Alterations in the primary metabolite profiles of field dodder (Cuscuta campestris) and its associated hosts cutleaf evening primrose (Oenothera laciniata) and swine cress (Coronopus didymus) in the fields of North-West India

Cutleaf evening primrose (Oenothera laciniata Hill.) and swine cress (Coronopus didymus (L.) Sm.) are the two weeds which were found to be infested by a stem holoparasitic plant, field dodder (Cuscuta campestris Yunck.) in the fields of Punjab Agricultural University, Ludhiana, Punjab, during 2023-24. Although, detailed records of host-parasite associations of Cuscuta spp. are present in a large number of field crops predominantly belonging to families Solanaceae, Poaceae, Leguminosae and Brassicaceae; this is the first report to our knowledge of parasitic associations of C. campestris to two new weeds as hosts - O. laciniata and C. didymus belonging to the families Onagraceae and Brassicaceae, respectively in the fields under continuous rice-wheat rotation since more than twenty years. Parasitic plants are finding new hosts owing to increasing concerns of habitat suitability and host variability amidst rising trends of global climate change for agriculturalists. Biochemical analysis documented nutrient acquisition by field dodder from weed hosts, demonstrating the different host parasite assemblages as cause for variation in the primary metabolites’ profiling in the hosts as well as the parasite. Evidently, the stem and leaves of O. laciniata and C. didymus were used by this noxious parasitic weed as a means for reaching the fruits of its host for maximum nutrient acquisition so as to complete its life cycle and expanding its seed bank in a field where its few seeds may have accidentally arrived from an unknown source.