Plant growth-promoting rhizobacterium Pseudomonas PS01 induces salt tolerance in Arabidopsis thaliana

Abstract

ObjectivesPlant growth-promoting rhizobacteria (PGPR) may contribute to sustainable crop production by improving plant growth and/or plant tolerance to abiotic stresses. Soil salinity, which limits the productivity of crop plants, is one of the major concerns of modern agriculture, especially in countries heavily affected by climate change as Vietnam. Currently, only a few reports have studied local PGPR isolated in Vietnam, particular Pseudomonas. Therefore, our study aimed to isolate and identify a region-specific Pseudomonas strain and evaluate the effects of this strain on germination, growth promotion and gene expression of Arabidopsis thaliana under salt stress.ResultsThe Pseudomonas named PS01 was isolated from maize rhizosphere collected in Ben Tre province, Vietnam. This strain was identified as a member of the Pseudomonas putida subclade. Pseudomonas PS01 could improve the germination rate of Arabidopsis seeds in 150 mM NaCl. A. thaliana plants inoculated with Pseudomonas PS01 survived under salt stress conditions up to 225 mM NaCl, while all non-inoculated plants were dead above 200 mM NaCl. The transcriptional levels of genes related to stress tolerance showed that only LOX2 was up-regulated, while APX2 and GLYI7 were down-regulated in inoculated plants in comparison to the non-inoculated controls. In turn, RD29A and RD29B did not show any significant changes in their expression profiles.Electronic supplementary materialThe online version of this article (10.1186/s13104-019-4046-1) contains supplementary material, which is available to authorized users.

Pseudomonas PS01 Isolated from Maize Rhizosphere Alters Root System Architecture and Promotes Plant Growth

“…The results showed that after 2 days of incubation, a higher rate of germination was observed in bacteria coated seeds (51.5%), compared to uncoated seeds (31.3%) (n = 100) ( Figure S3). Previously, we reported the improvement of Arabidopsis germination rate in salt stress conditions by PS01 [45]. Here, we showed that after 30 days of growth in green-house conditions, inoculation of bacteria resulted in an increase in shoot and root dry weight by 1.4 fold and 2.2 fold, respectively (Figure 11a,b).…”

“…In the previous studies, we found that Pseudomonas strain PS01 could enhance plant growth in saline conditions, whereas Pseudomonas strains P112 and P113 (coded as PS02 and PS03 in this study) enhanced plant growth in normal conditions [35,45]. In this study, we evaluate plant growth-promoting (PGP) traits of these strains and 17 other strains which were isolated from the rhizosphere and rhizoplane of various crop plants.…”

“…These results reinforced the idea that PS01 could be used for the formulation of a new bio inoculant. Previously, we reported the ability of the PS01 strain in inducing a salt tolerance response in Arabidopsis thaliana [45]. However, successful application of this bacterium in soil conditions still requires further studies.…”

“…Therefore, it is important to isolate and identify region-specific microbial strains, which is capable of enhancing the crop yield of species adapted to specific ecological and environmental conditions. Currently, there are too few reports on PGP Pseudomonas isolated and characterized in the Mekong Delta [35,45]. In this study, a total of 20 strains were isolated from the rhizospheres of various plants and subjected to advance plant growth screening.…”

“…The genus Pseudomonas is very diverse and is still undergoing taxonomic refinement [46]. Previously, PS01 was identified as a member of the Pseudomonas putida group based on rpoD gene sequence [45]. In this study, to further refine the taxonomic classification of PS01, the whole genome of this strain had been sequenced.…”