Parasitism by Cuscuta pentagona sequentially induces JA and SA defence pathways in tomato

Abstract

While plant responses to herbivores and pathogens are well characterized, responses to attack by other plants remain largely unexplored. We measured phytohormones and C18 fatty acids in tomato attacked by the parasitic plant Cuscuta pentagona, and used transgenic and mutant plants to explore the roles of the defence-related phytohormones salicylic acid (SA) and jasmonic acid (JA). Parasite attachment to 10-day-old tomato plants elicited few biochemical changes, but a second attachment 10 d later elicited a 60-fold increase in JA, a 30-fold increase in SA and a hypersensitive-like response (HLR). Host age also influenced the response: neither Cuscuta seedlings nor established vines elicited a HLR in 10-day-old hosts, but both did in 20-day-old hosts. Parasites grew larger on hosts deficient in SA (NahG) or insensitive to JA [ jasmonic acidinsensitive1 ( jai1) ], suggesting that both phytohormones mediate effective defences. Moreover, amounts of JA peaked 12 h before SA, indicating that defences may be coordinated via sequential induction of these hormones. Parasitism also induced increases in free linolenic and linoleic acids and abscisic acid. These findings provide the first documentation of plant hormonal signalling induced by a parasitic plant and show that tomato responses to C. pentagona display characteristics similar to both herbivoreand pathogen-induced responses.

De Novo Assembly and Characterization of the Transcriptome of the Parasitic Weed Dodder Identifies Genes Associated with Plant Parasitism

“…Thus, it can be hypothesized that parasitic plants recruit defense-related genes for host recognition. Considering that a host may demonstrate active defense responses to dodder attack (Runyon et al, 2010), it also appears that the parasite is under biotic stress and, hence, may recruit its own defense mechanism to overcome the counterattack.…”

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

“…The root parasite Orobanchae ramose induced JA-dependent genes but not SA-dependent genes in Arabidopsis (Dos Santos et al 2003). As for Cuscuta, only one previous study by Runyon et al (2010) suggested that both JA and SA responded after Cuscuta pentagona parasitization of tomatoes (Solaum lycopersicum), and the JA peak was prior to SA. In our Cuscuta-Momordica interaction, JA was not changed but SA was increased in Momordica.…”

“…Previously, Runyon et al (2010) found hypersensitive-like response (HLR) in tomatoes (Solaum lycopersicum), which was provoked by Cuscuta pentagona. HLR was observed only in 20-day-old tomatoes (both at hypocotyls and petiole).…”

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

“…Parasitic plants make their living by extracting resources from other plants and, therefore, share many of the same ecological challenges faced by other plantfeeding organisms, including the need to acquire appropriate hosts and overcome host defenses (Runyon et al, 2006(Runyon et al, , 2008(Runyon et al, , 2010Mescher et al, 2009;Smith et al, 2009). In the case of arthropod herbivores, many species are able not only to overcome the chemical defenses of their hosts but also to sequester plant toxins for use against their own natural enemies (Opitz and Mueller, 2009).…”