PDF(Pubmed)
Abstract：
Aphids are the most common insect vector transmitting hundreds of plant viruses. Aphid wing dimorphism (winged vs. wingless) not only showcases the phenotypic plasticity but also impacts virus transmission; however, the superiority of winged aphids in virus transmission over the wingless morph is not well understood. Here, we show that plant viruses were efficiently transmitted and highly infectious when associated with the winged morph of Myzus persicae and that a salivary protein contributed to this difference. The carbonic anhydrase II (CA-II) gene was identified by RNA-seq of salivary glands to have higher expression in the winged morph. Aphids secreted CA-II into the apoplastic region of plant cells, leading to elevated accumulation of H+. Apoplastic acidification further increased the activities of polygalacturonases, the cell wall homogalacturonan (HG)-modifying enzymes, promoting degradation of demethylesterified HGs. In response to apoplastic acidification, plants accelerated vesicle trafficking to enhance pectin transport and strengthen the cell wall, which also facilitated virus translocation from the endomembrane system to the apoplast. Secretion of a higher quantity of salivary CA-II by winged aphids promoted intercellular vesicle transport in the plant. The higher vesicle trafficking induced by winged aphids enhanced dispersal of virus particles from infected cells to neighboring cells, thus resulting in higher virus infection in plants relative to the wingless morph. These findings imply that the difference in the expression of salivary CA-II between winged and wingless morphs is correlated with the vector role of aphids during the posttransmission infection process, which influences the outcome of plant endurance of virus infection.
摘要：
蚜虫是传播数百种植物病毒的最常见昆虫媒介。蚜虫翅膀二态性（有翅膀与无翼)不仅展示了表型可塑性，而且还影响病毒传播；然而，有翼蚜虫在病毒传播中优于无翼形态的优势尚不清楚。这里,我们表明，当与桃树的翅形态相关时，植物病毒可以有效传播并具有高度传染性，并且唾液蛋白促成了这种差异。通过唾液腺的RNA-seq鉴定出碳酸酐酶II（CA-II）基因在有翼形态中具有较高的表达。蚜虫将CA-II分泌到植物细胞的质外生区，导致H+积累增加。共生酸化进一步增加了多聚半乳糖醛酸酶的活性，细胞壁高半乳糖醛酸（HG）修饰酶，促进去甲酯化HGs的降解。为了应对脱原酸化，植物加速囊泡运输，以增强果胶运输和加强细胞壁，这也促进了病毒从内膜系统转移到质外体。有翼蚜虫分泌更多的唾液CA-II促进了植物中细胞间的囊泡运输。有翼蚜虫诱导的更高的囊泡运输增强了病毒颗粒从感染细胞向邻近细胞的扩散，因此，相对于无翼形态，植物中的病毒感染更高。这些发现表明，有翼和无翼变体之间唾液CA-II表达的差异与蚜虫在传播后感染过程中的载体作用有关，这影响了植物对病毒感染的耐受性。
