Brief Overview of Arbuscular Mycorrhiza Research Conducted in Russia Over the XXTH Century

Abstract

Arbuscular mycorrhiza (AM) is one of the most common terrestrial plant-microbe symbioses. The interest in studying AM is caused by its importance for the growth and nutrition of plants and its ecological role in preserving biological diversity. At present, 92% of plant families are known to form AM. Fungi in AM are obligate symbionts and belong to a monophyletic group – Glomeromycotina subdivision. Some researchers believe that formation of AM-symbiosis with fungi by ancient plants allowed them to inhabit land, which has led to the formation of the biosphere as we know it. AM is studied by researchers from around the world including Russia. This overview presents in brief the results of AM research in Russia during the Soviet period which did not receive international coverage due to its classified nature; the most prominent research schools and works of AM researchers are identified; main stages and lines of this research are listed, such as: distribution of AM in plant communities and different climatic zones, mycorrhiza anatomy and morphology, fungi species composition on different soils, collection of AM fungi and growing AM in vitro, physiological role of AM for agricultural plants, the impact different ecological factors have on AM fungi species composition and AM development, conditions for effective use of Am fungi to increase productivity and quality of agricultural plants as well as to perform biological recultivation of toxic soils and restore the fertility of degraded soils.

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

“…At the flowering stage, the group still did not show downregulation of genes, but the number of upregulated genes shifted down significantly (2.3 times). The high expression of the genes gathered in the "Protein biosynthesis" group also confirms our assumption that mycorrhization provides better growth conditions with a better supply of mineral nutrients to the plant and thereby stimulates biosynthetic processes [29]. Meanwhile, in the less-responsive-to-inoculation system "M. truncatula + R. irregularis", at 30 DAS, in the study of L. Adolfsson et al, it was shown that only a quarter of the genes were characterized by upregulation in the "Protein biosynthesis" group [57].…”

“…The analysis of protein biosynthesis genes showed an intensive upregulation of genes involved in the biosynthesis of small and large ribosomal subunits (SSU and LSU, respectively) at the second leaf stage. Previously, it was also shown that at this stage (24 DAS), the AM plants M. lupulina already have more developed leaves, accelerated development in comparison with control plants not inoculated with AM fungus, and enlargement in leaf surface area [29]. This coincided with the enhancement of photosynthetic processes in mycorrhized plants.…”

“…The clustering of various groups of metabolites, discovered earlier, demonstrated the central role of amino acid-carboxylate and carbohydrate clusters at the early and late stages of M. lupulina development. A higher content of serine, methionine, histidine, and other nitrogen-containing compounds was detected in comparison with non-mycorrhized plants, as well as GABA, cyanoalanine, oxoproline, and arginine, at the second leaf development stage [29]. It is noteworthy that none of the amino acids had lower contents under AM at the same time at the early and late stages.…”

“…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].…”