Transfer of phloem-mobile substances from the host plants to the holoparasite Cuscuta sp.

Abstract

During the development of the haustorium, searching hyphae of the parasite and the host parenchyma cells are connected by plasmodesmata. Using transgenic tobacco plants expressing a GFP-labelled movement protein of the tobacco mosaic virus, it was demonstrated that the interspecific plasmodesmata are open. The transfer of substances in the phloem from host to the parasite is not selective. After simultaneous application of (3)H-sucrose and (14)C-labelled phloem-mobile amino acids, phytohormones, and xenobiotica to the host, corresponding percentages of the translocated compounds are found in the parasite. An open continuity between the host phloem and the Cuscuta phloem via the haustorium was demonstrated in CLSM pictures after application of the phloem-mobile fluorescent probes, carboxyfluorescein (CF) and hydroxypyrene trisulphonic acid (HPTS), to the host. Using a Cuscuta bridge (14)C-sucrose and the virus PVY(N) were transferred from one host plant to the another. The results of translocation experiments with labelled compounds, phloem-mobile dyes and the virus should be considered as unequivocal evidence for a symplastic transfer of phloem solutes between Cuscuta species and their compatible hosts.

Glucosinolates from Host Plants Influence Growth of the Parasitic Plant Cuscuta gronovii and Its Susceptibility to Aphid Feeding

“…The phytohormone auxin is readily transferred from hosts to dodder parasites (Birschwilks et al, 2006) and potentially could impact dodder growth and development. As in autotrophic plants, auxin mediates developmental processes in dodder such as apical tip dominance (Maheshwari and Sreekrishna, 1982).…”

“…Dodder species utilize several brassicaceous plants as hosts in nature (Gaertner, 1950) and readily attach to Arabidopsis inflorescences (Birschwilks et al, 2007). These parasites link directly to host xylem and phloem (via penetrative organs called haustoria) and extract diverse solutes, including amino acids, sugars, hormones, proteins, mRNA, and various secondary metabolites (Rothe et al, 1999;Birschwilks et al, 2006Birschwilks et al, , 2007LeBlanc et al, 2013). It was not previously known whether dodders (or other parasitic plants) are capable of taking up host-derived glucosinolates, the major class of defense compounds produced by Arabidopsis and related plants in the order Cappareles.…”

Interspecific RNA Interference of SHOOT MERISTEMLESS-Like Disrupts Cuscuta pentagona Plant Parasitism

“…At points of contact with the host, the coiled dodder stem produces haustoria that penetrate host tissues and form vascular connections (Kuijt, 1983;Vaughn, 2003). Haustoria produce long, unicellular searching hyphae that make many plasmodesmata at the contact point with host parenchyma (Vaughn, 2003;Birschwilks et al, 2006). Eventually, phloem-phloem and xylem-xylem connections formed between dodder and the host are used to transfer water and assimilates to the parasite (Jeschke et al, 1994;Vaughn, 2003;Birschwilks et al, 2006).…”

Morphological and plant hormonal changes during parasitization by Cuscuta japonica on Momordica charantia

“…Some previous studies on parasitic plant interactions have dealt with carbon and nitrogen flows (Hibberd & Jeschke 2001), and the translocation of chemical compounds (including metabolites, small proteins, and mRNA) (Birschwilks et al 2006(Birschwilks et al , 2007LeBlanc et al 2012). While, others focused on defensive responses from host plants to parasitic plants, i.e.…”