The plasma membrane proteome of Medicago truncatula roots as modified by arbuscular mycorrhizal symbiosis

Abstract

In arbuscular mycorrhizal (AM) roots, the plasma membrane (PM) of the host plant is involved in all developmental stages of the symbiotic interaction, from initial recognition to intracellular accommodation of intra-radical hyphae and arbuscules. Although the role of the PM as the agent for cellular morphogenesis and nutrient exchange is especially accentuated in endosymbiosis, very little is known regarding the PM protein composition of mycorrhizal roots. To obtain a global overview at the proteome level of the host PM proteins as modified by symbiosis, we performed a comparative protein profiling of PM fractions from Medicago truncatula roots either inoculated or not with the AM fungus Rhizophagus irregularis. PM proteins were isolated from root microsomes using an optimized discontinuous sucrose gradient; their subsequent analysis by liquid chromatography followed by mass spectrometry (MS) identified 674 proteins. Cross-species sequence homology searches combined with MS-based quantification clearly confirmed enrichment in PM-associated proteins and depletion of major microsomal contaminants. Changes in protein amounts between the PM proteomes of mycorrhizal and non-mycorrhizal roots were monitored further by spectral counting. This workflow identified a set of 82 mycorrhiza-responsive proteins that provided insights into the plant PM response to mycorrhizal symbiosis. Among them, the association of one third of the mycorrhiza-responsive proteins with detergent-resistant membranes pointed at partitioning to PM microdomains. The PM-associated proteins responsive to mycorrhization also supported host plant control of sugar uptake to limit fungal colonization, and lipid turnover events in the PM fraction of symbiotic roots. Because of the depletion upon symbiosis of proteins mediating the replacement of phospholipids by phosphorus-free lipids in the plasmalemma, we propose a role of phosphate nutrition in the PM composition of mycorrhizal roots.

A rice Serine/Threonine receptor-like kinase regulates arbuscular mycorrhizal symbiosis at the peri-arbuscular membrane

“…The PAM marker ZmPT6 (GRMZM5G881088) was detected by 18 unique peptides (Table 1 ). Similarly, the maize homologs of the PAM-localized ABC transporters ZmSTR1 (GRMZM2G357034) and ZmSTR2 (GRMZM2G035276) 11 , 12 were reliably identified by 15 and 18 peptides each (Table 1 ), confirming the significantly improved sensitivity of our proteomics strategy 30 , 40 , 41 .

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Soil potassium is correlated with root secondary metabolites and root-associated core bacteria in licorice of different ages

“…Licorice ( Glycyrrhiza ) is a genus of herbaceous perennial plants in the family Leguminosae, with approximately 20 species known as popular medicinal plants in arid and semi-arid regions worldwide (Lewis et al, 2005 ; Xie et al 2018 ). Glycyrrhiza uralensis Fisch.…”

“…Therefore, the dynamics of the microbiome associated with medicinal plants have been explored extensively (Huang et al 2018 ; Koberl et al 2013 ). There are several studies that have reported the beneficial effects of arbuscular mycorrhizal symbiosis on plant growth and secondary metabolite accumulations in the roots of licorice (Chen et al 2017 ; Xie et al 2018 ). Other studies have shown that the growth and efficacy of the medicinal herb Danshen ( Salvia miltiorrhiza ) can be promoted by beneficial plant-associated microbes, such as those of the Pantoea , Pseudomonas , and Sphingomonas genera (Huang et al 2018 ).…”

Plant–Microbe Symbiosis: What Has Proteomics Taught Us?

“…Proteome analysis of endomembranes of M. truncatula during mycorrhization led to the identification of 882 and 650 putative membrane proteins, many of which perform fundamental roles in the complex network of AM interaction . Aloui et al . compared the protein profile of PM fractions of M. truncatula from AM ( Rhizophagus irregularis ) and nonmycorrhizal roots.…”