Transcription of Two Blue Copper-Binding Protein Isogenes Is Highly Correlated with Arbuscular Mycorrhizal Development in Medicago truncatula

Abstract

Expression profiling of two paralogous arbuscular mycorrhizal (AM)-specific blue copper-binding gene (MtBcp1a and MtBcp1b) isoforms was performed by real-time quantitative polymerase chain reaction in wild-type Medicago truncatula Jemalong 5 (J5) during the mycorrhizal development with Glomus intraradices for up to 7 weeks. Time-course analysis in J5 showed that expression of both MtBcp1 genes increased continuously and correlated strongly with the colonization intensity and arbuscule content. MtPT4, selected as a reference gene of the functional plant-fungus association, showed a weaker correlation to mycorrhizal development. In a second experiment, a range of mycorrhizal mutants of the wild-type J5 was assessed. Strictly AM-penetration-defective TRV25-C and TRV25-D (dmi3, Mtsym13), hypomycorrhizal TR25 and TR89 (dmi2, Mtsym2) mutants, and a hypermycorrhizal mutant TRV17 (sunn, Mtsym12) were compared with J5 3 and 7 weeks after inoculation. No MtBcp1 transcripts were detected in the mutants blocked at the appressoria stage. Conversely, TR25, TR89, and J5 showed a gradual increase of the expression of both MtBcp1 genes in 3- and 7-week-old plants, similar to the increase in colonization intensity and arbuscule abundance. The strong correlation between the expression level of AM-specific blue copper-binding protein-encoding genes and AM colonization may imply a basic role in symbiotic functioning for these genes, which may serve as new molecular markers of arbuscule development in M. truncatula.

Molecular dialogue between arbuscular mycorrhizal fungi and the nonhost plant Arabidopsis thaliana switches from initial detection to antagonism

“…Analysis of the transcriptional profile of Medicago roots revealed 4953 DEGs, of which 3168 genes were upregulated and 1785 genes were downregulated in response to Rhizophagus inoculation (Table S2). Among the upregulated Medicago genes are CCD7 , CCD8 , PT4 and BCP1 , which have previously been found to be upregulated in response to AM fungi (Harrison et al ., ; Parádi et al ., ; Bonneau et al ., ). In agreement with the much lower root colonization frequency, the transcriptome changes in Arabidopsis roots in response to Rhizophagus inoculation were markedly smaller, but still consisted of 954 DEGs, 414 of which were upregulated and 540 of which were downregulated (Table S2).…”

Local endoreduplication as a feature of intracellular fungal accommodation in arbuscular mycorrhizas

“…First, we confirmed the occurrence (in the WT) or lack of AM colonization (in both mutants) by analyzing the expression of two acknowledged plant symbiotic markers (Fig. S3a,b): the Blue Copper‐binding Protein MtBCBP (Parádi et al ., ), an early marker of cortex colonization and arbuscule development, and the E3 ubiquitin ligase MtPUB1 (Vernié et al ., ), an interactor of DMI2.…”

The Petunia GRAS Transcription Factor ATA/RAM1 Regulates Symbiotic Gene Expression and Fungal Morphogenesis in Arbuscular Mycorrhiza

“…We examined the expression of eight arbusculeassociated marker genes, PT4, PT5, RAM2, STR, STR2, VAPYRIN (see references above), subtilase (Takeda et al, 2007), and a BCP (Parádi et al, 2010), all representing conserved AM-responsive marker genes (Breuillin et al, 2010). Despite efficient colonization from nurse plants (Fig.…”