Genetic and agronomic approaches to control Orobanche and Phelipanche spp. parasitic weeds in vegetables and legumes

Broomrapes (Orobanche and Phelipanche spp.) rely on the presence of a host plant for nourishment. Based on the release of specific molecules by the crop plant, their seeds germinate and eventually establish a vascular connection with host roots through a haustorium. Therefore, they deprive their hosts of water and nutrients, posing a severe threat to vegetable and legume crops worldwide. Due to their growth behaviour, amount and longevity of seeds released, and, generally, a large variety of hosts, the control of parasitic plants is rather difficult. In this review, we give an update about agronomic and genetic approaches controlling host-parasite interactions. Management of broomrapes in vegetables and legumes relies on different approaches: trap and catch crops; suicidal germination by strigolactones (SLs), analogues and mimics; SL degradation; biological and chemical control; other control methods. Further, the production of resistant cultivars is highly desirable. Some natural sources of resistance have been identified in landraces and wild relatives of vegetable and legume crops. Additional variability has been discovered by artificial mutagenesis, but it has been poorly exploited for breeding commercial cultivars. Recent genomic knowledge in parasitic and host species opens new perspectives for the comprehension of molecular bases of interaction and applied breeding, using molecular assisted breeding and biotechnological approaches aimed to modify genes controlling the various stages of parasitization. Anyway, the combination of different genetic resistance mechanisms with agronomical management practices is mandatory to develop a durable containment strategy.