Molecular Mechanisms of Pseudomonas-Assisted Plant Nitrogen Uptake: Opportunities for Modern Agriculture

Abstract

Pseudomonas spp. make up 1.6% of the bacteria in the soil and are found throughout the world. More than 140 species of this genus have been identified, some beneficial to the plant. Several species in the family Pseudomonadaceae, including Azotobacter vinelandii AvOP, Pseudomonas stutzeri A1501, Pseudomonas stutzeri DSM4166, Pseudomonas szotifigens 6HT33bT and Pseudomonas sp. K1 can fix nitrogen from the air. The genes required for these reactions are organized in a nitrogen fixation island, obtained via horizontal gene transfer from Klebsiella pneumoniae, Pseudomonas stutzeri and Azotobacter vinelandii. Today, this island is conserved in Pseudomonas spp. from different geographical locations, which in turn have evolved to deal with different geo-climatic conditions. Here, we summarize the molecular mechanisms behind Pseudomonas driven plant growth promotion, with particular focus on improving plant performance at limiting nitrogen (N), and improving plant N content. We describe Pseudomonas-plant interaction strategies in the soil, noting that the mechanisms of denitrification, ammonification, and secondary metabolite signalling are only marginally explored. Plant growth promotion is dependent on the abiotic conditions, and differs at sufficient and deficient N. The molecular controls behind different plant response are not fully elucidated. We suggest that superposition of transcriptome, proteome, and metabolome data and their integration with plant phenotype development through time will help fill these gaps. The aim of this review is to summarize the knowledge behind Pseudomonas driven nitrogen fixation and to point to possible agricultural solutions

High-throughput sequencing-based analysis of the composition and diversity of the endophyte community in roots of Stellera chamaejasme

“…These findings also highlight differences in endophyte community composition between regions, with specific genera being more abundant in specific regions. Pseudomonas belongs to the phylum Proteobacteria, and previous studies have shown that Pseudomonas can produce siderophores 55 , dissolve phosphate 56 , fix nitrogen 57 , and transport soil nutrients into plants to promote plant growth. grow and protect plants against pathogenic bacteria 58 , suggesting that Pseudomonas species, which are dominant in S. chamaejasme , may play an important role in S. chamaejasme growth and disease resistance, thereby enhancing its ability to compete for habitat.…”

The Beneficial Fungus Mortierella hyalina Modulates Amino Acid Homeostasis in Arabidopsis under Nitrogen Starvation

“…Subsequently, many different aminotransferases distribute the amino group within the various amino acids and later into the whole plant metabolism. Thus, it was interesting to analyze the amino acid profile in the plants with and without fungal colonization as also postulated for interactions with beneficial bacteria [33]. The results obtained show clearly the N starvation effect on the Arabidopsis plants.…”

“…The sample element amounts were scaled against an in-house standard "Ali-j3" (Acetanilide) with δ 15 N values of −1.51 ± 0.1‰ on the δ 15 N AIR-N2 scales. "caf-j3" A (caffeine) sample was analyzed as a quality control with values of −15.46 ± 0.1‰ on the δ 15 N AIR-N2 scales [33]. Linearity, blank and drift corrections were undertaken for each sequence according to Werner and Brand (2001) [40].…”

Genome Analysis of Pseudomonas viciae G166 Conferring Antifungal Activity in Grapevine

“…Pseudomonas is a universal genus in different ecological niches and exhibits a versatile metabolic capacity [ 9 ]. A number of pseudomonas strains function as PGPRs to protect plants from various pathogens and/or stimulate plant growth [ 10 , 11 , 12 , 13 , 14 , 15 ]. For example, P .…”

“…For example, P . chlororaphis [ 11 ] and P. protegens [ 10 , 12 ] are non-pathogenic biocontrol agents, while several strains of P. stutzeri [ 14 , 15 ] show strong plant-growth-promoting activities. Bioactive secondary metabolites are the major defense mechanism against pathogenic microorganisms.…”