫翅型分化及其调控网络尚不清楚。
团队以褐色桔蚜（Aphis citricidus）和豌豆蚜（Acyrthosiphon pisum）为研究对象，探讨miRNA在蚜虫翅型分化和翅发育过程中的重要作用。研究鉴定到在翅型分化和翅发育过程中唯一下调的miRNA（miR-9b），其靶向调控ABC（ATP-binding cassette）转运蛋白（ABCG4）；低种群密度下，抑制miR-9b的表达显著增加后代有翅率；而在高种群密度下，过表达miR-9b则会降低后代有翅率。此外，在翅发育过程中过表达miR-9b则会导致翅发育畸形；最后，研究发现miR-9b通过调节胰岛素信号通路活性进而影响蚜虫的翅型分化。
研究结果拓展了miRNA作为环境因子的信号“传递介质”调控昆虫表型可塑性的分子机理。
来源：中国科学报 张晴丹
Abstract
Wing dimorphism is a phenomenon of phenotypic plasticity in aphid dispersal. However, the signal transduction for perceiving environmental cues (e.g., crowding) and the regulation mechanism remain elusive. Here, we found that aci-miR-9b was the only down-regulated microRNA (miRNA) in both crowding-induced wing dimorphism and during wing development in the brown citrus aphid Aphis citricidus. We determined a targeted regulatory relationship between aci-miR-9b and an ABC transporter (AcABCG4). Inhibition of aci-miR-9b increased the proportion of winged offspring under normal conditions. Overexpression of aci-miR-9b resulted in decline of the proportion of winged offspring under crowding conditions. In addition, overexpression of aci-miR-9b also resulted in malformed wings during wing development. This role of aci-miR-9b mediating wing dimorphism and development was also confirmed in the pea aphid Acyrthosiphon pisum. The downstream action of aci-miR-9b-AcABCG4 was based on the interaction with the insulin and insulin-like signaling pathway. A model for aphid wing dimorphism and development was demonstrated as the following: maternal aphids experience crowding, which results in the decrease of aci-miR-9b. This is followed by the increase of ABCG4, which then activates the insulin and insulin-like signaling pathway, thereby causing a high proportion of winged offspring. Later, the same cascade, “miR-9b-ABCG4-insulin signaling,” is again involved in wing development. Taken together, our results reveal that a signal transduction cascade mediates both wing dimorphism and development in aphids via miRNA. These findings would be useful in developing potential strategies for blocking the aphid dispersal and reducing viral transmission.
