environmental sensing, metabolic regulation and membrane transport were
expressed in R. leguminosarum. To analyse the specific processes in the rhizosphere,
study of reporter genes were successfully employed by many researchers to find out
the production of antimicrobial compounds, response of bacteria to nutrient availability (nitrogen, carbon, phosphorus), availability of water and temperature.
To evaluate the actual effect of root exudates on gene expression of microbes,
Mark et al. (2005) studied whole genome transcriptome profiling in P. aeruginosa
and found significant alterations happened due to the root exudates in sugar beet
cultivars. Metaproteogenomic approach was reported by Wang et al. (2011) to reveal
the complex interactions of plants and rhizospheric microbiome. MALDI-TOF
analysis reported 189 proteins in the rhizosphere of rice that actually originated
from plants, bacteria, fungi, and other faunas. Interestingly, by applying stable
isotope probing (SIP), scientists found that plant-derived carbon utilized into microbial nucleic acids could be tracked to explore the metabolically active population of
rhizobacteria. Exciting information was obtained when the plants like wheat, maize
and clover exposed to
13 CO
2À through DNA-SIP technology. Biomarker studies of
phospholipid fatty acids revealed that not only bacteria but also rhizospheric fungi
metabolized remarkable quantities of root exudates and confirmed through
13 CO 2 -
exposed plant study. So the provision of simply degradable root exudates in the
rhizosphere region also invites diversity of fungi to thrive in.
These fungi not only merely present in the rhizosphere, but it changes the
community dynamics by influencing and flourishing especially during flowering
and senescence of potato crop. Drigo et al. (2010) clearly indicated that through
DNA SIP studies that plant assimilated carbon is quickly transferred to AM fungi
that in turn slowly released to the rhizospheric bacterial and fungal communities and
pointed that combined approach in the rhizosphere is always found to be a powerful
tool to get the ultimate crop response.
Nowadays, the population growth and industrialization totally affected the global
ecosystems and 39% of terrestrial biomass (Ellis et al. 2010). Urbanization occupied
the cultivated land that lead scarcity of crop production, to produce more food in a
shorter period. Hence the farmers tend to use agrochemicals to produce high yields
in the small cultivated area. This will happen in developing countries too (Lichtfouse
et al. 2010). In the Green Revolution, the inorganic fertilizers and pesticides were
applied to produce foster food production in a shorter period of time (Shelton et al.
2012).
The liquid wastes from industries have heavy metal contamination that also
affects the soil fertility, water quality, plant growth and overall environmental
degradation and finally causes serious threat to human health (Oves et al. 2012).
In worldwide 22 million hectares of soil are highly affected by chemical pollution
especially in Europe and Asia (Bai et al. 2008). Pollution of ecosystem is the major
and emerging problem in the twenty-first century. A number of methods are available to meet food requirements without affecting environment, for this purpose
microbes play a vital role to ensure the food security during climatic change
(Timmusk et al. 2017).
6
M. Gomathy et al.
expressed in R. leguminosarum. To analyse the specific processes in the rhizosphere,
study of reporter genes were successfully employed by many researchers to find out
the production of antimicrobial compounds, response of bacteria to nutrient availability (nitrogen, carbon, phosphorus), availability of water and temperature.
To evaluate the actual effect of root exudates on gene expression of microbes,
Mark et al. (2005) studied whole genome transcriptome profiling in P. aeruginosa
and found significant alterations happened due to the root exudates in sugar beet
cultivars. Metaproteogenomic approach was reported by Wang et al. (2011) to reveal
the complex interactions of plants and rhizospheric microbiome. MALDI-TOF
analysis reported 189 proteins in the rhizosphere of rice that actually originated
from plants, bacteria, fungi, and other faunas. Interestingly, by applying stable
isotope probing (SIP), scientists found that plant-derived carbon utilized into microbial nucleic acids could be tracked to explore the metabolically active population of
rhizobacteria. Exciting information was obtained when the plants like wheat, maize
and clover exposed to
13 CO
2À through DNA-SIP technology. Biomarker studies of
phospholipid fatty acids revealed that not only bacteria but also rhizospheric fungi
metabolized remarkable quantities of root exudates and confirmed through
13 CO 2 -
exposed plant study. So the provision of simply degradable root exudates in the
rhizosphere region also invites diversity of fungi to thrive in.
These fungi not only merely present in the rhizosphere, but it changes the
community dynamics by influencing and flourishing especially during flowering
and senescence of potato crop. Drigo et al. (2010) clearly indicated that through
DNA SIP studies that plant assimilated carbon is quickly transferred to AM fungi
that in turn slowly released to the rhizospheric bacterial and fungal communities and
pointed that combined approach in the rhizosphere is always found to be a powerful
tool to get the ultimate crop response.
Nowadays, the population growth and industrialization totally affected the global
ecosystems and 39% of terrestrial biomass (Ellis et al. 2010). Urbanization occupied
the cultivated land that lead scarcity of crop production, to produce more food in a
shorter period. Hence the farmers tend to use agrochemicals to produce high yields
in the small cultivated area. This will happen in developing countries too (Lichtfouse
et al. 2010). In the Green Revolution, the inorganic fertilizers and pesticides were
applied to produce foster food production in a shorter period of time (Shelton et al.
2012).
The liquid wastes from industries have heavy metal contamination that also
affects the soil fertility, water quality, plant growth and overall environmental
degradation and finally causes serious threat to human health (Oves et al. 2012).
In worldwide 22 million hectares of soil are highly affected by chemical pollution
especially in Europe and Asia (Bai et al. 2008). Pollution of ecosystem is the major
and emerging problem in the twenty-first century. A number of methods are available to meet food requirements without affecting environment, for this purpose
microbes play a vital role to ensure the food security during climatic change
(Timmusk et al. 2017).
6
M. Gomathy et al.