Promising bacterial genera for agricultural practices: An insight on plant growth-promoting properties and microbial safety aspects

Abstract

In order to address the ever-increasing problem of the world's population food needs, the optimization of farming crops yield, the combat of iron deficiency in plants (chlorosis) and the elimination/reduction of crop pathogens are of key challenges to solve. Traditional ways of solving these problems are either unpractical on a large scale (e.g. use of manure) or are not environmental friendly (e.g. application of iron-synthetic fertilizers or indiscriminate use of pesticides). Therefore, the search for greener substitutes, such as the application of siderophores of bacterial source or the use of plant-growth promoting bacteria (PGPB), is presented as a very promising alternative to enhance yield of crops and performance. However, the use of microorganisms is not a risk-free solution and the potential biohazards associated with the utilization of bacteria in agriculture should be considered. The present work gives a current overview of the main mechanisms associated with the use of bacteria in the promotion of plant growth. The potentiality of several bacterial genera (Azotobacter, Azospirillum, Bacillus, Pantoea, Pseudomonas and Rhizobium) regarding to siderophore production capacity and other plant growth-promoting properties are presented. In addition, the field performance of these bacteria genera as well as the biosafety aspects related with their use for agricultural proposes are reviewed and discussed.

Evaluation of Organic Substrates and Microorganisms as Bio-Fertilisation Tool in Container Crop Production

“…Table 5, of the enzyme results, shows that substrate 0:100 (VC:FC) had the lowest FTA, linked to phosphate mineralisation processes, as well as the lower concentration in PCE, and that by its very nature, this substrate did not have a positive effect on PGPBs as there were no statistical differences from the control ( Table 8). The maximum average value obtained by PGPB was 292 mg L −1 for BM, followed by FA (278 mg L −1 ) and AV (267 mg L −1 ), which are also associated with inorganic phosphate solubilisation capabilities [55], while the control recorded the lowest phosphate value of 245 mg L −1 in PCE. The solubilising capacity of phosphates by BM in substrates with VC was observed, by improving the nutritional status of the plants in the analyses at 90 and 120 DAT.…”

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

“…Regarding the potential health risk of PGPR to human, efforts in characterization of the isolates at the species level should be employed before proceeding with formulation development or pilot and largescale field level applications. Currently, agricultural microbiologists are mainly focused on the beneficial traits of the isolates while ignoring the possible existence of opportunistic human or animal pathogenicity [22,23]. Therefore, it is highly desirable to use phylogenomic data for exact taxonomy classification.…”

Isolation, Identification and Characterization of Endophytic Bacterium Rhizobium oryzihabitans sp. nov., from Rice Root with Biotechnological Potential in Agriculture

“…Plant growth-promoting rhizobacteria (PGPR) is a group of rhizosphere bacteria that can enhance plant growth by phosphate solubilization, siderophore production, biological nitrogen fixation, production of 1-aminocyclopropane-1-carboxylate (ACC) deaminase, and production of indole-3-acetic acid (IAA) [13]. Rhizobium is a well-known plant microbiota for nitrogen fixation traits with legume host and non-legume plant growth promoters [14][15][16]. Such as, Rhizobium leguminosarum trifolii E11 is able to promote rice plant growth by phosphate solubilization and IAA production; Bradyrhizobium japonicum can promote the growth of radishes by siderophore production [16], and so on.…”