Epidermal cells of a symbiosis-defective mutant of Lotus japonicus show altered cytoskeleton organisation in the presence of a mycorrhizal fungus

PROTOPLASMA ◽  
2002 ◽  
Vol 219 (1-2) ◽  
pp. 43-50 ◽  
Author(s):  
A. Genre ◽  
P. Bonfante
Keyword(s):  
Mycorrhizal Fungus ◽  
Lotus Japonicus ◽  
Epidermal Cells ◽  
Defective Mutant

scholarly journals Symbiotic responses of Lotus japonicus to two isogenic lines of a mycorrhizal fungus differing in the presence/absence of an endobacterium

2021 ◽  
Author(s):  
Francesco Venice ◽  
Matteo Chialva ◽  
Guido Domingo ◽  
Mara Novero ◽  
Andrea Carpentieri ◽  
...  
Keyword(s):  
Mycorrhizal Fungus ◽  
Lotus Japonicus ◽  
Isogenic Lines

scholarly journals Epidermal LysM receptor ensures robust symbiotic signalling in Lotus japonicus

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Eiichi Murakami ◽  
Jeryl Cheng ◽  
Kira Gysel ◽  
Zoltan Bozsoki ◽  
Yasuyuki Kawaharada ◽  
...  
Keyword(s):  
Root System ◽  
Lotus Japonicus ◽  
Transcriptional Response ◽  
Epidermal Cells ◽  
Nitrogen Fixing ◽  
Nod Factors ◽  
Nod Factor ◽  
Large Families ◽  
Calcium Spiking ◽  
Spatio Temporal

Recognition of Nod factors by LysM receptors is crucial for nitrogen-fixing symbiosis in most legumes. The large families of LysM receptors in legumes suggest concerted functions, yet only NFR1 and NFR5 and their closest homologs are known to be required. Here we show that an epidermal LysM receptor (NFRe), ensures robust signalling in L. japonicus. Mutants of Nfre react to Nod factors with increased calcium spiking interval, reduced transcriptional response and fewer nodules in the presence of rhizobia. NFRe has an active kinase capable of phosphorylating NFR5, which in turn, controls NFRe downstream signalling. Our findings provide evidence for a more complex Nod factor signalling mechanism than previously anticipated. The spatio-temporal interplay between Nfre and Nfr1, and their divergent signalling through distinct kinases suggests the presence of an NFRe-mediated idling state keeping the epidermal cells of the expanding root system attuned to rhizobia.

scholarly journals The Ethylene Responsive Factor Required for Nodulation 1 (ERN1) Transcription Factor Is Required for Infection-Thread Formation in Lotus japonicus

2017 ◽  
Vol 30 (3) ◽  
pp. 194-204 ◽  
Author(s):  
Yasuyuki Kawaharada ◽  
Euan K. James ◽  
Simon Kelly ◽  
Niels Sandal ◽  
Jens Stougaard
Keyword(s):  
Transcription Factor ◽  
Root Nodule ◽  
Lotus Japonicus ◽  
Epidermal Cells ◽  
Infection Thread ◽  
Nod Factor ◽  
Infection Threads ◽  
Thread Formation ◽  
Ethylene Responsive Factor ◽  
Infection Thread Formation

Several hundred genes are transcriptionally regulated during infection-thread formation and development of nitrogen-fixing root nodules. We have characterized a set of Lotus japonicus mutants impaired in root-nodule formation and found that the causative gene, Ern1, encodes a protein with a characteristic APETALA2/Ethylene Responsive Factor (AP2/ERF) transcription-factor domain. Phenotypic characterization of four ern1 alleles shows that infection pockets are formed but root-hair infection threads are absent. Formation of root-nodule primordia is delayed and no normal transcellular infection threads are found in the infected nodules. Corroborating the role of ERN1 (ERF Required for Nodulation1) in nodule organogenesis, spontaneous nodulation induced by an autoactive CCaMK and cytokinin–induced nodule primordia were not observed in ern1 mutants. Expression of Ern1 is induced in the susceptible zone by Nod factor treatment or rhizobial inoculation. At the cellular level, the pErn1:GUS reporter is highly expressed in root epidermal cells of the susceptible zone and in the cortical cells that form nodule primordia. The genetic regulation of this cellular expression pattern was further investigated in symbiotic mutants. Nod factor induction of Ern1 in epidermal cells was found to depend on Nfr1, Cyclops, and Nsp2 but was independent of Nin and Nf-ya1. These results suggest that ERN1 functions as a transcriptional regulator involved in the formation of infection threads and development of nodule primordia and may coordinate these two processes.

