Mycorrhiza Mutants of Lotus japonicus Define Genetically Independent Steps During Symbiotic Infection

Abstract

Four nodulation mutants of Lotus japonicus affected in three different genetic loci blocked infection by Glomus intraradices within rhizodermal cells where abnormal deformations of hyphae occurred. Rare successful infections led to the formation of arbuscules. The affected plant genes are therefore essential during the early infection process, but are dispensable for later developmental stages.

Dating in the dark: how roots respond to fungal signals to establish arbuscular mycorrhizal symbiosis

“…These receptors are membrane kinases that contain LysM motifs in their extracellular domains [ 20, 21 and 22]. Mutant plants defective in these receptors are still capable of mycorrhiza formation [ 23] The scheme illustrates the signaling transduction pathway in Rhizobial and mycorrhizal symbiosis. While Myc-LCOs are expected to travel along the same pathway required for nodule formation, the so-called common symbiosis (SYM) pathway, additional routes for additional AM signals are expected.…”

The Sym35 Gene Required for Root Nodule Development in Pea Is an Ortholog of Nin from Lotus japonicus

“…Interestingly, some of the non-nodulating mutants were also un-able to interact with mycorrhizal fungi, demonstrating that a set of "common genes" is required for initiating both bacterial symbiosis and endosymbiosis with vesicular arbuscular mycorrhizal fungi (Duc et al, 1989;Wegel et al, 1998;Bonfante et al, 2000;Stougaard, 2001). One of the legume plants traditionally used for gene mapping and investigations of the genetic basis of plant-microbe interactions is pea.…”

Peace Talks and Trade Deals. Keys to Long-Term Harmony in Legume-Microbe Symbioses

“…1). Mutations in all these genes fail to allow entry of the fungus into the cortex (Sagan et al, 1995;Wegel et al, 1998). This implicates the NORK/ SYMRK/DMI2/SYM19 Leu-rich repeat receptor kinase, the DMI1 channel protein, and the DMI3 CCaMK in early mycorrhizal signaling (Endre et al, 2002;Stracke et al, 2002;Ane et al, 2004;Levy et al, 2004;Mitra et al, 2004a).…”