Synthetic Biology in Plants, a Boon for Coming Decades

Synthetic biology for plant genetic engineering and molecular farming

Many efforts have been put into engineering plants to improve crop yields and stress tolerance and boost the bioproduction of valuable molecules. Yet, our capabilities are still limited due to the lack of well-characterized genetic building blocks and resources for precise manipulation and given the inherently challenging properties of plant tissues. Advancements in plant synthetic biology can overcome these bottlenecks and release the full potential of engineered plants. In this review, we first discuss the recently developed plant synthetic elements from single parts to advanced circuits, software, and hardware tools expediting the engineering cycle. Next, we survey the advancements in plant biotechnology enabled by these recent resources. We conclude the review with outstanding challenges and future directions of plant synthetic biology.

Solar-powered P450 catalysis: Engineering electron transfer pathways from photosynthesis to P450s

With the increasing focus on green chemistry, biocatalysis is becoming more widely used in the pharmaceutical and other chemical industries for sustainable production of high value and structurally complex chemicals. Cytochrome P450 monooxygenases (P450s) are attractive biocatalysts for industrial application due to their ability to transform a huge range of substrates in a stereo- and regiospecific manner. However, despite their appeal, the industrial application of P450s is limited by their dependence on costly reduced nicotinamide adenine dinucleotide phosphate (NADPH) and one or more auxiliary redox partner proteins. Coupling P450s to the photosynthetic machinery of a plant allows photosynthetically-generated electrons to be used to drive catalysis, overcoming this cofactor dependency. Thus, photosynthetic organisms could serve as photobioreactors with the capability to produce value-added chemicals using only light, water, CO2 and an appropriate chemical as substrate for the reaction/s of choice, yielding new opportunities for producing commodity and high-value chemicals in a carbon-negative and sustainable manner. This review will discuss recent progress in using photosynthesis for light-driven P450 biocatalysis and explore the potential for further development of such systems.

Genetic circuits in microbial biosensors for heavy metal detection in soil and water

With the rapid population growth, the world is witnessing an ever-increasing demand for energy and natural resources. Consequently, soil, air, and water are polluted with diverse pollutants, including heavy metals (HM). The detection of heavy metals is necessary to remediate them, which is achieved with biosensors. Initially, these HM were detected using atomic absorption spectroscopy (AAS), emission spectroscopy, mass spectrometry, gas chromatography etc., but these were costly and time consuming which further paved a way for microbe-based biosensors. The development of genetic circuits for microbe-based biosensors has become more popular in recent years for heavy metal detection. In this review, we have especially discussed the various types of genetic circuits such as toggle switches, logic gates, and amplification modules used in these biosensors as they are used to enhance sensitivity and specificity. Genetic circuits also allow for rapid and multiple analyte detection at the same time. The use of microbial biosensors for the detection of HM in the soil as well as the water is also described below. Although with a higher success rate than classical biosensors, these microbial biosensors still have some drawbacks like bioavailability and size of the analyte which are needed to be addressed.

Climate change challenges, plant science solutions

Climate change is a defining challenge of the 21st century, and this decade is a critical time for action to mitigate the worst effects on human populations and ecosystems. Plant science can play an important role in developing crops with enhanced resilience to harsh conditions (e.g. heat, drought, salt stress, flooding, disease outbreaks) and engineering efficient carbon-capturing and carbon-sequestering plants. Here, we present examples of research being conducted in these areas and discuss challenges and open questions as a call to action for the plant science community.