proteins. Cyanobacterial biofertilizers have been reported to be very useful in
ameliorating various physico-chemical properties of marginal soils, and the EPS
produced by the cyanobacteria seems to play an important role (Nisha et al. 2007).
The high sodium content in the soils leads to clogging of clay particles and reduce
the soil porosity in turn reflect on plant respiration and absorption of nutrients. The
extracellular polysaccharides excreted by cyanobacteria had been reported to be
responsible for binding of soil particles, thus leading to the formation of a tough and
entangled superficial structure that improves the stability of soil surface and protects
it from erosion. Certain cyanobacteria have been found not only to grow in saline
ecosystems but also to improve the physiochemical properties of the soil by
enriching them with carbon, nitrogen and available phosphorus. The potential
impact of these organisms on agriculture through their use as soil conditioners,
plant growth regulators and soil health ameliorators has been well-recognized. The
mechanism used by cyanobacteria to reclaim the saline soils are active export of ions
through K
+
/Na
+ channels and Na+/H+ antiporters, extracellular polymeric substance
(EPS) production, the accumulation of compatible solutes, defence enzyme productions, phytohormone production and nitrogen fixation (Li et al. 2019b).
Consortia of EPS-producing cyanobacteria results in the improvement of growth
in rice, maize and wheat under salt stress. It was found that the salt stress increases
the EPS production and showed significant removal of Na+ ions from solution thus
reduces the negative effect of salt concentration on crop plants (Arora et al. 2010).
Gene expression of salt stress related proteins were profiled in Synechocystis
sp. strain PCC 6803. It was found that genes responsible for PSI, PSII,
phycobilisomes, and synthesis of compatible solutes, such as ion homeostasis
were expressed well under salt-stressed condition and positively correlated with its
physiological process (Arora et al. 2010).
Desertification is another serious soil deterioration challenge for agriculture.
Desert soils are generally not suitable for cultivation due to less water activity and
abiotic stress factors. Inoculation of cyanobacteria in such lands could reverse the
state to crop cultivation. Through the formation of biological soil crust (BSC), it is
possible to restore the semi-arid and arid soils for agricultural practice. Biological
soil crust is a consortium of cyanobacteria, algae, fungi, bacteria, liches and mosses.
Such BSC plays an important role in stabilizing and predominantly colonizing desert
soil by increasing the quality of nutrients and moisture (Rossi et al. 2017). Though
the cyanobacteria forms BSC and retrieve the arid soils, it is a retard process. Hence
a novel technique was presented by Park et al. (2017), where cyanobacteria were
integrated with biopolymers and tackifiers such as polyvinyl alcohol (PVA) and
Tacki-Spray (TKS7) chemicals and added to the soils. As a result, it improves the
soil aggregation and pave the way for BSC formation. Beyond this, it promotes
cyanobacteria growth.
Cyanobacterial species were identified in different arid regions were reported
Chroococcidiopsis sp. from hyper arid zone, Chloroflexi sp. and Microcoleus
vaginatus from arid zone, Microcoleus vaginatus, Nostoc punctiforme and
Chroococcus sp. from semiarid zone and Chloroflexus sp. from dry sub-humid
zone (Perera et al. 2018). Apart from plant growth promotion, desert cyanobacteria
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K. G. Sabarinathan et al.
ameliorating various physico-chemical properties of marginal soils, and the EPS
produced by the cyanobacteria seems to play an important role (Nisha et al. 2007).
The high sodium content in the soils leads to clogging of clay particles and reduce
the soil porosity in turn reflect on plant respiration and absorption of nutrients. The
extracellular polysaccharides excreted by cyanobacteria had been reported to be
responsible for binding of soil particles, thus leading to the formation of a tough and
entangled superficial structure that improves the stability of soil surface and protects
it from erosion. Certain cyanobacteria have been found not only to grow in saline
ecosystems but also to improve the physiochemical properties of the soil by
enriching them with carbon, nitrogen and available phosphorus. The potential
impact of these organisms on agriculture through their use as soil conditioners,
plant growth regulators and soil health ameliorators has been well-recognized. The
mechanism used by cyanobacteria to reclaim the saline soils are active export of ions
through K
+
/Na
+ channels and Na+/H+ antiporters, extracellular polymeric substance
(EPS) production, the accumulation of compatible solutes, defence enzyme productions, phytohormone production and nitrogen fixation (Li et al. 2019b).
Consortia of EPS-producing cyanobacteria results in the improvement of growth
in rice, maize and wheat under salt stress. It was found that the salt stress increases
the EPS production and showed significant removal of Na+ ions from solution thus
reduces the negative effect of salt concentration on crop plants (Arora et al. 2010).
Gene expression of salt stress related proteins were profiled in Synechocystis
sp. strain PCC 6803. It was found that genes responsible for PSI, PSII,
phycobilisomes, and synthesis of compatible solutes, such as ion homeostasis
were expressed well under salt-stressed condition and positively correlated with its
physiological process (Arora et al. 2010).
Desertification is another serious soil deterioration challenge for agriculture.
Desert soils are generally not suitable for cultivation due to less water activity and
abiotic stress factors. Inoculation of cyanobacteria in such lands could reverse the
state to crop cultivation. Through the formation of biological soil crust (BSC), it is
possible to restore the semi-arid and arid soils for agricultural practice. Biological
soil crust is a consortium of cyanobacteria, algae, fungi, bacteria, liches and mosses.
Such BSC plays an important role in stabilizing and predominantly colonizing desert
soil by increasing the quality of nutrients and moisture (Rossi et al. 2017). Though
the cyanobacteria forms BSC and retrieve the arid soils, it is a retard process. Hence
a novel technique was presented by Park et al. (2017), where cyanobacteria were
integrated with biopolymers and tackifiers such as polyvinyl alcohol (PVA) and
Tacki-Spray (TKS7) chemicals and added to the soils. As a result, it improves the
soil aggregation and pave the way for BSC formation. Beyond this, it promotes
cyanobacteria growth.
Cyanobacterial species were identified in different arid regions were reported
Chroococcidiopsis sp. from hyper arid zone, Chloroflexi sp. and Microcoleus
vaginatus from arid zone, Microcoleus vaginatus, Nostoc punctiforme and
Chroococcus sp. from semiarid zone and Chloroflexus sp. from dry sub-humid
zone (Perera et al. 2018). Apart from plant growth promotion, desert cyanobacteria
148
K. G. Sabarinathan et al.