RESEARCH

Field tests

First field data indicate

• SEEDJECTIONTM does not negatively influence germination, emergence or crop quality
• Bacteria as well as fungi can be injected into seeds via the SEEDJECTIONTM technology
• The model strain Paraburkholderia phytofirmans PsJN shows very good colonization of root tissues
• Depending on injected strains, low cell numbers of already 102-103 cfu per seed are sufficient to achieve good colonization of the root tissue
• Better colonization of the inoculant strain (tested with PsJN) compared to seed coating application
• Good storability and viability, as well as high survival rates of the inoculant strain in the seeds treated with SEEDJECTIONTM could be demonstrated

Microbial colonization on and inside plants

The plant is colonized by a plethora of microorganisms such as fungi, bacteria, archaea, oomycetes, and viruses that are detrimental or beneficial for their hosts (Hardoim et al. 2015; Brader et al., 2017). Some of these microorganisms colonize the plant surfaces before to enter inside plant tissues and form assemblages of subcommunities in various organs. Each step of the colonization of some of these microorganisms has been studied using single cells or natural communities. Different fluorescence techniques such as the use of tagged strains, fluorescence in situ hybridization or general staining techniques coupled with confocal microscopy have enabled to determine the colonization of these microorganisms (Compant et al., 2010).

For bacteria, tagging of strains have been also done and a thorough understanding of the niches and ways of colonization of some specific plant-associated bacteria has been revealed (Compant et al., 2010; Escobar Rodríguez et al., 2018).

References

Brader G, Compant S, Vescio K, Mitter B, Trognitz F, Ma L, Sessitsch A. Ecology and genomic insights of plant-pathogenic and -nonpathogenic endophytes. Annual Review of Phytopathology (2017) 55: 61-83.

Compant S, Clément C, Sessitsch A. Plant growth-promoting bacteria in the rhizo- and endosphere of plants. Their role, colonization, mechanisms involved and prospects for utilization. Soil Biology and Biochemistry (2010) 42: 669-678.

Escobar Rodríguez C, Mitter B, Barret M, Sessitsch A, Compant S. Commentary: seed bacterial inhabitants and their routes of colonization. Plant and Soil (2018) 422: 129-134.

Hardoim Pr, Van Overbeek Ls, Berg G, Pirttilä Am, Compant S, Campisano A, Döring M,  Sessitsch A. The hidden world within plants: ecological and evolutionary considerations for defining functioning of microbial endophytes. Microbiology and Molecular Biology Reviews (2015) 79: 293-320.

Pierron R, Gorfer M, Berger H, Jacques A, Sessitsch A, Strauss J, Compant S. Deciphering the niches of colonisation of Vitis vinifera L. by the esca-associated fungus Phaeoacremonium aleophilum using a gfp marked strain and cutting systems. Plos One (2015) 10: E0126851.

Vacher C, Hampe A, Porté Aj, Sauer S, Compant S, Morris Ce. The phyllosphere: microbial jungle at the plant-climate interface. Annual Review of Ecology, Evolution, and Systematic (2016) 47: 1-24.