Fate and behaviour of a seed-appliedPseudomonas brassicacearumstrain in a winter wheat field trial, as determined by analysis with SCAR markers

Persistence ofPseudomonas fluorescensLBUM677 in the rhizosphere of corn gromwell (Buglossoides arvensis) under field conditions and its impact on seed oil and stearidonic acid bioaccumulation

“…The detected population levels for the two highest applied concentrations (the equivalent of 6 9 10 9 and 6 9 10 10 bacteria per seed) were found to be significantly higher than the control values. The population levels detected in our study are lower than those obtained by Johnsson Holmberg et al (2012), who found P. brassicacearum MA250 at levels of 10 6 -10 7 cells on winter wheat roots. However, our values are similar to those obtained by Mosimann et al (2017) who found a population size of P. fluorescens Pf153 between 1Á2 9 10 5 and 4Á8 9 10 5 colony-forming units (CFU) per gram of rhizosphere soil after growing maize plants for 8 weeks in a pot assay.…”

“…Pseudomonas sp., as any PGPR, are required to undergo thorough characterization before they can be approved and registered as commercial biofertilizers (Mathre et al 1999). Field studies tracking the fate of inoculated micro-organisms are valuable in determining their potential spread, persistence and rhizocompetence (Johnsson Holmberg et al 2012). Most studies conducted to date on the survival and persistence of selected microorganisms in the rhizosphere of plants have, however, been conducted in the laboratory or in controlled environments (growth chambers), often for short periods of time (Grosch et al 2007;Felici et al 2008).…”

The persistence and performance of phosphate-solubilizing Gluconacetobacter liquefaciens qzr14 in a cucumber soil

“…Several applications of PGPMs into soils had been successful; i.e., these have resulted in the colonization of soil and plant roots to a level sufficiently high for the intended purpose (Bhattacharjee et al 2012;Chabot et al 1996;Luna et al 2012). However, various failures or inconsistencies in achieving the objective have also been reported (Holmberg et al 2012;Vanelsas et al 1986;Von Felten et al 2010). For example, Burkholderia tropica increased tomato fruit yields by 17% in the first year, but only 6% in the second year (Bernabeu et al 2015).…”

Ecological arguments to reconsider data requirements regarding the environmental fate of microbial biocontrol agents in the registration procedure in the European Union

“…The best approach for this is to design a SCAR (specific-characterised-amplifiedregion) marker that can be amplified from samples. This approach was used for example for Trichoderma atroviride (Cordier et al 2007), Fusarium oxysporum (Edel-Hermann et al 2011), Pseudomonas brassicacearum (Holmberg et al 2012) and Bacillus amyloliquefaciens (Gotor-Vila et al 2016). A further essential step will be the species-or strain-specific quantification of DNA gene sequences using techniques that distinguish between living and dead cells (Daranas et al 2018).…”

“…Pseudomonas brassicacearum MA250 is an antagonist of Microdochium nivale causing snow mould in winter cereals (Holmberg et al 2012). Population studies using strain-specific qPCR were conducted in a field trial with antagonist-coated winter wheat seeds.…”