Chlorophyll to zeaxanthin energy transfer in nonphotochemical quenching: An exciton annihilation-free transient absorption study.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 39378097.
- Also identified by DOI 10.1073/pnas.2411620121 and PMC identifier 11494355.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Zeaxanthin (Zea) is a key component in the energy-dependent, rapidly reversible, nonphotochemical quenching process (qE) that regulates photosynthetic light harvesting. Previous transient absorption (TA) studies suggested that Zea can participate in direct quenching via chlorophyll (Chl) to Zea energy transfer. However, the contamination of intrinsic exciton-exciton annihilation (EEA) makes the assignment of TA signal ambiguous. In this study, we present EEA-free TA data using <i>Nicotiana benthamiana</i> thylakoid membranes, including the wild type and three NPQ mutants (<i>npq1</i>, <i>npq4</i>, and <i>lut2</i>) generated by CRISPR/Cas9 mutagenesis. The results show a strong correlation between excitation energy transfer from excited Chl Q<sub>y</sub> to Zea S<sub>1</sub> and the xanthophyll cycle during qE activation. Notably, a Lut S<sub>1</sub> signal is absent in the <i>npq1</i> thylakoids which lack zeaxanthin. Additionally, the fifth-order response analysis shows a reduction in the exciton diffusion length (L<sub>D</sub>) from 62 ± 6 nm to 43 ± 3 nm under high light illumination, consistent with the reduced range of exciton motion being a key aspect of plants' response to excess light.
Medical subject headings
- Zeaxanthins
- Chlorophyll
- Nicotiana
- Energy Transfer
- Thylakoids
- Photosynthesis