Pseudomonas fluorescens LBUM677 differentially increases plant biomass, total oil content and lipid composition in three oilseed crops

Abstract

Aims Pseudomonas spp. have been widely studied for their plant growth–promoting effects. However, their capacity to promote lipid accumulation in oilseed crops is not well characterized. In this study, we evaluated the effect of Pseudomonas fluorescens LBUM677 on lipid accumulation in three oilseed crops: soybean (Glycine max), canola (Brassica napus) and corn gromwell (Buglossoides arvensis), a plant of high nutraceutical interest for its accumulation of the omega‐3 stearidonic acid. Methods and Results Pot experiments were conducted under controlled conditions where seeds were inoculated or not with LBUM677 and plants were harvested at 4, 8 and 12 weeks. A qPCR assay specifically targeting LBUM677 was used in parallel to correlate LBUM677 soil rhizosphere competency to growth promotion and seed lipid accumulation. Total oil seed content and fatty acid composition were analysed at seed maturity. Results showed that LBUM677 was able to establish itself in the rhizosphere of the three plant species at similar levels, but it differentially increased plant biomass, total oil content and lipid composition in a plant‐specific manner. Conclusions Despite some species‐specific differences observed in P. fluorescens LBUM677's effect on different crops, the strain appears to be a generalist plant growth–promoting rhizobacteria of oilseed crops. Significance and Impact of the Study LBUM677 shows great potential to be used as an inoculum to promote oil yield and fatty acid accumulation in oilseed crops.

Inoculation With the Plant-Growth-Promoting Rhizobacterium Pseudomonas fluorescens LBUM677 Impacts the Rhizosphere Microbiome of Three Oilseed Crops

“…The results seem to suggest a confounding effect of sampling time and LBUM677 inoculation on the diversity of the rhizosphere microbiomes. This is in part surprising since a general decrease in the population levels of LBUM677 over time in these conditions was also previously demonstrated ( Jiménez et al, 2020 ). In this context, it would be expected that this reduction in the population levels of LBUM677 would not increasingly impact on the rhizosphere microbiome diversity over time.…”

“…A previous study examining the effect of LBUM677 on B. napus, B. arvensis , and G. max has shown that this bacterium is a successful PGPR inoculant. Specifically, LBUM677 can significantly increase seed oil yield and fatty acids content of the three different plants ( Jiménez et al, 2020 ). Additionally, LBUM677 demonstrated certain general plant growth promotion properties, including significantly increasing total plant weight in B. napus and B. arvensis , but not in G. max .…”

“…Additionally, LBUM677 demonstrated certain general plant growth promotion properties, including significantly increasing total plant weight in B. napus and B. arvensis , but not in G. max . LBUM677 was also found to persist to a similar level in the rhizosphere of the three plants, even though there was a general decrease in its population levels over time ( Jiménez et al, 2020 ). Following the demonstration that LBUM677 is an effective PGPR capable of significantly increasing seed oil accumulation in these three oilseed crops, it was logical to subsequently examine its possible non-target effects on the indigenous soil microbial populations of these three plant species.…”

“…We have previously demonstrated that P. fluorescens strain LBUM677 (hereafter LBUM677) can significantly promote lipid accumulation in three different oilseed crops ( Jiménez et al, 2020 ): canola ( Brassica napus L.) and soybean ( Glycine max L.), two crops with a considerable seed oil content and great commercial importance ( Ruddle et al, 2013 ), as well as corn gromwell ( Buglossoides arvensis L.), an oilseed crop with an increasing nutraceutical interest due to its unusual seed accumulation of the omega-3 stearidonic acid ( Cumberford and Hebard, 2015 ). In the present study, we wanted to determine the effect of LBUM677’s inoculation over time on the indigenous rhizosphere bacterial communities associated with these three different oilseed crops.…”

Long Term Comparison of Talc- and Peat-Based Phytobeneficial Pseudomonas fluorescens and Pseudomonas synxantha Bioformulations for Promoting Plant Growth

“…Our research group has thoroughly examined the plant growth promoting effects of two strains of Pseudomonas species, Pseudomonas fluorescens LBUM677 and Pseudomonas synxantha LBUM223. Previous studies conducted with LBUM677 have shown that in addition to plant growth promotion properties, the bacterium is able to increase seed oil content in various oilseed plants, including in corn gromwell (Buglossoides arvensis), a plant of high nutraceutical interest, under various field settings Filion, 2018, 2019;Jiménez et al, 2020). LBUM223 has demonstrated plant growth promotion properties and has been successful in reducing the symptoms of the bacterial pathogen Streptomyces scabies on potato plants in controlled and field settings (St-Onge et al, 2010Arseneault et al, 2015).…”