The Early Dodder Gets the Host: Decoding the Coiling Patterns of Cuscuta campestris with Automated Image Processing

Cuscuta spp., (dodder) is a rootless and leafless parasitic plant posing significant agricultural challenges. In this study, we aimed to elucidate the dynamics of the coiling patterns in Cuscuta campestris and examine the role of circadian rhythms in its host-seeking ability. Using time-lapse photography, we recorded the circumnutation and coiling movements of C. campestris at different inoculation times on non-living hosts. Subsequent image analyses were facilitated through an in-house Python-based image analysis pipeline. We observed that the coiling efficacy of C. campestris varied with the inoculation time of day, showing higher success and faster initiation in morning than in evening. These observations suggest that Cuscuta , despite lacking leaves and a developed chloroplast, can discern photoperiod changes, which significantly determine its parasitic efficiency. The automated image analysis confirmed the reliability of our Python pipeline, aligning closely with manual annotations. This study provides significant insights into the parasitic strategies of C. campestris and demonstrates the potential of integrating computational image analysis in plant biology for exploring complex plant behaviors. Furthermore, this method provides an efficient tool for investigating plant movement dynamics, laying the foundation for future studies on mitigating the economic impacts of parasitic plants. ### Competing Interest Statement The authors have declared no competing interest.