Mycorrhiza-Induced Alterations in Metabolome of Medicago lupulina Leaves during Symbiosis Development.

Andrey P Yurkov,Anastasia O Gorbunova,Yuri V Kosulnikov,Andrei P Kozhemyakov,Galina N Smolikova,Alexey A Kryukov,Roman K Puzanskiy,Maria F Shishova,Lidija M Jacobi,Daria A Romanyuk,Anastasia A Kirpichnikova,Vladislav V Yemelyanov,Galina S Avdeeva,Yuri V Laktionov,Alexey L Shavarda

doi:10.3390/plants10112506

Abstract

The present study is aimed at disclosing metabolic profile alterations in the leaves of the Medicago lupulina MlS-1 line that result from high-efficiency arbuscular mycorrhiza (AM) symbiosis formed with Rhizophagus irregularis under condition of a low phosphorus level in the substrate. A highly effective AM symbiosis was established in the period from the stooling to the shoot branching initiation stage (the efficiency in stem height exceeded 200%). Mycorrhization led to a more intensive accumulation of phosphates (glycerophosphoglycerol and inorganic phosphate) in M. lupulina leaves. Metabolic spectra were detected with GS-MS analysis. The application of complex mathematical analyses made it possible to identify the clustering of various groups of 320 metabolites and thus demonstrate the central importance of the carbohydrate and carboxylate-amino acid clusters. The results obtained indicate a delay in the metabolic development of mycorrhized plants. Thus, AM not only accelerates the transition between plant developmental stages but delays biochemical “maturation” mainly in the form of a lag of sugar accumulation in comparison with non-mycorrhized plants. Several methods of statistical modeling proved that, at least with respect to determining the metabolic status of host-plant leaves, stages of phenological development have priority over calendar age.

Highlights

Arbuscular mycorrhiza (AM) is one of the oldest forms of widespread symbiosis and was a factor in the land invasion of plants more than 400 million years ago [1]
R. irregularis inoculation stimulated the accumulation of these forms of phosphates in total for all general stages of development and for each stage separately (1L, Stooling Initiation (SI) and flowering initiation (FI)), and the response to mycorrhization was observed early, already at the first detection stage, 1st leaf (1L) at 14 day after sowing (DAS)
The results of the study indicate the suitability of using the highly sensitive M. lupulina MlS-1 line as a host plant to investigate the mechanisms of arbuscular mycorrhiza formation

Summary

Introduction

Arbuscular mycorrhiza (AM) is one of the oldest forms of widespread symbiosis and was a factor in the land invasion of plants more than 400 million years ago [1]. Most land plants form this symbiosis with fungi from the Glomeromycotina subdivision in the Mucoromycota division [2]. AM fungi are obligate symbionts and receive 4–20% of their photosynthetic products from the host plant in the form of glucose [8,9] and sucrose [8,10]. Recent investigations have revealed the possible signaling function of sugars and Pi starvation in the establishment of AM [8,13,14]. Close interaction between sugar and hormone signaling extend the possible means by which plant growth and development are regulated as well modulating the establishment of AM [15]

Methods

Results

Discussion

Conclusion