Plants host diverse communities of microorganisms, also known as the microbiome, which colonizes various parts of host plants such as the rhizosphere, phyllosphere, and endosphere. The microbiome includes protists, fungi, bacteria, viruses, nematodes, etc. This highly complex assemblage of microorganisms has an important role in plant growth and health as well as in improving the productivity of crops by forming complex co-associations with plants. The plant-associated microbial communities confer multiple beneficial advantages to their host plants through nutrient acquisition, growth promotion, pathogen resistance, and environmental stress tolerance. Nowadays, a considerable amount of information is available on the structure and dynamics of the plant microbiome. The functional capacities of the isolated microbes have been identified using novel technologies.
The world population is estimated to rise to 9.5 billion by 2050, leading to high food demand. The availability of limited fertile land, urbanization, and climate change are some of the major constraints for the productivity of many crops. In addition, plants are subject to various biotic and abiotic stresses that limit their growth and productivity. The potential of the plant-associated microbial community to overcome biotic and abiotic stresses in plants can be interlinked to mitigate the current challenges in food security. For this, there is an urgent need to bring microbial innovations into practice.
Microbiome engineering is an emerging biotechnological strategy to improve the functional capabilities of native microbial species under biotic and abiotic stresses. It is a win-win strategy where both humans and the environment are benefited by improving crop yield and soil health. Conditioning the soil using suitable amendments, cultivating microbe-recruiting plant cultivars (host-dependent microbiome engineering), and inoculating synthetic microbial communities are microbiome approaches which improve plant health under stress conditions by increasing the functionally active and diverse microbial communities.
Figure 1 - Different microbiome engineering approaches
Traditional soil organic formulations such as compost, organic residues, organic waste, and peat can be used to support the growth and activation of beneficial soil microbes. Plant-oriented signaling molecules such as salicylic acid and metabolites in root exudates have a strong effect on the dynamics and the composition of the microbiome. It was suggested that these microbe-stimulating compounds can be artificially modulated and can be used as the soil conditioners.
Artificial microbial consortia (AMC) can also be used to improve the multiple functions relevant to crop plant growth and development. This strategy is the best alternative to solve the drawbacks of traditional bio fertilizers. Plant growth promoting rhizobacteria (PGPR) and AM fungi can also be artificially inoculated into soils to alter the structure of microbial communities. For example, inoculating chili plant roots with Bacillus amyloliquefaciens, Acinetobacter sp. and Bacillus velezensis have promoted the growth of chili plants and have shown the disease suppressive ability against Phytophthora capsica. Genetic engineering is also leading to the development of host-specific bio fertilizers.
References
Noman, M.; Ahmed, T.; Ijaz, U.; Shahid, M.; Azizullah; Li, D.; Manzoor, I.; Song, F. Plant–Microbiome Crosstalk: Dawning from Composition and Assembly of Microbial Community to Improvement of Disease Resilience in Plants. Int. J. Mol. Sci. 2021, 22, 6852. https://doi.org/10.3390/ijms22136852
Albright, M.B.N., Louca, S., Winkler, D.E. et al. Solutions in microbiome engineering: prioritizing barriers to organism establishment. ISME J 16, 331–338 (2022). https://doi.org/10.1038/s41396-021-01088-5
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Figure 1 – Noman, M.; Ahmed, T.; Ijaz, U.; Shahid, M.; Azizullah; Li, D.; Manzoor, I.; Song, F. Plant–Microbiome Crosstalk: Dawning from Composition and Assembly of Microbial Community to Improvement of Disease Resilience in Plants. Int. J. Mol. Sci. 2021, 22, 6852. https://doi.org/10.3390/ijms22136852