柑橘衰退病毒含量对其蚜传效率的影响

为明确毒源植株和蚜虫中柑橘衰退病毒(Citrus tristeza virus,CTV)的发生情况与蚜虫传播CTV能力的关系,将褐色橘蚜、棉蚜、橘二叉蚜和绣线菊蚜置于分别感染了4个CTV分离株的锦橙上取食24 h后,运用巢式RT-PCR和实时RT-PCR检测蚜虫和锦橙的带毒情况,并分析蚜虫的传毒能力。结果显示,蚜虫中CTV的平均带毒率为0.76~0.84,其中棉蚜的最高,其次为绣线菊蚜、褐色橘蚜和橘二叉蚜。锦橙中各CTV分离株的含量差异不大,与蚜虫传毒效率间无显著相关性;也未发现蚜虫带毒率与其传播CTV能力之间存在相关性。蚜虫体内CTV的含量为5.36×103±2.33×103~2.01×106±3.67×105拷贝,褐色橘蚜中含量最高,其次为棉蚜、橘二叉蚜和绣线菊蚜;且高蚜传能力CTV分离株在褐色橘蚜体内的含量远高于低蚜传能力分离株。表明蚜虫体内CTV的含量可能与蚜虫传毒能力有关。

Influences of the quantity of Citrus tristeza virus on transmissibility by different aphid species

Citrus tristeza virus (CTV) is transmitted in a semi-persistent manner by several aphid species. In this study, four CTV isolates were detected in single Toxoptera citricida, Aphis gossypii, T.aurantii and A.citricola with frequency of 0.76-0.84 by nested RT-PCR after 24 h acquisition access period. CTV detection rates in A.gossypii were the highest, followed by A.citricola, T.citricida and T.aurantii, respectively. These results suggested that CTV is acquired by different aphid species regardless of their transmissibility. Analysis by real-time RT-PCR showed that the amount of CTV in Jincheng sweet orange was similar and no obvious relationship between transmissibility and CTV accumulation in Jincheng sweet orange was found. The number of CTV-targets in aphids ranged from 5.36×10³±2.33×10³ to 2.01×10⁶±3.67×10⁵. As the most efficient vector to CTV, most copies of CTV-targets were detected in single viruliferous T. citricida, followed by A.gossypii, T.aurantii and A.citricola, respectively. Furthermore, CTV isolates with high transmissibility were present with much more particles in single T.citricida than isolates with low transmissibility. The quantity of CTV in aphids may play a role in aphid transmission.