Medicago lupulina lines with defects in the development of efficient arbuscular mycorrhiza

Abstract

Background. The work is aimed to solve actual problems in biology of arbuscular mycorrhiza (AM). Currently, a lot of mutants had been obtained in various plant model objects with defects in genes controlling AM development, however, the mechanisms controlling development of effective AM symbiosis are still unclear.
 Materials and methods. The authors conducted a mutagenesis in Medicago lupulina, a new convenient model plant for molecular-genetic studies. High mycotrophic M. lupulina line have early and high response to mycorrhization, high seed production, as well as signs of dwarfism under conditions without of AM and low level of phosphorus available for plants. This method allows visually to identify plant lines with defects in AM symbiosis.
 Results. 14 modes for mutagenesis by ethylmethanesulfonate were conducted. Usage of 3 mutagenesis modes allowed to obtain: productive M1 progeny with high part of viable seedlings (73.3%–86.0%); 1405 plants in M2 progeny.
 Conclusion. According to population analysis for mutant plants in M2 progeny (up to M9 generation) 15 plant lines were selected: one Myc– plant line unable to form AM symbiosis, 4 Pen– plant lines unable to form AM symbiosis, but characterized by appressoria formation; 3 Rmd– plant lines forming low-activity ineffective AM symbiosis; 3 Rmd– plant lines forming low-activity effective AM and 4 Rmd++ plant lines forming effective AM with high abundance of symbiotic structures (mycelium/arbuscules/vesicles) in the roots.