Biocontrol of Plant Pathogens Using Plant Growth Promoting Bacteria

Abstract

Food is the primary requirement for the survival of mankind. Therefore food has always been an issue since prehistoric times. Food production through agriculture is a key process to meet the world food demand. In the last four to fi ve decades global agricultural production has been drastically improved by introduction of improved crop varieties and development of modern agricultural tools. However, more than 25% of the crop yield is lost every year due to various kinds of plant diseases. Most critical plant diseases are caused by soilborne plant pathogens such as fungi, virus and nematodes. Effective measures are thus highly needed to avoid this crop loss. So far, the use of chemical pesticides has been the method of choice to tackle this problem. However, the unwarranted use of chemical tools to enhance the crop yield and control plant diseases has resulted in irreversible loss of soil quality along with serious health and environmental problems. Moreover, alternative controls are needed due to growing public concern about toxic agrochemicals and stringent laws. Microbes are a reasonable option to develop ecofriendly agricultural tools to replace chemical pesticides.Here we review the role of a special class of soil bacteria, called plant growth promoting rhizobacteria (PGPR). PGPR live in the rhizospheric sites in soil, i.e. in immediate vicinity of the plant roots, and exerts several bene fi cial effects on the plants, directly or indirectly. PGPR have inherent antagonistic properties against soilborne plant pathogens under natural conditions. The major points discussed here are: (1) biocontrol of plant pathogens as an alternative to chemical control methods.(2) The current market status of various biocontrol products with a noticeable increase of 80% market share in 5 years. (3) The success of PGPR to protect many plant species, against diverse range of plant pathogens. (4) Mechanisms underlying the control and inhibition of soilborne plant pathogens including antagonistic activities such as production of antibiotics, offering stiff competition to the pathogen for nutrients and niches in the rhizosphere, parasitism of the pathogen and induction of systemic resistance in the plants against diseases.

Plant Growth-Promoting Rhizobacteria: Context, Mechanisms of Action, and Roadmap to Commercialization of Biostimulants for Sustainable Agriculture

“…Over the long term, pathogen-antagonistic bacteria will also evolve their mode of action to counteract the pathogens. PGPR also produce antibiotics such as lipopeptides, polyketides and antifungal metabolites that suppress pathogens ( Prashar et al, 2013 ).…”

Biocontrol of Two Bacterial Inoculant Strains and Their Effects on the Rhizosphere Microbial Community of Field-Grown Wheat

“…Microbes accumulate in the rhizosphere and utilize root exudates released by their plant host(s) [ 3 ]. In return, plant-associated bacteria can promote plant growth via various mechanisms including (1) supplying nutrients to plants via nitrogen fixation and solubilization of mineral phosphate and potassium [ 4 , 5 ], (2) competing with pathogens for nutrients and niches [ 6 ], (3) suppressing pathogen proliferation by producing secondary metabolites such as antibiotics and hydrolytic enzymes [ 7 ], and (4) inducing systemic resistance [ 8 ]. Additionally, the generation of 1-aminocyclopropane-1-carboxylate deaminase (ACCD), indole acetic acid (IAA), and siderophores by plant growth-promoting rhizobacteria (PGPR) can directly or indirectly stimulate seedling growth [ 9 , 10 ].…”

Role of salicylic acid from Pseudomonas aeruginosa PF23EPS+ in growth promotion of sunflower in saline soils infested with phytopathogen Macrophomina phaseolina

“…SA a metabolite reported commonly to be produced by pseudomonads (Mehran et al 2013) and has a role in induce systemic resistance (Ran et al 2005;Schuhegger et al 2006;Shahzad et al 2017). The positive role of bacterial EPS, as an elicitor, for the induction of systemic resistance against various phytopathogens of different crop species has been reported by Prashar et al (2013), Thenmozhi and Dinakar (2014). EPS production under stress conditions act as a strategy to protect bacterial cells from salinity stress damages (Tewari and Arora 2014a;.…”