Vaisman Michael, Hak Hagit, Arazi Tzahi, Spiegelman Ziv
Department of Plant Pathology and Weed Research, Agricultural Research Organization-The Volcani Institute, 68 HaMaccabim Road, P.O.B 15159, Rishon LeZion 7505101, Israel.
The Robert H. Smith Faculty of Agriculture, Food and Environment, the Hebrew University of Jerusalem, PO Box 12, Rehovot 761001, Israel.
Plant Cell Physiol. 2023 Jan 30;63(12):1980-1993. doi: 10.1093/pcp/pcab179.
Plant viruses cause systemic diseases that severely impair plant growth and development. While the accumulation of viruses in the root system has long been established, little is known as to how viruses affect root architecture. Here, we examined how the emerging tobamovirus, tomato brown rugose fruit virus (ToBRFV), alters root development in tomato. We found that ToBRFV and tobacco mosaic virus both invaded root systems during the first week of infection. ToBRFV infection of tomato plants resulted in a significant decrease in root biomass and elongation and root-to-shoot ratio and a marked suppression of root branching. Mutation in RNA-dependent RNA polymerase 6 increased the susceptibility of tomato plants to ToBRFV, resulting in severe reduction of various root growth parameters including root branching. Viral root symptoms were associated with the accumulation of auxin response factor 10a (SlARF10a) transcript, a homolog of Arabidopsis ARF10, a known suppressor of lateral root development. Interestingly, loss-of-function mutation in SlARF10a moderated the effect of ToBRFV on root branching. In contrast, downregulation of sly-miR160a, which targets SlARF10a, was associated with constitutive suppression root branching independent of viral infection. In addition, overexpression of a microRNA-insensitive mutant of SlARF10a mimicked the effect of ToBRFV on root development, suggesting a specific role for SlARF10a in ToBRFV-mediated suppression of root branching. Taken together, our results provide new insights into the impact of tobamoviruses on root development and the role of ARF10a in the suppression of root branching in tomato.
植物病毒会引发系统性疾病，严重损害植物的生长和发育。虽然病毒在根系中的积累早已得到证实，但关于病毒如何影响根系结构却知之甚少。在此，我们研究了新出现的烟草花叶病毒属病毒——番茄褐色皱纹果病毒（ToBRFV）如何改变番茄的根系发育。我们发现，ToBRFV和烟草花叶病毒在感染的第一周都会侵入根系。ToBRFV感染番茄植株会导致根生物量、根伸长和根冠比显著降低，并显著抑制根分支。RNA依赖的RNA聚合酶6发生突变会增加番茄植株对ToBRFV的易感性，导致包括根分支在内的各种根系生长参数严重降低。病毒引起的根系症状与生长素响应因子10a（SlARF10a）转录本的积累有关，SlARF10a是拟南芥ARF10的同源物，已知是侧根发育的抑制因子。有趣的是，SlARF10a功能缺失突变减轻了ToBRFV对根分支的影响。相反，靶向SlARF10a的sly-miR160a下调与不依赖病毒感染的组成型根分支抑制有关。此外，SlARF10a的一个对微RNA不敏感的突变体的过表达模拟了ToBRFV对根系发育的影响，表明SlARF10a在ToBRFV介导的根分支抑制中具有特定作用。综上所述，我们的研究结果为烟草花叶病毒属病毒对根系发育的影响以及ARF10a在番茄根分支抑制中的作用提供了新的见解。
