In The Plant journal : for cell and molecular biology
Brassinosteroids (BRs) are a group of plant steroid hormones involved in regulating growth, development, and stress responses. Many components of the BR pathway have previously been identified and characterized. However, BR phenotyping experiments are typically performed in a low-throughput manner, such as on petri plates. Additionally, the BR pathway affects drought responses, but drought experiments are time-consuming and difficult to control. To mitigate these issues and increase throughput, we developed the Robotic Assay for Drought (RoAD) system to perform BR and drought response experiments in soil-grown Arabidopsis plants. RoAD is equipped with a robotic arm, a rover, a bench scale, a precisely controlled watering system, an RGB camera, and a laser profilometer. It performs daily weighing, watering, and imaging tasks and is capable of administering BR response assays by watering plants with Propiconazole (PCZ), a BR biosynthesis inhibitor. We developed image processing algorithms for both plant segmentation and phenotypic trait extraction to accurately measure traits including plant area, plant volume, leaf length, and leaf width. We then applied machine learning algorithms that utilized the extracted phenotypic parameters to identify image-derived traits that can distinguish control, drought, and PCZ-treated plants. We carried out PCZ and drought experiments on a set of BR mutants and Arabidopsis accessions with altered BR responses. Finally, we extended the RoAD assays to perform BR response assays using PCZ in Zea mays (maize) plants. This study establishes an automated and non-invasive robotic imaging system as a tool to accurately measure morphological and growth-related traits of Arabidopsis and maize plants in three dimensions (3D), providing insights into the BR-mediated control of plant growth and stress responses.
Xiang Lirong, Nolan Trevor M, Bao Yin, Elmore Mitch, Tuel Taylor, Gai Jingyao, Shah Dylan, Wang Ping, Huser Nicole M, Hurd Ashley M, McLaughlin Sean A, Howell Stephen H, Walley Justin W, Yin Yanhai, Tang Lie
\nArabidopsis thaliana, 2D and 3D imaging, brassinosteroid, drought, leaf segmentation, phenotypic traits, plant growth