Only a small subset of the SPRY domain gene family in Globodera pallida is likely to encode effectors, two of which suppress host defences induced by the potato resistance gene Gpa2

Abstract

Analysis of the genome sequence of the potato cyst nematode, Globodera pallida, has shown that a substantial gene family (approximately 300 sequences) of proteins containing a SPRY domain is present in this species. This is a huge expansion of the gene family as compared to other organisms, including other plant-parasitic nematodes. Some SPRY domain proteins from G. pallida and G. rostochiensis have signal peptides for secretion and are deployed as effectors. One of these SPRYSEC proteins has been shown to suppress host defence responses. We describe further analysis of this gene family in G. pallida. We show that only a minority (10%) of the SPRY domain proteins in this species have a predicted signal peptide for secretion and that the presence of a signal peptide is strongly correlated with the corresponding gene being expressed at the early stages of parasitism. The data suggest that while the gene family is greatly expanded, only a minority of SPRY domain proteins in G. pallida are SPRYSEC candidate effectors. We show that several new SPRYSECs from G. pallida are expressed in the dorsal gland cell and demonstrate that some, but not all, of the SPRYSECs can suppress the hypersensitive response induced by co-expression of the resistance gene Gpa2 and its cognate avirulence factor RBP-1 in Nicotiana benthamiana.

The genome of the soybean cyst nematode (Heterodera glycines) reveals complex patterns of duplications involved in the evolution of parasitism genes

“…While the remaining 215 effector-like loci may contain non-effectors, they were retained for downstream evolutionary analyses because they may represent genes with non-canonical secretion signals, "progenitor" housekeeping genes that gave rise to effectors (e.g. GS-like effectors [19], SPRY-SECs [21], etc. ), or an effector graveyard.…”

SIZ1 is a nuclear host target of the nematode effector GpRbp1 from Globodera pallida that acts as a negative regulator of basal plant defense to cyst nematodes

“…The" nematode" effector" GpRbp,1" belongs" to" the" highly" expanded" family" of" SPRYSEC" 129" proteins"of"the"potato"cyst"nematodes"Globodera#pallida"and"G.#rostochiensis" (Diaz,Granados# 130" et# al.," 2016;" Jones# et# al.," 2009;" Mei# et# al.," 2015;" Rehman# et# al.," 2009). " SPRYSEC" effectors" 131" contain" an" N,terminal" signal" peptide" for" secretion" and" a" C,terminal" SPRY" domain."…”

Genome scans on experimentally evolved populations reveal candidate regions for adaptation to plant resistance in the potato cyst nematode Globodera pallida

“…The fact that a considerable part of the outlier loci are found near genes coding for a SPRY domain‐containing protein or even in or at the vicinity of SPRYSECs cannot be only explained by the huge size of this family gene or the prevalence of the SPRY domain in the G. pallida genome. In fact, 299 SPRY domain‐containing proteins are present in the G. pallida genome (which can be moreover cluster into islands), that is, 1 for 334 kb, and 30 of them are SPRYSECs, that is, 1 SPRYSEC for 3.33 Mb (Eves‐van den Akker et al., ; Mei et al., ). When looking at the genic environment of outlier loci, we explored a total of 2 Mb of the genome and we identified 15 SPRY domain‐containing proteins, that is, 1 for 133 kb, and 3 SPRYSECs, that is, 1 for 660 kb.…”