The Role of Medicago lupulina Interaction with Rhizophagus irregularis in the Determination of Root Metabolome at Early Stages of AM Symbiosis

Abstract

The nature of plant–fungi interaction at early stages of arbuscular mycorrhiza (AM) development is still a puzzling problem. To investigate the processes behind this interaction, we used the Medicago lupulina MlS-1 line that forms high-efficient AM symbiosis with Rhizophagus irregularis. AM fungus actively colonizes the root system of the host plant and contributes to the formation of effective AM as characterized by a high mycorrhizal growth response (MGR) in the host plant. The present study is aimed at distinguishing the alterations in the M. lupulina root metabolic profile as an indicative marker of effective symbiosis. We examined the root metabolome at the 14th and 24th day after sowing and inoculation (DAS) with low substrate phosphorus levels. A GS-MS analysis detected 316 metabolites. Results indicated that profiles of M. lupulina root metabolites differed from those in leaves previously detected. The roots contained fewer sugars and organic acids. Hence, compounds supporting the growth of mycorrhizal fungus (especially amino acids, specific lipids, and carbohydrates) accumulated, and their presence coincided with intensive development of AM structures. Mycorrhization determined the root metabolite profile to a greater extent than host plant development. The obtained data highlight the importance of active plant–fungi metabolic interaction at early stages of host plant development for the determination of symbiotic efficiency.

The Effects of Rhizophagus irregularis Inoculation on Transcriptome of Medicago lupulina Leaves at Early Vegetative and Flowering Stages of Plant Development

“…Recently, various omics approaches have been widely used to study the function of supra-organismal symbiotic PMS, which is formed during the development of arbuscular mycorrhiza [23,26,27,[29][30][31][32]34,35]. These approaches include transcriptomic analysis, which identifies groups of DEGs that are significant for a plant upon interaction with AM fungus [33][34][35].…”

“…Special interest is always paid to the improvement of sequencing and transcriptome analyses [19][20][21][22][23]. Studies are underway investigating the influence of AM fungi on the proteome of M. truncatula, Pisum sativum [23][24][25][26][27], and on the metabolome (with gaschromatography-mass spectrometry, GC-MS) of M. truncatula, M. lupulina, P. sativum [26,[28][29][30][31][32], etc. The role of AM transcriptomic studies of M. truncatula, Nicotiana attenuata, P. sativum is remarkable [33][34][35].…”

“…The transcriptomic analysis of the model PMS "Medicago lupulina + Rhizophagus irregularis", with MGR > 350% under conditions of phosphorus (P) deficiency for plant nutrition is promising [46]. The micro-vegetative experiments in M. lupulina provided in our earlier experiments during the development of AM symbiosis showed significant changes in the course of development and hormonal rearrangements in the host plant [47,48]; metabolic rearrangements [30,49]; and changes in the expression of a number of genes for carbohydrate metabolism and P transport [50].…”

Symbiosis of Plants with Mycorrhizal and Endophytic Fungi

“…In this context, Yurkov et al [12] focused on the study of the interaction of the plant and the early stages of the development of arbuscular mycorrhizae (AM), studying the metabolome of the inoculated root of Medicago lupulina in a substrate with low phosphorus. The results obtained indicated that mycorrhization was the determinant of the root metabolite profile rather than the further development of the host plant.…”

Impact of Mycorrhizal Fungi from Different Rhizospheric Soils on Fungal Colonization, Growth, and Chlorophyll Contents of Cenchrus ciliaris

“…Arbuscular mycorrhizae are the associations where a Glomeromycete fungus produces arbuscules, hyphae, and vesicles within root cortex cells [11]. These associations are due to the presence of arbuscules.…”