Salinity Stress Mitigation Using Encapsulated Biofertilizers for Sustainable Agriculture

Abstract

The harmful effect of salinity stress on crops needs to be mitigated. Therefore, the application of microbial inoculum in combination with nanomaterials and methyl salicylate was investigated. Initially, different seeds were exposed to salinity levels treated with variable microbial treatments using different modes of applications. The microbial treatments included application of cyanobacterial strain Cyanothece sp. and the rhizobacterium Enterobacter cloacae, alone or in combination with one another, and a final treatment using combined microbial inoculum supplied with methyl salicylate. Later, different nanomaterials were used, namely, graphene, graphene oxide, and carbon nanotubes in combination with biofertilizers on the highest salinity level. The nanomaterial with microbial treatment and methyl salicylate were applied partly as a mixture in soil and partly as capsules. Results showed that salinity stress had a drastic inhibitory effect on growth parameters, especially at −5 MPa level. Nonetheless, the microbial treatments significantly alleviated the deleterious effect of salinity stress, especially when combined with methyl salicylate. When the nanomaterials were added to biofertilizers at highest salinity level, the inhibitory effect of salinity was mostly alleviated. Smart use of synergistic biofertilizers alongside the right nanomaterial, both encapsulated and in soil, would allow for mitigation and alleviation of inhibitory effect of salinity.

Salinity Stress: Toward Sustainable Plant Strategies and Using Plant Growth-Promoting Rhizobacteria Encapsulation for Reducing It

“…Another study on soil salinity showed that cyanobacteria Cyanothece sp. and Rhizobacter enterobacter cloacae were encapsulated with methyl salicylate [119]. In addition, various nanomaterials such as graphene, graphene oxide, and carbon nanotubes were used in combination with biofertilizers against soil salinity in encapsulated form.…”

“…The bacteria tested included the cyanobacterial strain Cyanothece sp. and the rhizobacterium Enterobacter cloacae, which was applied to wheat in the field [119]. The results showed that this encapsulation reduced the destructive effect of salinity stress, especially when combined with methyl salicylate.…”

“…is a nitrogen-fixing and photosynthetic cyanobacterium that combines with a heterotrophic bacterium that actively inhales and consumes oxygen, thereby stabilizing nitrogen and producing CO 2 during respiration, thereby facilitating photosynthesis. These nanomaterials have a high level and can act as desalination agents and ion removers from soil salt solution when irrigated with saltwater, thus reducing the effects of salinity [119]. When released from the capsule or delivered in mulch, Rhizobacterium colonizes the root zone and makes it more efficient to absorb water and nutrients by absorbing growth hormone, which increases root growth [122].…”

Growth response, chlorophyll content, and nitrate reductase activity of mustard greens (Brassica rapa L.) to salinity stress post application of biofertilizer in hydroponic system

“…According to Semary et al (2020) different microbial treatment, mechanisms can reduce salinity stress. Recent studies have revealed that halotolerant rhizobacterials are able to reduce salinity stress by increasing root surface area through the regulation of phytohormones and gene expression when auxin increases and abscisic acid decreases.…”

Nitrogen-fixing Cyanothece sp. as a mixotroph and silver nanoparticle synthesizer: a multitasking exceptional cyanobacterium

“…is a nitrogen-fixing unicellular cyanobacterium that is capable of performing photosynthesis and nitrogen fixation in a diurnal cycle controlled by circadian rhythm. Many reports demonstrated its fantastic metabolic activities and physiological attributes including gold nanoparticle biosynthesis and plant biofertilization (Younis et al, 2019;El Semary et al, 2020). In order to exploit this cyanobacterium further and to grow it at minimal cost, we tested two natural different carbon sources including dextrose (glucose) derived from corn and soil extract as carbon sources.…”