To improve access to limiting nutrients, the vast majority of land plants forms arbuscular mycorrhizal (AM) symbioses with Glomeromycota fungi. We show here that AM-related GRAS transcription factors from different subgroups are upregulated during a time course of mycorrhization. Based on expression studies in mutants defective in arbuscule branching (ram1-1, with a deleted MtRam1 GRAS transcription factor gene) or in the formation of functional arbuscules (pt4-2, mutated in the phosphate transporter gene MtPt4), we demonstrate that the five AM-related GRAS transcription factor genes MtGras1, MtGras4, MtGras6, MtGras7, and MtRad1 can be differentiated by their dependency on MtRAM1 and MtPT4, indicating that the network of AM-related GRAS transcription factors consists of at least two regulatory modules. One module involves the MtRAM1- and MtPT4-independent transcription factor MtGRAS4 that activates MtGras7. Another module is controlled by the MtRAM1-and MtPT4-dependent transcription factor MtGRAS1. Genome-wide expression profiles of mycorrhized MtGras1 knockdown and ram1-1 roots differ substantially, indicating different targets. Although an MtGras1 knockdown reduces transcription of AM-related GRAS transcription factor genes including MtRam1 and MtGras7, MtGras1 overexpression alone is not sufficient to activate MtGras genes. MtGras1 knockdown roots display normal fungal colonization, with a trend towards the formation of smaller arbuscules.
Insights into the complex role of GRAS transcription factors in the arbuscular mycorrhiza symbiosis / R.M. Hartmann, S. Schaepe, D. Nübel, A.C. Petersen, M. Bertolini, J. Vasilev, H. Küster, N. Hohnjec. - In: SCIENTIFIC REPORTS. - ISSN 2045-2322. - 9(2019 Mar 04).
|Titolo:||Insights into the complex role of GRAS transcription factors in the arbuscular mycorrhiza symbiosis|
|Settore Scientifico Disciplinare:||Settore BIO/18 - Genetica|
|Data di pubblicazione:||4-mar-2019|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1038/s41598-019-40214-4|
|Appare nelle tipologie:||01 - Articolo su periodico|