Abstract:Summary
Cowpea (Vigna unguiculata) cultivar B301 is resistant to races SG4 and SG3 of the root parasitic weed Striga gesnerioides, developing a hypersensitive response (HR) at the site of parasite attachment. By contrast, race SG4z overcomes B301 resistance and successfully parasitises the plant.
Comparative transcriptomics and in silico analysis identified a small secreted effector protein dubbed Suppressor of Host Resistance 4z (SHR4z) in the SG4z haustorium that upon transfer to the host roots causes a lo… Show more
“…However, in a few cases the host–parasite interaction is characterized by a host HR, which is a central feature of gene‐for‐gene plant disease resistance resulting in race‐specific resistance. In this respect, the work of Su et al complements previous studies that identified and characterized resistances in cowpea infected with Striga gesnerioides. Botanga & Timko (2005) also demonstrated that at least seven distinct races of Striga gesnerioides parasite cowpea in West Africa.…”
supporting
confidence: 55%
“…If this concept applies to many pathogens, including viruses, bacteria, fungi, and nematodes, what about parasitic plants? The elegant work by Su et al ., published in this issue of New Phytologist (2020; pp. 890–907) answers this question unequivocally by demonstrating, for the first time, that Striga gesnerioides , a root parasitic weed, produces, as any nonplant phytopathogens, a protein effector that mimics the components of its host, the cowpea, to gain evolutionary advantages and break down its resistance.‘These findings lay the groundwork for a better understanding of how new races of parasitic plants might emerge by deploying a fine and effective strategy to break down host resistance.’…”
mentioning
confidence: 99%
“…In their study, Su et al demonstrated for the first time that SG4z effectively produces a protein effector Suppressor of Host Resistance 4z (SHR4z) in its haustorium that, once transferred to the host, interferes with the signaling pathway normally triggered during a resistant interaction. Indeed, the parasitic SHR4z shows similarities with a SERK‐type protein co‐receptor from the host, which is a known component of the plant immune response leading to HR.…”
“…However, in a few cases the host–parasite interaction is characterized by a host HR, which is a central feature of gene‐for‐gene plant disease resistance resulting in race‐specific resistance. In this respect, the work of Su et al complements previous studies that identified and characterized resistances in cowpea infected with Striga gesnerioides. Botanga & Timko (2005) also demonstrated that at least seven distinct races of Striga gesnerioides parasite cowpea in West Africa.…”
supporting
confidence: 55%
“…If this concept applies to many pathogens, including viruses, bacteria, fungi, and nematodes, what about parasitic plants? The elegant work by Su et al ., published in this issue of New Phytologist (2020; pp. 890–907) answers this question unequivocally by demonstrating, for the first time, that Striga gesnerioides , a root parasitic weed, produces, as any nonplant phytopathogens, a protein effector that mimics the components of its host, the cowpea, to gain evolutionary advantages and break down its resistance.‘These findings lay the groundwork for a better understanding of how new races of parasitic plants might emerge by deploying a fine and effective strategy to break down host resistance.’…”
mentioning
confidence: 99%
“…In their study, Su et al demonstrated for the first time that SG4z effectively produces a protein effector Suppressor of Host Resistance 4z (SHR4z) in its haustorium that, once transferred to the host, interferes with the signaling pathway normally triggered during a resistant interaction. Indeed, the parasitic SHR4z shows similarities with a SERK‐type protein co‐receptor from the host, which is a known component of the plant immune response leading to HR.…”
“…The deployment of secreted effectors to block host resistance responses is observed in multiple host-pathogen interactions including pathogenic microbes, fungi, and nematodes [ 145 , 146 , 147 ]. Recently, Su et al [ 148 ] used transcriptomic profiling and transgenic expression analysis to identify a novel secreted effector protein from S. gesnerioides termed SHR4z, which blocks host plant immunity in the multi-race resistance cowpea B301. SHR4z suppresses the hypersensitive response (HR) triggered by S. gesnerioides race SG4 by interfering with signal transduction pathway leading to HR activation upon parasite attack.…”
Parasitic plants rely on neighboring host plants to complete their life cycle, forming vascular connections through which they withdraw needed nutritive resources. In natural ecosystems, parasitic plants form one component of the plant community and parasitism contributes to overall community balance. In contrast, when parasitic plants become established in low biodiversified agroecosystems, their persistence causes tremendous yield losses rendering agricultural lands uncultivable. The control of parasitic weeds is challenging because there are few sources of crop resistance and it is difficult to apply controlling methods selective enough to kill the weeds without damaging the crop to which they are physically and biochemically attached. The management of parasitic weeds is also hindered by their high fecundity, dispersal efficiency, persistent seedbank, and rapid responses to changes in agricultural practices, which allow them to adapt to new hosts and manifest increased aggressiveness against new resistant cultivars. New understanding of the physiological and molecular mechanisms behind the processes of germination and haustorium development, and behind the crop resistant response, in addition to the discovery of new targets for herbicides and bioherbicides will guide researchers on the design of modern agricultural strategies for more effective, durable, and health compatible parasitic weed control.
“…In contrast, an effector from an S. gesnerioides race that is able to suppress, but not activate, host defense responses in cowpea B301, has been identified (Su et al, 2020). The effector, designated…”
Summary
Parasitic plants in the family Orobanchaceae, such as Striga, Orobanche and Phelipanche, often cause significant damage to agricultural crops. The Orobanchaceae family comprises more than 2000 species in about 100 genera, providing an excellent system for studying the molecular basis of parasitism and its evolution. Notably, the establishment of model Orobanchaceae parasites, such as Triphysaria versicolor and Phtheirospermum japonicum, that can infect the model host Arabidopsis, has greatly facilitated transgenic analyses of genes important for parasitism. In addition, recent genomic and transcriptomic analyses of several Orobanchaceae parasites have revealed fascinating molecular insights into the evolution of parasitism and strategies for adaptation in this family. This review highlights recent progress in understanding how Orobanchaceae parasites attack their hosts and how the hosts mount a defense against the threats.
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