Synthetic biology (SynBio) encompasses approaches that design and construct new biological
elements (e.g. enzymes, genetic circuits, cells) or redesign existing biological systems to build new
and improved functions. SynBio ‘upgrades’ the potential of genetic engineering, which involves the
transfer of single genes from one organism to another. SynBio enables the introduction of multiple
genes in a single transgenic event, either from a donor organism or synthetically generated. It can
also enable the assembly of novel genomes from the ground up from a set of standardised genetic
parts, which can then be transferred into the target cell or organism. SynBio also offers a number of
non-breeding applications, such as topical applications in replacement of chemical pesticides, which
can be further utilised by stable transformation.
Conventional breeding techniques have successfully introduced several beneficial agronomic traits
into cotton, such as fibre quality attributes, crop maturity and disease resistance. The adoption of
modern biotechnology approaches has enabled developments beyond the capacity or efficiency of
conventional breeding, such as broad-scale insect and herbicide resistance. However, cotton yields
continue to be challenged by abiotic and biotic factors. In addition, while progress in traditional
breeding is yet to reach a ceiling, genetic diversity in cultivated cotton germplasm is limited (Wendel
et al., 1992, Iqbal et al., 2001). Therefore, more advanced cotton cultivar development approaches
are required to maintain and improve cotton yields and production efficiency, especially as climate
change increases the incidence of biotic and abiotic challenges.
This report describes several applications of synthetic biology to the cotton industry. The most
promising synthetic biology tools and approaches are discussed. Five major areas of potential
application of SynBio are discussed, with the following conclusions:
Insect pests: Potential long-term investment in developing RNAi trait against silverleaf whitefly.
Fungal diseases: Currently constrained by significant fundamental knowledge gaps.
Carbon assimilation: Research currently supported by CRDC in preparation for SynBio application in
the next 3 - 6 years. Additional opportunities (i.e. aquaporins) exist, warranting further research.
Nutrient acquisition: Long and short-term (scoping) investment opportunities in fundamental
research towards microbe attracting/enhancing root exudates via CRISPR-Cas9 or Golden Gate.
Seed oil quality: Currently an unviable investment opportunity in Australia.
Importantly, the challenges facing SynBio application in cotton include the need for more in-depth
fundamental genetic information and the need for a transformation system that is available for elite
cotton germplasm.