A cyst nematode effector binds to diverse plant proteins, increases nematode susceptibility and affects root morphology

Abstract

Cyst nematodes are plant-parasitic roundworms that are of significance in many cropping systems around the world. Cyst nematode infection is facilitated by effector proteins secreted from the nematode into the plant host. The cDNAs of the 25A01-like effector family are novel sequences that were isolated from the oesophageal gland cells of the soybean cyst nematode (Heterodera glycines). To aid functional characterization, we identified an orthologous member of this protein family (Hs25A01) from the closely related sugar beet cyst nematode H. schachtii, which infects Arabidopsis. Constitutive expression of the Hs25A01 CDS in Arabidopsis plants caused a small increase in root length, accompanied by up to a 22% increase in susceptibility to H. schachtii. A plant-expressed RNA interference (RNAi) construct targeting Hs25A01 transcripts in invading nematodes significantly reduced host susceptibility to H. schachtii. These data document that Hs25A01 has physiological functions in planta and a role in cyst nematode parasitism. In vivo and in vitro binding assays confirmed the specific interactions of Hs25A01 with an Arabidopsis F-box-containing protein, a chalcone synthase and the translation initiation factor eIF-2 β subunit (eIF-2bs), making these proteins probable candidates for involvement in the observed changes in plant growth and parasitism. A role of eIF-2bs in the mediation of Hs25A01 virulence function is further supported by the observation that two independent eIF-2bs Arabidopsis knock-out lines were significantly more susceptible to H. schachtii.

An Effector from the Cyst Nematode Heterodera schachtii Derepresses Host rRNA Genes by Altering Histone Acetylation

“…Identification of host plant proteins that physically interact with nematode effectors is a promising approach to elucidate effector function (Hewezi et al, 2008(Hewezi et al, , 2010(Hewezi et al, , 2015Pogorelko et al, 2016). To this end, we performed yeast two-hybrid (Y2H) screens using the 32E03 coding sequence without the secretory signal peptide sequence as bait for prey libraries derived from H. schachtiiinfected Arabidopsis root cDNA (Hewezi et al, 2008).…”

Re‐targeting of a plant defense protease by a cyst nematode effector

“…The resultant pET‐15b recombinant plasmids were subjected to pull‐down assays according to the procedure described previously (Pogorelko et al ., ,b).…”

“…Protein samples were analyzed by immunoblotting with tag‐specific antibodies as described previously (Pogorelko et al ., ,b). Primary anti‐GFP monoclonal antibody (Covance; MMS‐118P) at a dilution of 1:6000 and secondary anti‐mouse IgG (whole molecule) peroxidase antibody (MilliporeSigma, St. Louis, MO, USA; A9044) at a dilution of 1:20 000 were used for the detection of YFP fusion proteins.…”

The plant‐parasitic cyst nematode effector GLAND4 is a DNA‐binding protein

“…The sequences have been subjected to bioinformatic filtering and verification of transcript accumulation in the gland cells to ensure a high likelihood of secretion during parasitism (Noon et al, 2015). The characterization of a subset of these candidate effectors by the identification of effector-plant protein interactions has revealed functions relating to cell wall modification, antioxidant production, hormone signalling, plant defence suppression and host peptide mimicry (Hamamouch et al, 2012;Hewezi et al, 2008Hewezi et al, , 2010Hewezi et al, , 2015Lee et al, 2011;Noon et al, 2016;Patel et al, 2010;Pogorelko et al, 2016;Vanholme et al, 2009;Wang et al, 2005). Effectors in other pathogens, most notably Xanthomonas spp., are known to interact directly with host DNA to modify host gene transcription (de Lange et al, 2013;Li et al, 2013;Nissan et al, 2006;Padavannil et al, 2014;Yang et al, 2000).…”