Data from: Manipulation of light spectral quality disrupts host location and attachment by parasitic plants in the genus Cuscuta

Parasitic plants in the genus Cuscuta (dodders) make their living by extracting resources from other plants. While relatively few dodder species are agricultural pests, those that are can be challenging to control, in part due to their intimate physical and physiological association with host plants. Consequently, dodders remain pervasive and economically damaging pests in a variety of crop systems. The development of improved management strategies would be facilitated by greater understanding of the ecological and environmental factors that influence the establishment and perpetuation of dodder infestations. Light cues play an important role in dodder host location and attachment. To better understand the influence of light conditions on parasite ecology, and potential implications for management, we examined how manipulating the ratio of red to far-red wavelengths (R:FR), via both passive filtering of natural sunlight and active spectral manipulation using LEDs, affects host location and host attachment by two dodder species (C. campestris on tomato hosts and C. gronovii on jewelweed). For both host-parasite combinations, host location and subsequent attachment by dodder parasites was dramatically reduced in high R:FR environments compared to control conditions (with R:FR characteristic of sunlight) and low R:FR conditions. Circumnutation by dodder seedlings was also significantly faster under high R:FR. We observed short-term effects of high R:FR on the height and dry mass of tomato host plants (immediately following 7-day exposure), as well as changes in tomato volatile emissions. However, preliminary investigation of long-term effects on host plants suggests that short-term exposure to high R:FR (i.e. during the critical period when dodder seedlings emerge and attach to hosts) has little or no effect on host plant size or fruit yield at the time of harvest. Synthesis and applications. Our findings suggest that spectral manipulation during the early stages of crop plant growth (e.g. via light-filtering row covers), may have significant potential to augment existing methods for managing or preventing dodder infestations in agricultural crops. We discuss potential obstacles to the realization of its potential, as well as next steps toward the development and optimization of spectral manipulation methods for use in agroecosystems.菟丝子属（Cuscuta，dodders）的寄生植物，通过从其他植物体内获取营养物质维持生存。尽管危害农业的菟丝子物种数量相对较少，但这类有害生物往往难以防控，其部分原因在于它们与宿主植物之间存在紧密的物理与生理关联。正因如此，菟丝子仍是多种作物种植系统中分布广泛且造成显著经济损失的有害生物。若要开发更为高效的防治策略，亟需深入解析影响菟丝子侵染定殖与持续蔓延的生态与环境因子。光信号在菟丝子定位宿主并完成附着的过程中扮演着关键角色。为进一步阐明光照条件对寄生生态学的影响，以及其在实际防治中的潜在应用价值，本研究通过两种方式调控红光与远红光波长比值（R:FR）：一是对自然光进行被动过滤，二是利用发光二极管（LED）开展主动光谱调控，以此探究该比值对两种菟丝子——寄生番茄的田野菟丝子（C. campestris）、寄生凤仙花的格氏菟丝子（C. gronovii）——的宿主定位与附着行为的影响。实验结果显示，相较于以自然光特征为对照的对照组与低R:FR组，高R:FR环境下，两种宿主-寄生组合的菟丝子均大幅降低了宿主定位与后续附着的成功率。同时，高R:FR条件下菟丝子幼苗的回旋生长速率也显著提升。此外，本研究观测到，经7天短期暴露后，高R:FR会对番茄宿主植株的株高与干重产生影响，同时改变番茄的挥发性挥发物组成。不过，针对宿主长期影响的初步调查显示，在菟丝子幼苗萌发并附着宿主的关键时期，短期暴露于高R:FR环境，对收获期宿主植株的株型大小或果实产量几乎无影响。综合与应用。本研究结果表明，在作物生长早期通过光谱调控手段（例如使用滤光型田间覆盖物），或可有效辅助现有防治手段，减轻或阻止农业作物中的菟丝子侵染。本文还讨论了实现该技术潜力可能面临的潜在障碍，以及面向农业生态系统开发并优化光谱调控方法的后续研究方向。