Transcription of two blue copper-binding protein isogenes is highly correlated with arbuscular mycorrhizal development in Medicago truncatula.
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.
Parádi
István
I
UMR 1088 INRA/5184 CNRS/Université de Bourgogne, Plante-Microbe-Environnement, INRA-CMSE, Dijon BP 86510, 21065 Dijon Cedex, France. iparadi@caesar.elte.hu
van Tuinen
Diederik
D
Morandi
Dominique
D
Ochatt
Sergio
S
Robert
Franck
F
Jacas
Louis
L
Dumas-Gaudot
Eliane
E
D002352:Carrier Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D046913:Medicago truncatula / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D038821:Mycorrhizae / Q000502:physiology*; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D020033:Protein Isoforms; D014158:Transcription, Genetic
D002352:Carrier Proteins; D010940:Plant Proteins; D020033:Protein Isoforms; C023548:copper-binding protein