Apoptosis is generally considered the first line of defense against viral infection. However, the role of apoptosis in the interactions between plant viruses and their insect vectors has rarely been investigated. By studying plant DNA viruses of the genus Begomovirus within the family Geminiviridae, which are transmitted by whiteflies of the Bemisia tabaci species complex in a persistent manner, we revealed that virus-induced apoptosis in insect vectors can facilitate viral accumulation and transmission. We found that infection with tomato yellow leaf curl virus activated the apoptosis pathway in B. tabaci. Suppressing apoptosis by inhibitors or silencing caspase-3 significantly reduced viral accumulation, while the activation of apoptosis increased viral accumulation in vivo. Moreover, the positive effect of whitefly apoptosis on virus accumulation and transmission was not due to its cross talk with the autophagy pathway that suppresses begomovirus infection in whiteflies. We further showed that viral replication, rather than the viral coat protein, is likely the critical factor in the activation of apoptosis by the virus. These novel findings indicate that similarly to many animal and a few plant RNA viruses, plant DNA viruses may activate apoptosis in their insect vectors leading to enhanced viral accumulation and transmission.

中文翻译：

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Begomovirus 激活的粉虱载体中的细胞凋亡增强了病毒传播。

细胞凋亡通常被认为是抵御病毒感染的第一道防线。然而，很少有人研究细胞凋亡在植物病毒与其昆虫载体之间相互作用中的作用。通过研究Geminiviridae家族中Begomovirus属的植物 DNA 病毒，这些病毒由粉虱属的粉虱以持续方式传播，我们发现昆虫载体中病毒诱导的细胞凋亡可以促进病毒的积累和传播。我们发现番茄黄叶卷曲病毒感染激活了烟粉虱的凋亡途径。通过抑制剂抑制细胞凋亡或沉默caspase-3显着减少病毒积累，而细胞凋亡的激活增加了体内病毒的积累。此外，粉虱凋亡对病毒积累和传播的积极影响并不是因为它与抑制粉虱中 begomovirus 感染的自噬途径发生了交互作用。我们进一步表明，病毒复制，而不是病毒外壳蛋白，可能是病毒激活细胞凋亡的关键因素。这些新发现表明，与许多动物和少数植物 RNA 病毒类似，植物 DNA 病毒可能会激活其昆虫载体中的细胞凋亡，从而导致病毒积累和传播增强。