Two chorismate mutase genes from the root‐knot nematode Meloidogyne incognita

Abstract

SUMMARY Parasitism genes encoding secretory proteins expressed in the oesophageal glands of phytoparasitic nematodes play critical roles in nematode invasion of host plants, establishment of feeding sites and suppression of host defences. Two chorismate mutase (CM) genes potentially having a role in one or more of these processes were identified from a Meloidogyne incognita oesophageal gland-cell subtractive cDNA library. These M. incognita enzymes (designated as MI-CM-1 and MI-CM-2) with amino-terminal signal peptides, were significantly similar to chorismate mutases in M. javanica and bacteria. The complementation of an Escherichia coli CM-deficient mutant by the expression of Mi-cm-1 or Mi-cm-2 confirmed their CM activity. In-situ mRNA hybridization showed that the transcripts of Mi-cm-1 and Mi-cm-2 accumulated specifically in the two subventral oesophageal gland cells of M. incognita. RT-PCR analysis confirmed that their transcript abundances were high in the early parasitic juvenile stages, and low (Mi-cm-1) or undetectable (Mi-cm-2) in later parasitic stages of the nematode. Southern blot analysis revealed that these CM genes were members of a small multigene family in Meloidogyne species. The widespread presence of CMs in the specialized sedentary endoparasitic nematode species suggests that this multifunctional enzyme may be a key factor in modulating plant parasitism.

Identification of Novel Target Genes for Safer and More Specific Control of Root-Knot Nematodes from a Pan-Genome Mining

“…Among these 232 effector-like proteins, we found 42 previously reported RKN effectors, including SXP/RAL-2 like proteins [16], Venom Allergen-like Proteins (VAP) [17], Chorismate mutases [18], Cathepsin L-like protease 1 (MiCpl1) [19] as well as 32 plant cell wall-degrading enzymes, encompassing cellulases, xylanases, pectate lyases and expansin-like proteins [20]. Finding previously known and characterized Meloidogyne effectors among our list of predicted effectors constituted an important validation of our approach.…”

Gall-forming root-knot nematodes hijack key plant cellular functions to induce multinucleate and hypertrophied feeding cells

“…Mj-FAR-1 was shown to promote giant cells and nematode development when expressed in planta (Iberkleid et al, 2013). Similarly, secreted proteins homologous to plant chorismate mutases have been characterized in RKN (Doyle & Lambert, 2003;Huang et al, 2005). Chorismate mutase overexpression in planta altered root growth and it has been suggested that this effector affects the auxin pool within host cells.…”

Functional roles of effectors of plant-parasitic nematodes

“…Several different plant nematode groups including cyst nematodes, RKNs and migratory endoparasites such as P. coffeae (Doyle and Lambert, 2003;Haegeman et al, 2011a;Huang et al, 2005b;Jones et al, 2003;Lambert et al, 1999;Long et al, 2006;Lu et al, 2008;Vanholme et al, 2009b) produce chorismate mutases (CM) as part of their effector complement. Chorismate mutase is a key regulatory enzyme in the shikimate pathway in plants and bacteria and the fact that no other enzymes from this pathway are present in PPNs strongly indicates a role in the host plant.…”