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This study presents a novel three-dimensional (3D) tool "3D in vitro choice" for chemotaxis assays with cyst nematodes. The original 3D in vitro choice was customized through digital printing. Freshly hatched second stage juveniles (J2s) of the cyst nematode Globodera pallida were used as the nematode model to illustrate chemo-orientation behavior in the 3D system. The efficiency and reliability of the 3D in vitro choice were validated with 2% Phytagel as navigation medium, in three biological assays and using tomato root exudates or potato root border cells and their associated mucilage as a positive attractant as compared with water. For each biological assay, J2s were hatched from the same population of a single generation glasshouse-cultured cysts. This novel easy to use and low-cost 3d-device could be a useful replacement to Petri dishes assays in nematode behavioral studies due to the ease of deposition of nematodes and test substances, coupled with its distinctive zones that allow for precision in choice making by the nematodes.

Background: Agronomical and plant physiological studies employ a large variety of compounds that impact root development. The effect of these compounds is often evaluated by root architecture analyses using dedicated software. During the past decade, a growing number of tools proposed complex and deep analysis of the root system architecture. While these software applications are often complex and require specific set up, here, we propose a simple method based on the most common tools used by biologists: ImageJ and Excel®.Results: First, roots are measured manually with ImageJ following a succession of operations (i. choose a plant; ii. Measure: a. the primary root - b. lateral roots). Secondly, RootIX, an Excel file with dedicated macros that will automatically extract, sort and treat the data, is launched. Tables and graphics describing the data are generated. Root length, elongation rate and additional lateral roots are the main indicators provided among many others. We evaluated the effect of algae extracts on tomato roots growth with RootIX. We highlighted that these compounds negatively affect root growth while promoting generation of lateral roots.Conclusion: Ease of use and settings as well as complete data analyses without any cost are the scaffold of RootIX.

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