The Angiosperm Stem Hemiparasitic Genus Cassytha (Lauraceae) and Its Host Interactions: A Review

Abstract

Cassytha, also known as laurel dodder or love vine, is a stem hemiparasite of the Lauraceae family. It has long been used for medicinal purposes in many countries and has increasingly influenced agricultural and natural ecosystems by its effects on a wide range of host species. Previous studies have focused on the taxonomy and evolutionary position of different Cassytha, with the pan-tropical species Cassytha filiformis being the most widely studied. However, Cassytha–host interactions have never been reviewed, which is an essential issue related to the understanding of mechanisms underlying plant hemiparasitic and the assessment of benefits and damage caused by aerial parasitic plants. This review explores the parasitic habits, worldwide distribution, and host range of Cassytha, and examines its impacts on the biology of host plants and the overall influence of environmental changes on Cassytha–host associations. We also comment on areas of future research directions that require to better understanding Cassytha–host interactions. It appeared that some traits, such as flowering phenology, facilitated Cassytha’s widespread distribution and successful parasitism and that Cassytha preferred woody species rather than herbaceous species as a host, and preferred species from certain families as hosts, such as Fabaceae and Myrtaceae. Cassytha often decreased biomass and impacted the physiology of host species and global environmental changes seemed to intensify the negative impacts of Cassytha on their hosts. Cassytha was not only a noxious weed, but can also function as a biocontrol agent to mitigate alien plant invasion.

The recent expansion of the invasive hemiparasitic plant Cassytha filiformis and the reciprocal effect with its main hosts

“…Cassytha lliformis (Lauraceae) is originally from Asia and has a pantropical distribution encompassing the Americas, Indomalaya, Australasia, Polynesia, and tropical Africa (Zhang et al 2022). However, it is considered a potentially invasive alien species on the northern coast of the Peninsula of Yucatán (Parra-Tabla et al 2018).…”

“…Like other species within the genus, the effects of this species on host plants include reduced growth, biomass, reproduction, and, under severe infestation, host death (Nelson 2008;Prider et al 2009). In contrast, there is much less evidence about the sexual reproductive success of C. lliformis growing on different hosts (Zhang et al 2022). C. lliformis parasitizes shrubs and trees and attacks a wide range of hosts (e.g.,…”

“…In this case, it is expected a preference for long-lived hosts. In addition, host selection by Cassytha seems to be related to the morphological characteristics of the host plant since better performance occurs when growing on shorter trees and shrubs(Zhang et al 2022). Speci cally, C. liformis prefers low and branched woody host plants(Werth et al 1979).…”

Review on Ethnobotany and phytochemistry of Cassytha filiformis

“…The host plant will eventually be suppressed and sometimes killed. With time, the haustoria will flower and seed -the seed being spread by the wind, by water or by birds [2,4,5].…”

“…This haustorium will penetrate the host plant epidermis, entering into the xylem and phloem to absorb water and nutrition. The seeds can be spread between continents by ocean currents, as well as by birds and wind [2].…”