An international research team led by the Netherlands Institute of Ecology (NIOO-KNAW) is to search for invisible life in the Galápagos Islands. The diversity of bacteria and other microscopic organisms may not be evident to the naked eye, but it is essential to nature. To the islands' giant daisies, for instance: unique endemic plants that are currently under threat.

In Bio-Based Economy, plant materials are an essential resource for new industrial and sustainable applications. To ensure the production of sufficient plant biomass there is a need of mineral fertilizers. However, intensive fertilization causes leaching and run-off of nutrients, reduction in biodiversity, production of greenhouse gasses, global warming and changes in soil pH leading to environmental degradation. A key challenge is to intensify agricultural production methods in a way that minimizes harmful environmental effects of fertilizers. Therefore, there is an urgent need for new strategies that optimize plant growth and minimize abiotic and biotic factors that adversely affect plant growth and quality. The plant microbiome, i.e. the collective microbial communities associated with plants, harbors various fungal and bacterial genera that have beneficial effects on plant growth and health. Several bacterial genera promote plant growth and induce systemic resistance in plants against pathogens as well as insect pests. Recent 'omics'-based studies revealed that specific rhizobacteria cause substantial transcriptional changes in plants, leading to elevated levels of specific plant genes expression. Brazilian sugarcane production system is being developed towards to sustainable manner by recycling straw and vinasse (byproduct of ethanol industry), which combined practices allow less mineral fertilizers to be added into soil. In addition, the use of beneficial bacteria, such as plant growth promoting bacteria (PGPB) isolated from sugarcane rhizosphere has shown to increase plant growth and health under controlled situation. However, detailed investigation and fundamental understanding of the effect of these PGPB in different sugarcane genotypes in different soils containing different microbial community are urgent need. Therefore, this proposal aims to: (i) determine the effect of different soil microbial community composition on sugarcane growth inoculated with PGPB; (ii) identify the PGPB traits and genes involved in plant growth promotion; (iii) identify the plant traits and genes involved in plant growth promotion induced by PGPB. Potential applications of this proposal will be (i) the identified PGPB traits and genes to ensure or enhance plant biomass, yield and quality; (ii) the identified genotype-specific genes induced by PGPB responsible for enhancing plant productivity. The proposed project will provide new insights into mechanisms, traits and genes underlying PGPB-plant interactions and will yield new leads and tools to ensure/enhance sugarcane biomass for bio-based economy

The global saline-alkali land area has already exceeded 1.1 billion hectares. China has about 100 million hectares. Rice cultivation has been used as an effective strategy to amend saline-alkaline lands in northeastern Songnen Plain in China since the 1950s. However, it is not known the role of microbial functions during succession of soil restoration. The aim of this project is to fundamental understanding the microbial functions succession during the saline soil restoration.

Land degradation usually leads to a reduction in soil fertility, decline of plant productivity, and loss of biodiversity. Introducing beneficial microbial inoculants to degraded lands represents a promising and sustainable strategy. The aim of this project is to reveal the ecological roles of microbial inoculants and soil-resident microbial community in restoring both belowground biodiversity and aboveground productivity in the degraded land.

Unsustainable agricultural management practices such as non-conservationist tillage and overuse of fertilizers result in soil acidity and, in turn, soil degradation due to reduced carbon (C) concentrations and nutrient availability and increased aluminum toxicity. Application of lime (L) and phosphogypsum (PG) can overcome these constraints and improve soil quality, but the long-term effects of these amendments on both abiotic and biotic soil properties are not known, particularly when applied in combination. Here, we evaluate the effects of L (acidity corrective), PG (soil conditioner), and their combination (LPG) on soil organic matter (SOM) transformations, soil chemical and physical properties, microbiome assembly, N uptake by intercropped plants, maize yield, archaeal and bacterial abundances, and N cycle genes in the maize and ruzigrass rhizospheres in a long-term field experiment in tropical soil with a no-till maize and forage ruzigrass intercropping system. 

Soil phosphorus (P) availability may limit plant growth and alter root-soil interactions and rhizosphere microbial community composition. The composition of the rhizosphere microbial community can also be shaped by plant genotype. In this project we examine the rhizosphere bacterial and fungal including Arbuscular Mycorhizal Fungi (AMF) communities of young plants of 24 species of eucalypts (22 Eucalyptus and two Corymbia species) under low or sufficient soil P availability.

The aim of this research is to understand how cover crop species combined with different times of N application affect the cover crop straw, nutrition and productivity of cash crop, soil chemical properties and soil microbial composition and function in a holistic approach of the entire agricultural system under tropical no-till system. Focus is on microbiome that immediately respond to the N application disturbances and in a long period to the plant cultivation, N inputs and soil properties changes. We use 3-year field experiment with palisade grass and ruzigrass cover crops and subsequent maize cash crop combined with different N management strategies to quantify the microbial genes of the N cycle and the bacterial and fungal communities’ structure and composition in the agricultural system.

The goal of this project is to decipher the role of fungal denitrifiers in N2O production from soils under sustainable management practices. Here we apply mesocosms experiments combined with SIP and meta-omics approaches targeting the functional genes of N cycle. In addition, we design primers for fungal denitrifiers based on complete fungal genomes and soil metagenomics data.  

The aim of this project is to determine the ecological relationship between bacteria and soil aggregates. We inoculate individual beneficial bacteria and different microbial communities from different natural soils in simulated Mars soil, attempting to explain their improvement in soil aggregate stability by bacterial exudates (EPS), necromass and microbial functional traits.

Sufficient Phosphorus (P) and Iron (Fe) supply is essential for crop production. Most of the P and Fe in soil is not readily available for the plant, making agriculture depending on inorganic fertilizers mainly derived from depletable resources. An alternative to this unsustainable practice is to use recycled compounds recovered during wastewater treatment. This project focuses on the use of the two recycled compounds struvite (MgNH4PO4·6H2O) and vivianite (Fe3(PO4)2·8H2O) which are both insoluble and hard to synchronize with the nutrient needs during early plant development. To increase efficient nutrient release of these recycled sources, we propose the use of microbes that can solubilize P and release siderophore, both recognized traits of plant growth promoting microbes. Several plant growth-promoting microbes have been isolated, but their transfer to agriculture, so far, resulted in an inconsistent success, due to competition or resistance of the resident soil microbiome to inoculants. This project will circumvent this challenge by steering the local microbiome with the addition of recycled nutrients and will further optimize the microbiome by microbial community breeding. Overall, this project will focus on identifying microbial community members with struvite and vivianite solubilizing function, optimizing these communities, determining the role of these communities on increasing the nutrient release as well as monitoring the recruitment of these beneficial microbes in the rhizosphere and the effect on plant growth.