A host‐free transcriptome for haustoriogenesis in Cuscuta campestris: Signature gene expression identifies markers of successive development stages

The development of the infection organ of the parasitic angiosperm genus Cuscuta is a dynamic process that is normally obscured from view as it happens endophytically in its host. We artificially induced haustoriogenesis in Cuscuta campestris by far‐red light to define specific morphologically different stages and analyze their transcriptional patterns. This information enabled us to extract sets of high‐confidence housekeeping and marker genes for the different stages, validated in a natural infection setting on a compatible host. This study provides a framework for more reproducible investigations of haustoriogenesis and the processes governing host–parasite interactions in shoot parasites, with C. campestris as a model species.