Plant–microbe interactions promoting plant growth and health: perspectives for controlled use of microorganisms in agriculture

Abstract

Plant-associated microorganisms fulfill important functions for plant growth and health. Direct plant growth promotion by microbes is based on improved nutrient acquisition and hormonal stimulation. Diverse mechanisms are involved in the suppression of plant pathogens, which is often indirectly connected with plant growth. Whereas members of the bacterial genera Azospirillum and Rhizobium are well-studied examples for plant growth promotion, Bacillus, Pseudomonas, Serratia, Stenotrophomonas, and Streptomyces and the fungal genera Ampelomyces, Coniothyrium, and Trichoderma are model organisms to demonstrate influence on plant health. Based on these beneficial plant-microbe interactions, it is possible to develop microbial inoculants for use in agricultural biotechnology. Dependent on their mode of action and effects, these products can be used as biofertilizers, plant strengtheners, phytostimulators, and biopesticides. There is a strong growing market for microbial inoculants worldwide with an annual growth rate of approximately 10%. The use of genomic technologies leads to products with more predictable and consistent effects. The future success of the biological control industry will benefit from interdisciplinary research, e.g., on mass production, formulation, interactions, and signaling with the environment, as well as on innovative business management, product marketing, and education. Altogether, the use of microorganisms and the exploitation of beneficial plant-microbe interactions offer promising and environmentally friendly strategies for conventional and organic agriculture worldwide.

Exploring functional contexts of symbiotic sustain within lichen-associated bacteria by comparative omics

“…Using our multiphasic approach, combining omics technologies and physiological assays, we found diverse and previously unknown potential functions of the microbiome, such as nutrient supply, resistance against biotic and abiotic stress, support for the photosynthesis and for the growth of the two eukaryotic partners, as well as detoxification and thallus degradation abilities. Supportive roles of associated microbiomes are well-known from humans, animals and plants (Berg, 2009;Bragina et al, 2013;Cho and Blaser, 2012). With our present results, we have found new hints that a similar helper effect can be present in lichen symbioses.…”

Pythium oligandrum: an example of opportunistic success

“…While the beneficial effects of rhizobacteria and true fungi such as species in the genus Trichoderma have been abundantly explored (Berg, 2009;Lorito et al, 2010), the possibility that selected members of the oomycetes may contribute to protecting plants from infection has often been ignored by plant pathologists who long considered that oomycetes were essentially virulent pathogens (Blair et al, 2008;Latijnhouwers et al, 2003). In the past few years, however, the field of beneficial plant-oomycete interactions has started to be the focus of interest and it is anticipated that scientists from both fields will work together to provide an integrated view of the molecular mechanisms that evolved in pathogenic and beneficial plant-oomycete interactions.…”

Establishment of Antifungal Phyllospheric Bacteria in Potato (Solanum tuberosum L.)

“…Phyllosphere bacteria can affect plant growth indirectly by protecting plants against pathogens. These microbial communities may be involved in plant protection, due to direct interactions of resident microorganisms those produce antibiotic compounds and showed competition for resources (Berg, 2009). Such antagonistic effects have been demonstrated for several leaf-colonizing bacterial isolates.…”

“…Also, indole-3-acetic acid (IAA), the major naturally occurring auxin, is a signalling molecule in microorganisms because IAA affects gene expression in some microorganisms (Spaepen and Vanderleyden, 2016). They can also be involved in plant protection, which is due to direct interactions of microorganisms through the production of antibiotic compounds and competition for resources (Berg, 2009). Additionally, microorganisms may protect plants against the pathogens by inducing systemic resistance (Conrath et al, 2006;Pieterse et al, 2012).…”