73
7.2 Future Microbiome Research Directions: How Do They
Engage Themselves?
As we explained earlier, microorganisms living in close proximity to crop plants
interact with them in many ways. Although the interaction is complex and has a
strong evolutionary linkage, such partnerships can have long-term impacts on both
crop plants and their respective microbial partners (Badri and Vivanco 2009; Tewari
and Arora 2013). The root systems act as a chemical repository for releasing specialized biomolecules to interact with numerous beneficial microorganisms such as
rhizobia, mycorrhizae, endophytes, and other plant growth-promoting microbes
(PGPMs) in the soil. As a result, a particular plant species could keep a highly specific microbial diversity in their rhizobiome, mainly through the modulation of
cross-talk between their roots and rhizospheric microbes through the mediation of
specific root exudates (Huang et al. 2014). Moreover, the exudation of a variety of
low molecular weight organic compounds (e.g., sugars, polysaccharides, amino
acids, organic acids, phenolic compounds), high molecular weight organic compounds (e.g., mucilage and proteins), and even volatile organic compounds (VOCs;
e.g., CO 2 , alcohols, aldehydes, terpenes) into the soil system would modify its physical, chemical, and biochemical properties by altering the nutrient stature, pH-redox
modulating factors, acidity, alkalinity, moisture content, porosity, permeability, particle density, and bulk density of the soil aggregates (Tewari and Arora 2013). Thus,
a plant species can customize its rhizobiome for the preferred microbial partners
(Berendsen et al. 2012). On the basis of the selectivity, specificity, and recognition
of various signaling cues, microorganisms can establish a precise association with a
host plant. In return, microorganisms produce various phytohormones such as auxins, cytokinins, gibberellins, abscisic acid, and polyamines for the growth and proliferation of the plant. Furthermore, most of the microbial volatiles have a key role
in eliciting induced systemic resistance (ISR) in plants. Apart from this, the PGPMs
reduce ethylene stress in plants by the secretion of ACC deaminase and are involved
in nutrient availability to plants by biological nitrogen fixation, phosphate, potassium, and zinc solubilization, and ion chelation by siderophore production (Ghosh
et al. 2014; Nadeem et al. 2014). Above all, microbial signals to plants improve the
cell metabolism, growth, development, and productivity. Because of the ecological
and health hazards of agrochemicals, soil and plant–microbiome research can be
adjudged as a sustainable solution for improving global agricultural productivity,
soil management, and ecosystem services that surely will meet the target of the
United Nations Sustainable Development Goals (SDGs). The aforesaid approaches
and convention explore the multifaceted applications of plant–microbe partnerships
for sustaining food production and plant, human, and environmental health. In such
a scenario, application of conventional methods, as well as the next-generation technologies (metagenomics, proteomics, transcriptomics), for studying the whole earth
microbiome and its associated ecosystem services is an urgent need. Recent global
statistics suggested that microbial diversity analyses across multiple research areas
are shifting to the use of next-generation sequencing (NGS) technologies (Fig. 7.1).
7.2 Future Microbiome Research Directions: How Do They Engage Themselves?
7.2 Future Microbiome Research Directions: How Do They
Engage Themselves?
As we explained earlier, microorganisms living in close proximity to crop plants
interact with them in many ways. Although the interaction is complex and has a
strong evolutionary linkage, such partnerships can have long-term impacts on both
crop plants and their respective microbial partners (Badri and Vivanco 2009; Tewari
and Arora 2013). The root systems act as a chemical repository for releasing specialized biomolecules to interact with numerous beneficial microorganisms such as
rhizobia, mycorrhizae, endophytes, and other plant growth-promoting microbes
(PGPMs) in the soil. As a result, a particular plant species could keep a highly specific microbial diversity in their rhizobiome, mainly through the modulation of
cross-talk between their roots and rhizospheric microbes through the mediation of
specific root exudates (Huang et al. 2014). Moreover, the exudation of a variety of
low molecular weight organic compounds (e.g., sugars, polysaccharides, amino
acids, organic acids, phenolic compounds), high molecular weight organic compounds (e.g., mucilage and proteins), and even volatile organic compounds (VOCs;
e.g., CO 2 , alcohols, aldehydes, terpenes) into the soil system would modify its physical, chemical, and biochemical properties by altering the nutrient stature, pH-redox
modulating factors, acidity, alkalinity, moisture content, porosity, permeability, particle density, and bulk density of the soil aggregates (Tewari and Arora 2013). Thus,
a plant species can customize its rhizobiome for the preferred microbial partners
(Berendsen et al. 2012). On the basis of the selectivity, specificity, and recognition
of various signaling cues, microorganisms can establish a precise association with a
host plant. In return, microorganisms produce various phytohormones such as auxins, cytokinins, gibberellins, abscisic acid, and polyamines for the growth and proliferation of the plant. Furthermore, most of the microbial volatiles have a key role
in eliciting induced systemic resistance (ISR) in plants. Apart from this, the PGPMs
reduce ethylene stress in plants by the secretion of ACC deaminase and are involved
in nutrient availability to plants by biological nitrogen fixation, phosphate, potassium, and zinc solubilization, and ion chelation by siderophore production (Ghosh
et al. 2014; Nadeem et al. 2014). Above all, microbial signals to plants improve the
cell metabolism, growth, development, and productivity. Because of the ecological
and health hazards of agrochemicals, soil and plant–microbiome research can be
adjudged as a sustainable solution for improving global agricultural productivity,
soil management, and ecosystem services that surely will meet the target of the
United Nations Sustainable Development Goals (SDGs). The aforesaid approaches
and convention explore the multifaceted applications of plant–microbe partnerships
for sustaining food production and plant, human, and environmental health. In such
a scenario, application of conventional methods, as well as the next-generation technologies (metagenomics, proteomics, transcriptomics), for studying the whole earth
microbiome and its associated ecosystem services is an urgent need. Recent global
statistics suggested that microbial diversity analyses across multiple research areas
are shifting to the use of next-generation sequencing (NGS) technologies (Fig. 7.1).
7.2 Future Microbiome Research Directions: How Do They Engage Themselves?