Parasitic Plants: An Overview of Mechanisms by Which Plants Perceive and Respond to Parasites

Abstract

In contrast to most autotrophic plants, which produce carbohydrates from carbon dioxide using photosynthesis, parasitic plants obtain water and nutrients by parasitizing host plants. Many important crop plants are infested by these heterotrophic plants, leading to severe agricultural loss and reduced food security. Understanding how host plants perceive and resist parasitic plants provides insight into underlying defense mechanisms and the potential for agricultural applications. In this review, we offer a comprehensive overview of the current understanding of host perception of parasitic plants and the pre-attachment and post-attachment defense responses mounted by the host. Since most current research overlooks the role of organ specificity in resistance responses, we also summarize the current understanding and cases of cross-organ parasitism, which indicates nonconventional haustorial connections on other host organs, for example, when stem parasitic plants form haustoria on their host roots. Understanding how different tissue types respond to parasitic plants could provide the potential for developing a universal resistance mechanism in crops against both root and stem parasitic plants. Expected final online publication date for the Annual Review of Plant Biology, Volume 73 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Cuscuta species: Model organisms for haustorium development in stem holoparasitic plants

“…Besides serving as a sound system for studying the distinctive mechanisms involved in haustorium initiation, Cuscuta species also perform some unique parasitizing behaviours that are currently underinvestigated, including hyperparasitism ( Wilson and Calvin, 2017 ), autoparasitism ( Krasylenko et al., 2021 ), and cross-organ parasitism ( Jhu and Sinha, 2022 ). These unique parasitizing behaviours among multiple parasitic plants have been previously reviewed ( Krasylenko et al., 2021 ; Jhu and Sinha, 2022 ). Therefore, here, we focus on providing clear definitions with concise discussion and then propose hypotheses to understand why Cuscuta species evolved these unique parasitizing behaviours.…”

“…Cross-organ parasitism refers to the phenomenon of a parasitic plant forming nonconventional haustorial attachments with other host organs ( Jhu and Sinha, 2022 ). For example, C. campestris is known as a parasitic stem plant but has been reported to be able to form haustoria on tomato seedling roots ( Jhu and Sinha, 2022 ). The reason why Cuscuta species evolved to have the ability to parasitize different organs of their host is still a mystery.…”

“…Therefore, a better understanding of the mechanisms involved in Cuscuta haustorium development is required to build more effective control strategies to stop the agricultural damages brought on by Cuscuta . During the past decade, progress has been made in understanding the interaction between Cuscuta species and their hosts, especially on the mechanism involved in resistance responses against Cuscuta species ( Kaiser et al., 2015 ; Jhu and Sinha, 2022 ), and the signal exchange and horizontal gene transfer between Cuscuta plants and their hosts ( Kim and Westwood, 2015 ; Wu, 2018 ; Yang et al., 2019 ; Lin et al., 2022 ). These aspects have been reviewed recently ( Kaiser et al., 2015 ; Kim and Westwood, 2015 ; Wu, 2018 ; Jhu and Sinha, 2022 ).…”

“…During the past decade, progress has been made in understanding the interaction between Cuscuta species and their hosts, especially on the mechanism involved in resistance responses against Cuscuta species ( Kaiser et al., 2015 ; Jhu and Sinha, 2022 ), and the signal exchange and horizontal gene transfer between Cuscuta plants and their hosts ( Kim and Westwood, 2015 ; Wu, 2018 ; Yang et al., 2019 ; Lin et al., 2022 ). These aspects have been reviewed recently ( Kaiser et al., 2015 ; Kim and Westwood, 2015 ; Wu, 2018 ; Jhu and Sinha, 2022 ). On the other hand, although review articles cover some specific aspects of Cuscuta haustorium development and parasitism behaviours ( Yoshida et al., 2016 ; Shimizu and Aoki, 2019 ), several recent discoveries in the field have not been systematically reviewed yet.…”

Protein Profiling of Psittacanthus calyculatus during Mesquite Infection

“…Diverse parasitic hormones have been anticipated in the site of infection from gene expression analysis related to accumulation of auxins in the early stages of the haustorium development [ 36 , 37 , 38 , 39 , 40 ]. Nevertheless, successful infection of P. calyculatus in a host tree is dependent on the establishment mechanisms in phenological stages such as germination and growth of seedlings, as well as metabolic signatures in haustorium development, enzymes involved in bark layer degradation and xylem connection, and molecular and genetic factors that inhibit the host immune system [ 34 , 41 , 42 , 43 , 44 , 45 , 46 ]. Therefore, molecular analyses on the development of the haustorium are necessary, involving scanning biomolecules such as phytohormones, proteins, and enzymes involved in haustorium development and thus in the establishment on the host.…”