Table_1_Virus-virus interactions alter the mechanical transmissibility and host range of begomoviruses.docx

IntroductionBegomoviruses are mainly transmitted by whiteflies. However, a few begomoviruses can be transmitted mechanically. Mechanical transmissibility affects begomoviral distribution in the field.
Materials and methodsIn this study, two mechanically transmissible begomoviruses, tomato leaf curl New Delhi virus-oriental melon isolate (ToLCNDV-OM) and tomato yellow leaf curl Thailand virus (TYLCTHV), and two nonmechanically transmissible begomoviruses, ToLCNDV-cucumber isolate (ToLCNDV-CB) and tomato leaf curl Taiwan virus (ToLCTV), were used to study the effects of virus-virus interactions on mechanical transmissibility.
ResultsNicotiana benthamiana and host plants were coinoculated through mechanical transmission with inoculants derived from plants that were mix-infected or inoculants derived from individually infected plants, and the inoculants were mixed immediately before inoculation. Our results showed that ToLCNDV-CB was mechanically transmitted with ToLCNDV-OM to N. benthamiana, cucumber, and oriental melon, whereas ToLCTV was mechanically transmitted with TYLCTHV to N. benthamiana and tomato. For crossing host range inoculation, ToLCNDV-CB was mechanically transmitted with TYLCTHV to N. benthamiana and its nonhost tomato, while ToLCTV with ToLCNDV-OM was transmitted to N. benthamiana and its nonhost oriental melon. For sequential inoculation, ToLCNDV-CB and ToLCTV were mechanically transmitted to N. benthamiana plants that were either preinfected with ToLCNDV-OM or TYLCTHV. The results of fluorescence resonance energy transfer analyses showed that the nuclear shuttle protein of ToLCNDV-CB (CBNSP) and the coat protein of ToLCTV (TWCP) localized alone to the nucleus. When coexpressed with movement proteins of ToLCNDV-OM or TYLCTHV, CBNSP and TWCP relocalized to both the nucleus and the cellular periphery and interacted with movement proteins.
DiscussionOur findings indicated that virus-virus interactions in mixed infection circumstances could complement the mechanical transmissibility of nonmechanically transmissible begomoviruses and alter their host range. These findings provide new insight into complex virus-virus interactions and will help us to understand the begomoviral distribution and to reevaluate disease management strategies in the field.

引言
双生病毒（Begomoviruses）主要由烟粉虱传播，但少数双生病毒可通过机械方式传播。机械传播特性会影响双生病毒在田间的分布。

材料与方法
本研究选取2种可机械传播的双生病毒：番茄曲叶新德里病毒东方甜瓜分离物（ToLCNDV-OM）与番茄黄化曲叶泰国病毒（TYLCTHV），以及2种非机械传播的双生病毒：番茄曲叶新德里病毒黄瓜分离物（ToLCNDV-CB）与番茄曲叶台湾病毒（ToLCTV），用以探究病毒-病毒互作对机械传播能力的影响。
实验通过机械接种方式，分别使用混合侵染植株制备的接种物、以及单独侵染植株制备的接种物（接种前即刻混合），对本氏烟（Nicotiana benthamiana）及其宿主植物进行共接种。
结果显示，ToLCNDV-CB可与ToLCNDV-OM共同通过机械传播侵染本氏烟、黄瓜及东方甜瓜；而ToLCTV可与TYLCTHV共同通过机械传播侵染本氏烟与番茄。
在跨宿主范围接种实验中，ToLCNDV-CB可与TYLCTHV共同侵染本氏烟及其非宿主番茄；ToLCTV与ToLCNDV-OM则可共同侵染本氏烟及其非宿主东方甜瓜。
序贯接种实验结果表明，预先被ToLCNDV-OM或TYLCTHV侵染的本氏烟植株，可被机械接种ToLCNDV-CB与ToLCTV成功侵染。
荧光共振能量转移（Fluorescence Resonance Energy Transfer, FRET）分析结果显示：ToLCNDV-CB的核穿梭蛋白（CBNSP）与ToLCTV的外壳蛋白（TWCP）仅定位于细胞核；当与ToLCNDV-OM或TYLCTHV的运动蛋白共表达时，CBNSP与TWCP会重新定位于细胞核与细胞外周，并与运动蛋白发生互作。

讨论
本研究结果表明，混合侵染情境下的病毒-病毒互作，可互补非机械传播双生病毒的机械传播能力，并改变其宿主范围。上述发现为复杂的病毒-病毒互作研究提供了新视角，有助于深入理解双生病毒的田间分布规律，同时为重新评估田间病害管理策略提供参考。