Effects of growth promoting microorganisms on tomato seedlings growing in different media conditions

PLoS One. 2021 Nov 3;16(11):e0259380. doi: 10.1371/journal.pone.0259380. eCollection 2021.

Abstract

Plant growth-promoting microbes (PGPM) play vital roles in maintaining crop fitness and soil health in stressed environments. Research have included analysis-based cultivation of soil-microbial-plant relationships to clarify microbiota potential. The goal of the research was to (i) evaluate the symbiotic microorganism effects on tomato seedling fitness under stressed conditions simulating a fragile soil susceptible to degradation; (ii) compare the plant-microbial interactions after inoculation with microbial isolates and fungi-bacteria consortia; (iii) develop an effective crop-microbial network, which improves soil and plant status. The experimental design included non-inoculated treatments with peat and sand at ratios of 50:50, 70:30, 100:0 (v:v), inoculated treatments with arbuscular mycorrhizal fungi (AMF) and Azospirillum brasilense (AZ) using the aforementioned peat:sand ratios; and treatment with peat co-inoculated with AMF and Saccharothrix tamanrassetensis (S). AMF + AZ increased root fresh weight in peat substrate compared to the control (4.4 to 3.3 g plant-1). An increase in shoot fresh weight was detected in the AMF + AZ treatment with a 50:50 peat:sand ratio (10.1 to 8.5 g plant-1). AMF + AZ reduced antioxidant activity (DPPH) (18-34%) in leaves, whereas AMF + S had the highest DPPH in leaves and roots (45%). Total leaf phenolic content was higher in control with a decreased proportion of peat. Peroxidase activity was enhanced in AMF + AZ and AMF + S treatments, except for AMF + AZ in peat. Microscopic root assays revealed the ability of AMF to establish strong fungal-tomato symbiosis; the colonization rate was 78-89%. AMF + AZ accelerated K and Mg accumulation in tomato leaves in treatments reflecting soil stress. To date, there has been no relevant information regarding the successful AMF and Saccharothrix co-inoculation relationship. This study confirmed that AMF + S could increase the P, S, and Fe status of seedlings under high organic C content conditions. The improved tomato growth and nutrient acquisition demonstrated the potential of PGPM colonization under degraded soil conditions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Azospirillum brasilense / physiology*
  • Culture Media, Conditioned / chemistry*
  • Magnesium / chemistry
  • Mycorrhizae / physiology*
  • Peroxidase / metabolism
  • Phenol / analysis
  • Plant Leaves / chemistry
  • Plant Leaves / growth & development
  • Plant Leaves / microbiology
  • Potassium / chemistry
  • Seedlings / growth & development
  • Solanum lycopersicum / chemistry
  • Solanum lycopersicum / growth & development*
  • Solanum lycopersicum / microbiology
  • Symbiosis

Substances

  • Culture Media, Conditioned
  • Phenol
  • Peroxidase
  • Magnesium
  • Potassium

Grants and funding

This paper was supported by project of Internal grant agency of Faculty of Horticulture, Mendel University in Brno IGA - ZF/2020 - AP004 (RP). Microscopic analyses were done on infrastructure supported by project OP VVV CZ.02.1.01/0.0/0.0/16_017/0002334. Research infrastructure for young scientists, financed from structural funds of EU and Ministry of education of the Czech Republic (RP). The paper was supported by Polish-Czech Joint Research Project PPN/BCZ/2019/1/00014; Microorganisms biodiversity impact on soil conservation in agricultural crop system (AS). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.