A powerful molecular engineering tool provided efficient Chlamydomonas mutants as bio-sensing elements for herbicides...

Area of Science:

• Biotechnology
• Environmental Science
• Molecular Biology

Background:

• Growing concerns exist regarding herbicide contamination in water and soil, posing ecological and human health risks.
• Whole-cell-based biosensors offer a promising tool for detecting these hazards but are limited by bio-recognition element stability and sensitivity.

Purpose of the Study:

• To engineer novel bio-sensing elements for improved herbicide detection.
• To overcome limitations in stability and sensitivity of whole-cell-based biosensors.

Main Methods:

• Utilized molecular engineering and in vitro directed evolution targeting the photosystem II (PSII) D1 protein in Chlamydomonas reinhardtii.
• Employed radical-generating ionizing radiation as a selection pressure to identify beneficial mutations.
• Conducted long-term stability tests and dose-response experiments for herbicide sensitivity.

Main Results:

• Identified D1 protein mutations conferring enhanced stability and tolerance to free-radical stress.
• Developed strains exhibiting increased sensitivity or resistance to triazine and urea herbicides, with I(50) values from 6 × 10(-8) M to 2 × 10(-6) M.
• Demonstrated the potential to improve biosensor specificity by combining herbicide-sensitive and resistant strains.

Conclusions:

• Molecular engineering of PSII D1 protein can significantly enhance whole-cell-based biosensor performance for herbicide detection.
• The developed mutants show improved stability and tailored sensitivity/resistance profiles for specific herbicides.
• This approach advances the development of robust and specific biosensors for environmental monitoring of herbicide contamination.