from the facultative CAM species Mesembryanthemum crystallinum or engineering
of CAM on-demand systems, for example, engineering of drought-responsive TFs in
various gene families like AP2/ERF, MYB, WRKY, NAC, NF-Y, bZIP from the
facultative and obligate CAM plant to the C3 species can enhance their drought
resistance with improved WUE. In the upcoming times, genetic circuits (e.g. toggle
switches, feedback loops, Boolean logic gates) linking CAM genes and droughtresponsive TFs through SynBio cycles will be necessary for drought avoidance and
tolerance (Yang et al. 2020). For improving salinity tolerance in plants, SynBio can
modify the expression of native genes of ion transport proteins (Shan et al. 2013;
Kumar and Jain 2015) and/or design novel artificial ion channels and transporters
with desired properties of ion selectivity filters and voltage sensors. Lot of research is
being carried out in this direction and de novo synthesis of functional Zn
2+ -
transporting four-helix transmembrane protein bundle by Joh et al. (2014) further
strengthens the feasibility of constructing artificial proteins with predefined transport
properties and for designing de novo regulatory networks [to design artificial plants
with desired salinity tolerance] (Volkov 2015). Moreover, salinity tolerance
pathways—including osmolyte synthesis, degradation of ROS, and altered signalling systems—are also being explored for engineering plants with the ability to grow
on saline soils (Roy et al. 2014). In another study by Ge et al. (2018), the combination of functional genes for cytosolic ABA receptor kinase 1 and regulatory
components of ABA receptor 11 with synthetic promoters (Ap, Dp and ANDp)
generated drought stress tolerance, as seen by application of exogenous ABA or
co-transformation with the effector dehydration-responsive element-binding
protein 2A.
15.6 Sustainable Bio-Manufacturing
Access to uncontaminated, inexpensive and trustworthy natural resources has been a
biology-driven keystone solution to the globally increasing affluence/carbon foot
printing since the establishment of the industrial revolution. Commercially
promising host organisms, i.e. prokaryotic blue-green algae (BGA) are appropriate
for the fabrication of tiny secretive molecules such as alcohols, organic acids and
fatty acids. In addition, eukaryotic microalgae can be engineered to produce storage
commodities such as proteins, lipids, starch and alkanes. Although, a number of
biofuels can be produced from BGA and eukaryotic microalgae (Wijffels et al.
2013), there are still many blockages that need to be resolved by SynBio tools
prior to their commercialisation. Currently, plant-based manufacturing,
i.e. Molecular Farming is being used for the production of commercially important
products such as enzymes, antibodies, biofuel, biopharmaceuticals, biocatalysts and
research-grade growth factors, cosmetic ingredients and many more. Members of
planta have come out as noteworthy fabrication platform for manufacturing recombinant proteins with the target to use them directly as the product in either plant itself
or in the form of purified or crude extract, rather than looking for a phenotypic or
metabolic transformation (Tschofen et al. 2016). In other words, superior production
15 Plant Synthetic Biology: A Paradigm Shift Targeting Stress Mitigation,. . .
459
of CAM on-demand systems, for example, engineering of drought-responsive TFs in
various gene families like AP2/ERF, MYB, WRKY, NAC, NF-Y, bZIP from the
facultative and obligate CAM plant to the C3 species can enhance their drought
resistance with improved WUE. In the upcoming times, genetic circuits (e.g. toggle
switches, feedback loops, Boolean logic gates) linking CAM genes and droughtresponsive TFs through SynBio cycles will be necessary for drought avoidance and
tolerance (Yang et al. 2020). For improving salinity tolerance in plants, SynBio can
modify the expression of native genes of ion transport proteins (Shan et al. 2013;
Kumar and Jain 2015) and/or design novel artificial ion channels and transporters
with desired properties of ion selectivity filters and voltage sensors. Lot of research is
being carried out in this direction and de novo synthesis of functional Zn
2+ -
transporting four-helix transmembrane protein bundle by Joh et al. (2014) further
strengthens the feasibility of constructing artificial proteins with predefined transport
properties and for designing de novo regulatory networks [to design artificial plants
with desired salinity tolerance] (Volkov 2015). Moreover, salinity tolerance
pathways—including osmolyte synthesis, degradation of ROS, and altered signalling systems—are also being explored for engineering plants with the ability to grow
on saline soils (Roy et al. 2014). In another study by Ge et al. (2018), the combination of functional genes for cytosolic ABA receptor kinase 1 and regulatory
components of ABA receptor 11 with synthetic promoters (Ap, Dp and ANDp)
generated drought stress tolerance, as seen by application of exogenous ABA or
co-transformation with the effector dehydration-responsive element-binding
protein 2A.
15.6 Sustainable Bio-Manufacturing
Access to uncontaminated, inexpensive and trustworthy natural resources has been a
biology-driven keystone solution to the globally increasing affluence/carbon foot
printing since the establishment of the industrial revolution. Commercially
promising host organisms, i.e. prokaryotic blue-green algae (BGA) are appropriate
for the fabrication of tiny secretive molecules such as alcohols, organic acids and
fatty acids. In addition, eukaryotic microalgae can be engineered to produce storage
commodities such as proteins, lipids, starch and alkanes. Although, a number of
biofuels can be produced from BGA and eukaryotic microalgae (Wijffels et al.
2013), there are still many blockages that need to be resolved by SynBio tools
prior to their commercialisation. Currently, plant-based manufacturing,
i.e. Molecular Farming is being used for the production of commercially important
products such as enzymes, antibodies, biofuel, biopharmaceuticals, biocatalysts and
research-grade growth factors, cosmetic ingredients and many more. Members of
planta have come out as noteworthy fabrication platform for manufacturing recombinant proteins with the target to use them directly as the product in either plant itself
or in the form of purified or crude extract, rather than looking for a phenotypic or
metabolic transformation (Tschofen et al. 2016). In other words, superior production
15 Plant Synthetic Biology: A Paradigm Shift Targeting Stress Mitigation,. . .
459