Ultrastructure of Mycorrhizas of Dracophyllum secundum R. Br. (Ericales:Epacridaceae)

1989 ◽  
Vol 16 (1) ◽  
pp. 147 ◽  
Author(s):  
WK Allen ◽  
WG Allaway ◽  
GC Cox ◽  
PG Valder
Keyword(s):  
Structural Integrity ◽  
Fungal Endophytes ◽  
Mycorrhizal Fungus ◽  
Fungal Endophyte ◽  
Epidermal Cells ◽  
Root Cells ◽  
Hair Roots ◽  
Ericoid Mycorrhizas ◽  
Hyphal Coils ◽  
Plant Plasma Membrane

Dracophyllum secundum R. Br. (Epacridaceae) often possessed ericoid mycorrhizas; fungal endophytes formed coils within cells of the epidermis of hair-roots. The plant plasma membrane extended around the hyphae. In some epidermal cells of hair-roots, both plant and fungal cells retained their structural integrity, both partners showing mitochondrial, vacuolar and lipid droplet profiles, and with much of the plant cytoplasm associated with the hyphal coils. In other epidermal cells of hair-roots, fungal coils were present but cytoplasmic features of both symbionts appeared to have broken down. Some epidermal cells showed no evidence of fungal infection. These three arrangements could occur in root-cells of the same age, and are interpreted as resulting from different stages in the development and degeneration of the infection by the mycorrhizal fungus. Two structural types of fungal endophyte here found in ericoid mycorrhizas in D. secundum: one with simple septa, Woronin bodies and two-layered walls (presumed to be an Ascomycete), and another with dolipore septa with imperforate parenthesomes (presumed to be a Basidiomycete). The possibilities that the mycorrhizas may be seasonal, and that mycorrhizal status varies from place to place, are discussed.

scholarly journals The Lotus japonicus LjSym4 Gene Is Required for the Successful Symbiotic Infection of Root Epidermal Cells

2000 ◽  
Vol 13 (10) ◽  
pp. 1109-1120 ◽  
Author(s):  
Paola Bonfante ◽  
Andrea Genre ◽  
Antonella Faccio ◽  
Isabella Martini ◽  
Leif Schauser ◽  
...  
Keyword(s):  
Root Hair ◽  
Glomus Intraradices ◽  
Lotus Japonicus ◽  
Am Fungi ◽  
Epidermal Cells ◽  
Parental Line ◽  
Entry Site ◽  
Symbiotic Interaction ◽  
Successful Infection ◽  
Infection Threads

The role of the Lotus japonicus LjSym4 gene during the symbiotic interaction with Mesorhizobium loti and arbuscular mycorrhizal (AM) fungi was analyzed with two mutant alleles conferring phenotypes of different strength. Ljsym4-1 and Ljsym4-2 mutants do not form nodules with M. loti.Normal root hair curling and infection threads are not observed, while a nodC-dependent deformation of root hair tips indicates that nodulation factors are still perceived by Ljsym4 mutants. Fungal infection attempts on the mutants generally abort within the epidermis, but Ljsym4-1 mutants allow rare, successful, infection events, leading to delayed arbuscule formation. On roots of mutants homozygous for the Ljsym4-2 allele, arbuscule formation was never observed upon inoculation with either of the two AM fungi, Glomus intraradices or Gigaspora margarita. The strategy of epidermal penetration by G. margarita was identical for Ljsym4-2 mutants and the parental line, with appressoria, hyphae growing between two epidermal cells, penetration of epidermal cells through their anticlinal wall. These observations define a novel, genetically controlled step in AM colonization. Although rhizobia penetrate the tip of root hairs and AM fungi access an entry site near the base of epidermal cells, the LjSym4 gene is necessary for the appropriate response of this cell type to both microsymbionts. We propose that LjSym4 is required for the initiation or coordinated expression of the host plant cell's accommodation program, allowing the passage of both microsymbionts through the epidermis layer.

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