Glycine max Homologs of DOESN'T MAKE INFECTIONS 1, 2, and 3 Function to Impair Heterodera glycines Parasitism While Also Regulating Mitogen Activated Protein Kinase Expression

Abstract

Glycine maxroot cells developing into syncytia through the parasitic activities of the pathogenic nematodeHeterodera glycinesunderwent isolation by laser microdissection (LM). Microarray analyses have identified the expression of aG. max DOESN'T MAKE INFECTIONS3(DMI3) homolog in syncytia undergoing parasitism but during a defense response.DMI3encodes part of the common symbiosis pathway (CSP) involvingDMI1, DMI2, and other CSP genes. The identifiedDMIgene expression, and symbiosis role, suggests the possible existence of commonalities between symbiosis and defense.G. maxhas 3DMI1, 12DMI2, and 2DMI3paralogs. LM-assisted gene expression experiments of isolated syncytia under further examination here showG. max DMI1-3, DMI2-7, andDMI3-2expression occurring during the defense response in theH. glycines-resistant genotypesG.max[Peking/PI548402]andG.max[PI88788]indicating a broad and consistent level of expression of the genes. Transgenic overexpression (OE) ofG. max DMI1-3, DMI2-7, andDMI3-2impairsH. glycinesparasitism. RNA interference (RNAi) ofG. max DMI1-3, DMI2-7, andDMI3-2increasesH. glycinesparasitism. The combined opposite outcomes reveal a defense function for these genes. Prior functional transgenic analyses of the 32-memberG. max mitogen activated protein kinase(MAPK) gene family has determined that 9 of them act in the defense response toH. glycinesparasitism, referred to as defenseMAPKs. RNA-seq analyses of root RNA isolated from the 9G. maxdefenseMAPKs undergoing OE or RNAi reveal they alter the relative transcript abundances (RTAs) of specificDMI1, DMI2, andDMI3paralogs. In contrast, transgenically-manipulatedDMI1-3, DMI2-7, andDMI3-2expression influencesMAPK3-1andMAPK3-2RTAs under certain circumstances. The results showG. maxhomologs of the CSP, and defense pathway are linked, apparently involving co-regulated gene expression.